UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No.    )

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Horizon Pharma Public Limited Company

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HORIZON PHARMA PUBLIC LIMITED COMPANY

ANNUAL GENERAL MEETING OF SHAREHOLDERS

May 3, 20172018

NOTICE AND PROXY STATEMENT

                    , 2017April 2, 2018

Dear Fellow Shareholder:

In 2016, Horizon Pharma delivered another exceptional2017 was a year of financial performancesignificant progress for Horizon Pharma.  Having rapidly transformed the Company into one focused primarily on rare and rheumatic diseases over the past five years, we launched the next stage of our shareholders.evolution – developing a robust pipeline of clinically meaningful medicines to drive sustained growth over the long term.  We added several new programs to our pipeline in 2017, includingHZN-001 (teprotumumab), a late-stage fully human monoclonal antibody (mAb) insulin-like growthfactor-1 receptor(IGF-1R) inhibitor, which is a candidate for the treatment ofmoderate-to-severe thyroid eye disease, a rare eye disease.  Enrollment in the confirmatory Phase 3 clinical trial began in the fourth quarter of 2017 and we project that, if approved, teprotumumab could achieve peak annual U.S. net sales of more than $750 million.  We also achieved an important milestone foradded two otherpre-clinical rheumatology programs designed to enhance our company, surpassing $980 millionleadership in GAAPthe treatment of uncontrolled gout¹, a position which we hold today with our rare-disease biologic KRYSTEXXA^®, one of our key growth drivers.  We continued to invest in KRYSTEXXA in 2017 by doubling its commercial organization and expanding its targeted patient population to include uncontrolled gout patients treated by nephrologists.  As a result, we recently increased our estimate of KRYSTEXXA peak annual net sales and $1 billion innon-GAAP adjusted net sales¹ following rapid growth and transformationto more than $750 million. 

These developments exemplify the successful execution of our strategy over the lastpast five years.  In 2011, for perspective, we generated $7 million in sales in our first year as a publicly traded company.

We’ve accomplished a great deal over the last five years – executing on our organic growth opportunities, evolving our business model and completing six acquisitions that have diversified our company from2013, Horizon Pharma had two to 11 medicines led now by our fast-growing orphan medicines.

In 2016, we delivered GAAP net sales andnon-GAAP adjustedwith net sales of $981$74 million.  Today, we are a biopharmaceutical company focused primarily on rare diseases, with 11 medicines, six of them for rare diseases, and our rare disease medicines making up approximately 60 percent of our 2017 net sales.  This rapid, transformational growth has resulted in a five-year total shareholder return of 527 percent, significantly outperforming our peer group² and the Nasdaq Biotechnology Index (NBI). 

Our net sales of $1.06 billion in 2017 represented a year-over-year increase of 8 percent on a GAAP basis and 1 percent on anon-GAAP basis³, driven primarily by strong growth in our orphan and rheumatology business units.  Impacting our net sales performance were challenges we experienced early in the year in our primary care business unit related to the implementation of a new contracting model with pharmacy benefit managers (PBMs), which we effected primarily in response to the increasing level of control in the managed care environment.  Despite the resulting negative impact of approximately $230 million and $1.046 billion¹, respectively, increases of 30 percent and 38 percent, respectively,to our primary care business unit net sales, our diversification strategy over the prior year, driven bypast three years proved successful, as the growth in eachnet sales of our three business units: orphan, rheumatology and primary care. In 2016, our GAAPrare disease medicines of 60 percent more than offset that decrease, resulting in year-over-year net sales growth.  Our 2017 net loss,non-GAAP adjusted net income and adjusted EBITDA²⁴ were $167$411 million,³, $354 $195 million and $471$390 million respectively⁴⁵., respectively.  We also ended 20162017 with a cash balance of $509 million.

In addition$751 million, providing us with the financial flexibility to delivering oncontinue to execute our financial commitments, we continued to shape and transform our company, completing two strategic transactions that brought us three rare disease medicines – KRYSTEXXA, for refractory chronic gout, PROCYSBI for the rare genetic disease, nephropathic cystinosis, and QUINSAIR for chronic pulmonary infections associated with cystic fibrosis. We expect KRYSTEXXA and PROCYSBI in particular to be meaningful growth drivers for our orphan business and we believe that combined both medicines will exceed $550 million in peak year sales. We also secured contracts with three leading pharmacy benefit managers to improve patient access and long-term durability for our clinically differentiated primary care medicines.

While our talented team of employees executed well on our business strategy over the past year, 2016 was a challenging year for our sector and our share price, driven in part by uncertainty surrounding U.S. healthcare policy, which has continued into 2017. Horizon Pharma’s one-year total shareholder return in 2016 declined 25 percent, in line with our peer group⁵ as well as the NASDAQ Biotechnology Index (NBI). However, a longer-term view on our total shareholder return demonstrates that Horizon Pharma has significantly outperformed its peer group and the NBI over the last three- and five-year periods: up 112 percent in the three-year period, as compared to 19 percent for our peer group and 18 percent for the NBI and up nearly 305 percent in the five-year period, as compared to 210 percent for our peer group and 159 percent for the NBI.

We were also recognized in multiple “Best Places to Work Surveys” in 2016, including the 2016Crain’s Chicago Business Best Places to Work for Women Over 35, 2016 100 Best Medium Workplaces byFortune Magazine and 2016Chicago Tribune’s Top Midsize Workplaces.strategy. 

Overall, I am very pleased with our team’s performance.  We remained diligently focused on strong execution and driving the business forward.  We demonstrated the commitment that underscores everything we do at Horizon Pharma:  making a powerful difference for the patients, caregivers and physicians through the innovative medicines we commercialize and develop to address unmet treatment needs.  The dedication and purpose of our talented team of employees is reflected in the recognition Horizon Pharma continues to receive, including threeFortune Magazine 2017 surveys – One of the Best Workplaces in Health Care, 100 Best Small & Medium Workplaces and 2017 Best Work Places to Work in Chicago – as well as the 2017Crain’s Chicago Business Best Places to Work andChicago Tribune’s 2017 TopMedium-Sized Workplaces.  Our ongoing efforts to diversify our employee base has helped us achieve our goals.  To drive our continued growth and evolution in this regard, Irina Konstantinovsky, an accomplished human resources professional, joined us in September 2017 as executive vice president, chief human resources officer.

More recently, we were very pleased to welcomeShao-Lee Lin, M.D., Ph.D., who joined Horizon Pharma earlier this year as executive vice president, head of research and development (R&D) and chief scientific officer. Shao-Lee brings exceptional experience and a proven track record of developing new medicines – and she shares our focus on improving patient outcomes. Shao-Lee is focused on driving the accelerated development of a R&D portfolio of medicines for Horizon Pharma, leading the next phase of growth for the Company. 

We are delivering on our core principles including– strong commercial execution, a disciplined business development strategy, the clinical development of medicines for patients in need and expanding patient access – while also increasing affordability of our medicines.  Moving forward, we will continue to drive and motivate our growing organization with the goal of delivering continued strong financial performance that creates long-term market-leading shareholder value.

You are cordially invited to attend the Annual General Meeting of Shareholders on Wednesday,Thursday, May 3, 2017,2018, at 3:00 p.m. local time at our corporate headquarters located at Connaught House, 1^st1st Floor, 1 Burlington Road, Dublin 4, D04 C5Y6, Ireland.

Whether or not you plan to attend the Annual General Meeting, it is important that your shares be represented and voted.  Please take a moment now to vote your shares by internet, by toll-free telephone call or by signing, dating and datingreturning the enclosed proxy card.

Thank you for your continued support.

Important Notice Regarding the Availability of Proxy Materials for the Annual General Meeting of

Shareholders to Be Held on Wednesday,Thursday, May 3, 2017,2018, at 3:00 p.m. Local Time at Our Corporate

Headquarters Located at Connaught House, 1st Floor, 1 Burlington Road, Dublin 4, D04 C5Y6, Ireland.

Dear Shareholder:

We will be holding the Annual General Meeting of Shareholders of Horizon Pharma plc on Wednesday,Thursday, May 3, 2017,2018, at 3:00 p.m. local time at our corporate headquarters located at Connaught House, 1st Floor, 1 Burlington Road, Dublin 4, D04 C5Y6, Ireland for the following purposes:

The Board recommends that you vote FOR each of the nominees for director named herein, for ONE YEAR as the preferred frequency of advisory votes to approve executive compensation and FOR Proposals 2, through 5.3, 5 and 6. 

Our Irish statutory financial statements for the fiscal year ended December 31, 2016,2017, including the reports of the directors and statutory auditors thereon, will be presented at the Annual General Meeting.  There is no requirement under Irish law that such statements be approved by the shareholders and no such approval will be sought at the Annual General Meeting.

For the purposes of our Articles of Association, Proposals 1 and 2 and the receipt and consideration of the Irish statutory financial statements by us at the Annual General Meeting are deemed to be ordinary business and Proposals 3, 4, 5 and 56 are deemed to be special business.  Shareholders of record as of March 6, 2017,23, 2018, the record date for the Annual General Meeting, are entitled to notice of the Annual General Meeting and to vote at the Annual General Meeting or any adjournment or postponement thereof.

We ask that you review the Proxy Statement carefully and complete, sign, date and return the enclosed proxy card in the envelope provided or vote over the internet or by telephone as instructed in these materials, as promptly as possible in order to ensure your representation at the meeting.  A return envelope (which is postage prepaid if mailed in the United States) has been provided for your convenience.  Even if you have voted by proxy, you may still vote in person if you attend the meeting.  Please note, however, that if your shares are held of record by a broker, bank or other nominee and you wish to vote at the meeting, you must obtain a proxy issued in your name from that record holder.

The Proxy Statement and Annual Report to shareholders are available atwww.edocumentview.com/hznp.

By Order of the Board of Directors

David G. Kelly

Company Secretary

Dublin 4, Ireland

                    , 2017April 2, 2018

PROXY STATEMENT SUMMARY

This summary highlights certain information contained elsewhere in this Proxy Statement and does not contain all of the information that you should consider.  You should read the entire Proxy Statement carefully before voting.  For more complete information regarding our business and 20162017 performance, please review our Annual Report on Form10-K for the year ended December 31, 2016.2017. 

Voting Items and Board Recommendations

Business Overview

In 2016, we delivered strong results to create long-term value for our shareholders. We continued tomade significant progress in 2017 on our long-term strategy of building a more-diversifieddiversified and durable, high-growth biopharmaceutical company anchored by a growing mix offocused on rare disease medicines.  We have grown both organically and through strategic acquisitions and today have 11generated full-year net sales of $1.06 billion, with our rare disease medicines, across three business units: orphan, rheumatology and primary care.

Meeting and Voting Information

Strong and Consistent Financial Performance

now representing approximately 60 percent of our net sales, increasing 60 percent year-over-year.  In 2016, we delivered another record sales year and achieved an important milestoneaddition to expanding the commercial efforts for our company, surpassing $1 billion innon-GAAP adjustedkey growth driver KRYSTEXXA, which we now believe has peak net sales potential of more than $750 million, we augmented our pipeline with the addition ofHZN-001 (teprotumumab), a late-stage development fully human monoclonal antibody (mAb) insulin-like growthfactor-1 receptor(IGF-1R) inhibitor candidate for the treatment ofmoderate–to-severe thyroid eye disease (TED), as well as several new rheumatology pipeline programs. 

Our Strategy

Our strategy has evolved over three phases.  When we first launched as a public company in 2016 following2011, we rapidly established Horizon Pharma’s infrastructure and commercial footprint, generating earnings and cash flow through the commercialization of our first two medicines, DUEXIS and RAYOS.  In 2014, we began the second phase of our strategy, which focused on rapid growthdiversification into rare disease medicines through key acquisitions that brought us ACTIMMUNE, RAVICTI, KRYSTEXXA and transformationPROCYSBI.  In 2017, we began the third phase of our strategy, building out a pipeline of differentiated and clinically meaningful, development-stage medicines to drive sustainable growth over the last five years. In 2011, for perspective,long term.  At the same time, we generated $7 million in sales inremain focused on commercial execution and optimizing the growth of our first yearrare disease medicines, as a publicly traded company.well as considering future commercial asset acquisitions. 

Diversification andRare Disease Medicines Are Driving Our Sales Growth

We’ve accomplished a great deal over the last five years – executing onNet sales of our organic growth opportunities, evolving our business model and completing six acquisitions that have diversified our company from two medicines in 2013 to 11 medicines in 2016 across three business units: orphan, rheumatology and primary care.

In addition to delivering on our financial commitments, we continued to shape and transform our company in 2016, completing two strategic transactions that brought us three rare disease medicines –grew 60 percent in 2017 compared to 2016.  Net sales of KRYSTEXXA for refractory chronic gout, PROCYSBIalone, our medicine for the treatment of uncontrolled gout, a rare genetic disease, nephropathic cystinosis,grew 72 percent in 2017, following the implementation of our commercial strategy to maximize the medicine’s growth trajectory following its acquisition in January of 2016.  We believe KRYSTEXXA has significant future growth potential and QUINSAIRinvested substantially in its commercial organization in 2017, doubling its size to not only increase penetration in the rheumatology market, but also to expand into nephrology, a new market for chronic pulmonary infections associatedKRYSTEXXA.  We estimate that the nephrology market has a similar addressable patient population as rheumatology, approximately 50,000 patients.  Our orphan business unit, which includes RAVICTI, PROCYSBI and ACTIMMUNE, provides us with cystic fibrosis. a stable base of rare disease growth medicines. 

CAGR:  compound annual growth rate

Expanding Our Pipeline to Drive Sustainable Long-Term Growth

In May 2017, we acquired River Vision Development Corp.  (River Vision), which added the first development-stage candidate to our pipeline – teprotumumab, a fully human monoclonal antibody (mAb) inhibitor ofIGF-1R. Teprotumumab, also known asHZN-001, demonstrated breakthrough efficacy in its Phase 2 trial in patients withmoderate-to-severe TED, a rare and debilitating eye disease with no approved therapies.  Enrollment in the Phase 3 confirmatory trial began in October 2017 and we expect to complete enrollment by the end of 2018.  We estimate the addressable population in the United States to be between 15,000 and 20,000 patients annually. 

We also delivered onexpanded our commitmentrheumatology pipeline programs in 2017, adding two next-generation biologic development programs to secure greater formulary accesssupport and sustain our leadership in the treatment of uncontrolled gout, as well asHZN-002, a novel dexamethasone conjugate, to augment our rheumatology portfolio.  In addition, two investigator-initiated immunomodulation studies are expected to start in 2018 to evaluate enhancing the response rate for our primary care medicines providing improved patient accessKRYSTEXXA. 

TRIPLE: TolerizationReducesIntolerance toPegloticase and long-term durability for our clinically differentiated primary care medicines.Prolongs the UrateLoweringEffect.  RECIPE: REduCingImmunogenicity toPegloticasE.  RIFLE: RAYOS (delayed release prednisone)InhibitsFatigue inLupusErythematosus.  OPTIC:  Treatment of Graves’Orbitopathy (Thyroid Eye Disease) to ReduceProptosis withTeprotumumabInfusions in a Randomized, Placebo-Controlled, Clinical Study.  CTCL:  cutaneousT-cell lymphoma.  HER2:  human epidermal growth factor receptor 2. 

Total Shareholder Return

While our talented team of employees executed well on our business strategy overOver the past year, 2016 was a challenging year for our sectorthree- and our share price, driven in part by uncertainty surrounding U.S. healthcare policy, which has continued into 2017. Our one-year TSR in 2016 declined 25 percent, in line with our peer group as well as the NBI. However, a longer-term view on our TSR demonstrates thatfive-year periods, we have significantly outperformed both our peer group and the NBI overNasdaq Biotechnology Index (NBI).  With our durable base of rare disease medicines, our high-growth KRYSTEXXA medicine and the last three-and five-year periods.pipeline we are building for future growth, we believe Horizon Pharma is well positioned for rapid and sustainable long-term growth. 

Note:  The peer group used for the TSR calculations for the1-, 3-,3- and5-year periods endingended December 31, 20162017 is our August 2015May 2017 peer group (shown on page 28) but excludes Medivation, Inc. from such calculations because it was acquired by Pfizer, Inc. in September 2016.33). 

Director Nominees and Continuing Directors

Our Board, which is not standing forre-electionpredominantly independent, includes a range of newer and longer-tenured directors.  In addition, the Board values diversity, with an expansive definition of diversity that includes differences of experience, education, talents, gender and race.  The addition of Pascale Witz to the Board in May 2017.

Corporate Governance Highlights

Executive Compensation Overview

Our executive compensation program emphasizes three major pay considerations, and this is how we currently achieve them.them:

With a strategic focus on growing the business over the long term, it is imperative that our executive compensation program motivates our talented management team in such a manner as to encourage – and reward – successful execution of this business strategy.  We utilize the following compensation elements to achieve this:

Shareholder Engagement

We value the views of our shareholders and we have madehad significant and meaningful engagement with our shareholders onregarding our compensation and governance issues a priority.governance.  Feedback garnered during these outreach efforts informs the Compensation Committee’s thinking when evaluating our current compensation program and when considering potential modifications to the program on ago-forward basis.  For the past threefour years, led by the Chairman of our Compensation Committee, we have conducted continued and consistent engagement with our shareholders.shareholders and we plan to continue this practice. 

Last year at the 2016At our 2017 Annual General Meeting of Shareholders,oursay-on-pay proposal proposal received the support of approximately 6497 percent of the shares voted.  Our Board was disappointed inWe believe this outcome and, through shareholder engagement, we realized that several shareholders were not supportivehigh level of the front-loaded equity grant approach (where we granted three-year performance shares tosupport is a result of our executive team) in 2015 and the reported value of those grants (although the realized value was and still is effectively zero).

Since that meeting, our Compensation Committee and management has conducted a comprehensive shareholder outreach and engagement program to solicit feedback, understand investor concernsviewpoints and incorporate feedback into further discuss the mechanisms and rationale of the 2015 grants. We reached out to shareholders representing more than 40 percentdiscussions of our outstanding ordinary shares, as well as two of the leading proxy advisory firms, Institutional Shareholder Services, Inc.compensation programs and Glass Lewis & Co. These discussionsphilosophy. 

Through this shareholder engagement we have beenhad very productive conversations, which continue to shape our programs and informative, and have helped ensuredisclosures.  Recent changes that our Board’s ongoing decisions are aligned withwere heavily influenced by shareholder objectives. During these discussions, our shareholders have generally been supportive of our business and growth strategy as well as our compensation philosophy.

In addition, in response to the input we received from our shareholders during these discussions:feedback include:

Additionally, as we have previously committed, at the expiration of the three-year PSU performance period in 2018, any of the PSUs that are not earned due to our failure to attain the requisite performance criteria will be cancelled at such time and the related ordinary shares will not be added back in the pool of shares available for grant under our equity plan.

Please see our Compensation Discussion and Analysis on page 2025 for additional information on our compensation philosophy.

QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING

Why am I receiving these materials?

We have sent you these proxy materials because our Board is soliciting your proxy to vote at the Annual General Meeting, including at any adjournments or postponements of the meeting.  You are invited to attend the Annual General Meeting to vote on the proposals described in this Proxy Statement.  However, you do not need to attend the meeting to vote your shares.  Instead, you may simply complete, sign and return the enclosed proxy card, or follow the instructions below to submit your proxy over the telephone or through the internet.

How do I attend the Annual General Meeting?

The meeting will be held on Wednesday,Thursday, May 3, 2017,2018, at 3:00 p.m. local time at our corporate headquarters located at Connaught House, 1^st Floor, 1 Burlington Road, Dublin 4, D04 C5Y6, Ireland.  Directions to the Annual General Meeting may be found athttps://www.google.com/maps/place/Connaught+House,+Burlington+Rd,+Dublin+4,+Ireland.  Information on how to vote in person at the Annual General Meeting is provided below.  However, you do not need to attend the Annual General Meeting to vote your ordinary shares.

Who can vote at the Annual General Meeting?

Only shareholders of record at the close of business on March 6, 201723, 2018 will be entitled to vote at the Annual General Meeting.  On this record date, there were 162,362,764164,975,527 of our ordinary shares outstanding and entitled to vote.

Shareholder of Record (shares registered in your name).If on March 6, 2017,23, 2018, your shares were registered in your name in our Register of Members which is maintained by Horizon Pharma’sour transfer agent, Computershare Shareowner Services LLC, then you are a shareholder of record.  As a shareholder of record, you may vote in person at the meeting or vote by proxy.  Whether or not you plan to attend the meeting, we urge you to fill out and return the enclosed proxy card or vote by proxy over the telephone or on the internet as instructed below to ensure your vote is counted.

Beneficial Owner (shares registered in the name of a broker or bank).If on March 6, 2017,23, 2018, your shares were not registered in your name in our Register of Members, but rather held in an account at a brokerage firm, bank, dealer or other similar organization, then you are the beneficial owner of shares held in “street name” and these proxy materials are being forwarded to you by that organization.  The organization holding your account is considered to be the shareholder of record for purposes of voting at the Annual General Meeting.  As a beneficial owner, you have the right to direct your broker or other agent regarding how to vote the shares in your account.  You are also invited to attend the Annual General Meeting.  However, since you are not the shareholder of record, you may not vote your shares in person at the meeting unless you request and obtain a valid proxy from your broker or other agent.

What am I voting on?

There are fivesix matters scheduled for a vote:

What if another matter is properly brought before the meeting?

The Board knows of no other matters that will be presented for consideration at the Annual General Meeting.  If any other matters are properly brought before the meeting, it is the intention of the persons named in the accompanying proxy to vote on those matters in accordance with their best judgment.

How do I vote?

You may vote “For” or “Against” each Class IIII director nominee or you may abstain from voting for all or any of the nominees.  With regard to the advisory vote on how frequently we should solicit shareholder advisory approval for executive compensation, you may vote for any one of the following:  one year, two years or three years or you may abstain from voting on that matter.  For each of the other matters to be voted on, you may vote “For” or “Against” or abstain from voting.

The procedures for voting are fairly simple:

Shareholder of Record.If you are a shareholder of record, you may vote in person at the Annual General Meeting, vote by proxy using the enclosed proxy card, vote by proxy over the telephone or vote by proxy through the internet.  Whether or not you plan to attend the meeting, we urge you to vote by proxy to ensure your vote is counted.  You may still attend the meeting and vote in person even if you have already voted by proxy.

Beneficial Owner.If you are a beneficial owner of shares registered in the name of your broker, bank or other agent, you should have received a voting instruction form with these proxy materials from that organization rather than from us.  Simply complete and mail the voting instruction form to ensure that your vote is counted.  Alternatively, you may vote by telephone or through the internet as instructed by your broker or bank.  To vote in person at the Annual General Meeting, you must obtain a valid proxy from your broker, bank or other agent.  Follow the instructions from your broker or bank included with these proxy materials, or contact your broker or bank to request a proxy form.

Joint Holders.In the case of joint holders of record, any one of such holders may vote either in person or by proxy in respect thereof as if he or she were the sole holder thereof, but the vote of the senior holder who tenders a vote, whether in person or by proxy, shall be accepted to the exclusion of the votes of the other joint holders, and for this purpose seniority shall be determined by the order in which the names stand in the Company’sour Register of Members.

How many votes do I have?

On each matter to be voted upon, you have one vote for each ordinary share you own as of March 6, 2017.23, 2018. 

What happens if I do not vote?

Shareholder of Record.If you are a shareholder of record and do not vote by completing your proxy card, by telephone, through the internet or in person at the Annual General Meeting, your shares will not be voted.

Beneficial Owner.If you are a beneficial owner and do not instruct your broker, bank, or other agent how to vote your shares, the question of whether your broker or nominee will still be able to vote your shares depends on whether the New York Stock Exchange (NYSE) deems the particular proposal to be a “routine” matter.  Brokers and nominees can use their discretion to vote “uninstructed” shares with respect to matters that are considered to be “routine,” but not with respect to“non-routine” matters.  Under the rules and interpretations of the NYSE,“non-routine” matters are matters that may substantially affect the rights or privileges of shareholders, such as mergers, shareholder proposals, elections of directors (even if not contested), executive compensation (including any advisory shareholder votes on executive compensation) and certain corporate governance proposals, even if management-supported.  Accordingly,We have been advised by the NYSE that your broker or nominee may not vote your shares on Proposals 1, 3, 4 or 56 without your instructions, but may vote your shares on Proposal 2.Proposals 2 and 5. 

What if I return a proxy card or otherwise vote but do not make specific choices?

If you return a signed and dated proxy card or otherwise vote without marking voting selections, then the Companyour designated proxy holders (one of the individuals named on your proxy card) will vote your shares in the manner recommended by our Board on all matters presented in this Proxy Statement and as the proxy holders may determine in their discretion regarding any other matters properly presented for a vote at the meeting.  If any other matter is properly presented at the meeting, your proxy holder will vote your shares using his or her best judgment.

Who is paying for this proxy solicitation?

We have retained MacKenzie Partners, Inc. (MacKenzie), a proxy solicitation firm, to solicit proxies in connection with the Annual General Meeting at a cost of approximately $20,000 plus expenses.  The cost of soliciting proxies incurred by the Companyus and MacKenzie, including the preparation, assembly and mailing of the proxies and soliciting material, as well as the cost of forwarding such material to beneficial owners of the Company’sour ordinary shares, will be borne by the Company. Directors,us.  Our directors, officers and regularother employees of the Company may, without compensation other than their regular remuneration, solicit proxies personally or by telephone.

What does it mean if I receive more than one set of proxy materials?

If you receive more than one set of proxy materials, your shares may be registered in more than one name or in different accounts.  Please follow the voting instructions on the proxy cards in each set of proxy materials to ensure that all of your shares are voted.

Can I change my vote after submitting my proxy?

Shareholder of Record.Yes, you canmay revoke your proxy at any time before the final vote at the meeting.  If you are the record holder of your shares, you may revoke your proxy in any one of the following ways:

Your most current proxy card or telephone or internet proxy is the one that is counted.

Beneficial Owner.  If your shares are held by your broker or bank as a nominee or agent, you should follow the instructions provided by your broker or bank.

Do I need a ticket to attend the Annual General Meeting?

You will need an admission ticket or proof of ownership of ordinary shares to enter the Annual General Meeting.  If you are a shareholder of record, your admission ticket is the top half of the proxy card sent to you.  If you plan to attend the Annual General Meeting, please so indicate when you vote and bring the ticket with you to the Annual General Meeting.  If your shares are held in the name of a bank, broker or other holder of record, you do not need an admission ticket, but you will need proof of ownership to be admitted to the Annual General Meeting.  A recent brokerage statement or letter from a bank or broker is an example of proof of ownership.  If you arrive at the Annual General Meeting without an admission ticket or proof of ownership of ordinary shares, we will admit you only if we are able to verify that you are a shareholderone of our company.shareholders. 

How are votes counted?

Votes will be counted by the inspector of election appointed for the meeting, who will separately count, with respect to the proposal to elect directors, votes “For,” “Against,” abstentions and brokernon-votes; with respect to the proposal regarding frequency of shareholder advisory votes to approve executive compensation, votes for eachfrequencies of theone year, two years or three years, abstentions and brokernon-votes; and, with respect to other proposals, votes “For” and “Against,” abstentions and, as applicable, brokernon-votes.Abstentions and brokernon-votes will be treated as shares present for the purpose of determining the presence of a quorum for the transaction of business at the Annual General Meeting.  Abstentions and brokernon-votes will not, however, be considered votes cast at the Annual General Meeting.  Because the approval of all of the proposals is based on the votes cast at the Annual General Meeting, abstentions and brokernon-votes will not have any effect on the outcome of voting on the proposals.

What are “brokernon-votes”?

As discussed above, when a beneficial owner of shares held in “street name” does not give instructions to the broker or nominee holding the shares as to how to vote on matters deemed by the NYSE to be“non-routine,” the broker or nominee cannot vote the shares.  Theseun-voted shares are counted as “brokernon-votes.”

What is the quorum requirement?

A quorum of shareholders is necessary to hold a valid meeting.  A quorum will be present if shareholders holding a majority of the issued and outstanding ordinary shares entitled to vote are present at the meeting in person or represented by proxy.  On the record date, there were 162,362,764164,975,527 ordinary shares outstanding and entitled to vote.  Thus, the holders of 81,181,38382,487,764 ordinary shares must be present in person or represented by proxy at the meeting to have a quorum.

Your shares will be counted towards the quorum only if you submit a valid proxy (or one is submitted on your behalf by your broker, bank or other nominee) or, provided that you are a shareholder of record, if you vote in person at the meeting.  Abstentions and brokernon-votes will be counted towards the quorum requirement.  If there is no quorum, within one hour of the time appointed for the Annual General Meeting, the Annual General Meeting will stand adjourned to May 10, 2017,2018, at 3:00 p.m. local time at the same location, or such other time or place as the Board may determine.

Assuming there is a quorum of shares present at the Annual General Meeting, how many votes are needed to approve each proposal?

How can I find out the results of the voting at the Annual General Meeting?

Preliminary voting results will be announced at the Annual General Meeting.  In addition, final voting results will be published in a current report on Form8-K that we expect to file within four business days after the Annual General Meeting.  If final voting results are not available to us in time to file a Form8-K within four business days after the meeting, we intend to file a Form8-K to publish preliminary results and, within four business days after the final results are known to us, file an additional Form8-K to publish the final results.

What are the Irish statutory financial statements?

We are presenting our Irish statutory financial statements, including the reports of the directors and the statutory auditors thereon, at the Annual General Meeting, and we are making a copy of them available for download in PDF format in the Investors section (see Annual Reports subsection) of our website (www.horizonpharma.com) on or before April 11, 2017.2018.  Since we are an Irish company, we are required to prepare Irish statutory financial statements under applicable Irish company law and to deliver those accounts to shareholders of record in connection with our Annual General Meetings of Shareholders.  The Irish statutory financial statements cover the results of operations and financial position of Horizon Pharma plc for the year ended December 31, 2016.2017.  Irish law requires the directors to prepare financial statements for each financial year giving a true and fair view of the state of the group’s and parent company’s affairs at the end of the financial year and of the group’s profit or loss for the financial year.  Under that law, the directors have prepared the group’s consolidated financial statements in accordance with U.S. generally accepted accounting principles,standards, as defined in Section 279 of the Irish Companies Act 2014, to the extent that the use of those principlesaccounting standards in the preparation of the consolidated financial statements does not contravene any provision of the Irish Companies Act 2014 or of any regulations made thereunder and have prepared the parent companyIrish statutory financial statements in accordance with accounting standards issued by the Financial Reporting Council and promulgated by the Institute of Chartered Accountants in Ireland (Generally Accepted Accounting Practice in Ireland).

We will mail without charge, upon written request, a copy of the Irish statutory financial statements to shareholders of record or beneficial owners of our ordinary shares.  Requests should be sent to:  Horizon Pharma plc, Attention:  Company Secretary, Connaught House, 1^st Floor, 1 Burlington Road, Dublin 4, D04 C5Y6, Ireland.

What proxy materials are available on the internet?

The Proxy Statement and the Annual Report to shareholders are available atwww.edocumentview.com/hznp.

PROPOSAL 1

ELECTION OF DIRECTORS

The Board is divided into three classes.  Each class consists, as nearly as possible, ofone-third of the total number of directors and each class has a three-year term.  The Board currently consists of eightnine members, (but will be decreased to seven members as described below), as follows:

The authorized number of directors may be changed only by resolution of the Board.  Any additional directorships resulting from an increase in the number of directors will be distributed between the three classes so that, as nearly as possible, each class will consist ofone-third of the directors.  This classification of the Board may have the effect of delaying or preventing changes in our control or management.  Our directors may be removed by ordinary resolution with majority vote of the Company’sour shareholders at a general meeting provided that notice of such resolution has been given in accordance with Section 146 of the Irish Companies Act 2014.  Vacancies on the Board may be filled only by persons elected by a majority of the directors then in office, provided that a quorum is present.  A director elected by the Board to fill a vacancy in a class, including vacancies created by an increase in the number of directors, shall serve for the remainder of the full term of that class and until the director’s successor is duly elected and qualified.

There are currently three directors in Class IIII whose term of office expires in 2017, one of whom, Virinder Nohria, M.D., Ph.D., will not be subject tore-election at the 2017 Annual General Meeting. In connection with such director’s term expiring, the authorized size of the Board will be decreased to seven members.2018.  Each of the nominees listed below in Class IIII is currently a directorone of the Companyour directors who was nominated for election by the Board, upon the recommendation of the Nominating and Corporate Governance Committee.  In order to be elected as a director, each nominee must receive the affirmative vote of a majority of the votes cast by the holders of ordinary shares represented at the Annual General Meeting in person or by proxy.  If elected, each of these nominees would serve until the 20202021 Annual General Meeting of Shareholders and until his or her successor has been duly elected and qualified, or, if sooner, until the director’s death, resignation, disqualification or removal.

Gino Santini,William F. Daniel, age 6066

Director since March 2012September 2014

Committee Member:  Audit (Chair), Compensation Transaction (Chair)

Mr. SantiniDaniel, a chartered director and chartered accountant, is currently serves as the chairmana member of the board of directors of AMAG Pharmaceuticals, Inc., aMalin Corporation plc, an Irish-based public biopharmaceutical company,global life sciences company.  Mr. Daniel was president of the Institute of Directors of Ireland from May 2013 to May 2015, and serves onwas originally elected to the board of directorsthe Institute of Intercept Pharmaceuticals, Inc.Directors in Ireland in June 2010.  Prior to that, Mr. Daniel was executive vice president and Collegium Pharmaceutical, Inc., each a public biopharmaceutical company. Mr. Santini serves on the boardcompany secretary of directors of Allena Pharmaceuticals, Inc., Artax Biopharma Inc. and Intarcia Therapeutics, Inc., each a private biopharmaceutical company, and is retired from a distinguished career with Eli Lilly and Company, a public pharmaceutical company. Mr. Santini previously served on the board of directors of Sorin SpA, a public medical products group, from 2012 to 2015, when it was acquired by LivaNova PLC and Vitae Pharmaceuticals, Inc.,Elan Corporation plc, a public biotechnology company, and served in that role from 2014 to 2016. During his tenure at Eli Lilly and Company from June 1983December 2001 to December 2010,2013, until the merger of Elan with Perrigo Company plc.  He was previously an executive director of Elan between 2003 and 2007, having joined the organization as financial controller in 1994.  Mr. Santini held various leadership positions. Mr. Santini, fluent in four languages, holds an undergraduateDaniel graduated with a degree in mechanical engineeringcommerce from the University of Bologna and a master’s degree in business administration from the University of Rochester.College Dublin. 

The Nominating and Corporate Governance Committee and the Board believe that Mr. Santini’s extensive internationalDaniel is qualified to serve as a director of the Company on the basis of his valuable financial and domestic commercial and business development experiencecorporate governance expertise, which brings important strategic insight to the Board as it plans the Company’sour future growth.

Timothy P. Walbert,H. Thomas Watkins, age 5065

Chairman of the Board since March 2010, Director since June 2008April 2014

Committee Member:  NoneAudit, Nominating and Corporate Governance (Chair)

Mr. Walbert has served as ourWatkins, in his most recent role, was director, president and chief executive officer since June 2008 and has served as the chairman of our Board since March 2010. From May 2007 to June 2009, Mr. Walbert served as president, chief executive officer and director of IDM Pharma,Human Genome Sciences, Inc. (HGS), a public biopharmaceutical company, whichfrom 2004 until HGS was acquired by GlaxoSmithKline in 2012.  Before leading HGS, Mr. Watkins spent over twenty years in senior roles at Abbott Laboratories and its affiliates in the United States and Asia, most recently serving as the president of TAP Pharmaceutical Products, Inc. (TAP), which was jointly owned by Abbott and Takeda America Holdings,Pharmaceutical Company, Inc.  in June 2009. Prior to that, Mr. Walbert served as executive vice president, commercial operations of NeoPharm, Inc., a public biopharmaceutical company. From June 2001 to August 2005, Mr. Walbert served as divisional vice president and general manager, Immunology, whereDuring his tenure, he led the global developmentgrowth of TAP from approximately $2 billion to over $4 billion in annual revenue.  Mr. Watkins began his career in 1974 with Arthur Andersen & Co.  From 1979 to 1985, he was a management

consultant with McKinsey and launchCompany, Inc., working with multinational companies in the United States, Europe and Japan.  Mr. Watkins holds a bachelor’s degree from the College of William and Mary, and a master’s degree in business administration from the multi-indication biologic HUMIRA and divisional vice president, global cardiovascular strategy at Abbott, now AbbVie.University of Chicago Graduate School of Business.  Mr. Walbert also serves asWatkins is the chairman of the board of Egalet Corporation,directors of Vanda Pharmaceuticals, Inc., a public pharmaceutical company, and sits onbiotechnology company.  He is also a member of the board of directors of Sucampo Pharmaceuticals, Inc.,HemoShear Therapeutics, LLC, a public biopharmaceutical company. Mr. Walbert serves as Chairman ofprivate biotechnology company, and the Illinois Biotechnology Innovation Organization (iBio)(BIO) and sits onis vice-chair of the board of directorsvisitors of the Pharmaceutical ResearchThe College of William and Manufacturers of America (PhRMA), Biotechnology Innovation Organization (BIO), World Business Chicago (WBC) and the Greater Chicago Arthritis Foundation. Mr. Walbert previously served on the board of directors of Raptor, a public biopharmaceutical company, from 2010 to 2014, and XOMA Corporation, a public biotechnology company, from 2010 to 2017. Mr. Walbert received his bachelor of arts degree in business from Muhlenberg College, in Allentown, Pennsylvania.Mary. 

The Nominating and Corporate Governance Committee and the Board believe that Mr. WalbertWatkins is qualified to serve as a director of the Company on the basis of his valuable industry experience, which brings important strategic insight to the Board as it plans the Company’sour future growth.

Pascale Witz, age 51

Director since August 2017

Committee Member:  Audit, Nominating and Corporate Governance

Ms. Witz founded PWH Advisors, a strategic consultancy firm advising healthcare and investment companies, in November 2016 and has served as its president since that time. From September 2015 to May 2016, Ms. Witz served as executive vice president, global diabetes and cardiovascular at Sanofi, a pharmaceutical company.  During her tenure at Sanofi, she launched multiple medicines across three continents and strengthened the pipeline through licensing and partnerships.  Prior to joining Sanofi, Ms. Witz served more than 17 years at GE Healthcare where, in her final role as president and chief executive officer of its medical diagnostics business, she ran a $2 billion integrated pharmaceutical organization that encompassed research and development through commercial.  Ms. Witz received her Master of Business Administration in Economics and Marketing from INSEAD and her master of science in biochemistry from INSA Lyon.  Ms. Witz also serves on the boards of directors of Fresenius Medical Care AG & Co. KGaA, a public medical supply company, Regulus Therapeutics, a public biotechnology company, PerkinElmer, a public company focused on human and environmental health, and Savencia SA, a public food and dairy company.

The Nominating and Corporate Governance Committee and the Board believe that Ms. Witz is qualified to serve as a director of the Company on the basis of her valuable industry experience, which brings important strategic insight to the Board as it plans our future growth. 

THE BOARD RECOMMENDS

A VOTE IN FAVOR OF EACH NAMED NOMINEE

William F. Daniel, age 64

Director since September 2014

Committee Member: Audit (Chair), Compensation

Mr. Daniel, a Chartered Director and Chartered Accountant, is currently a member of the board of directors of Malin Corporation plc, an Irish-based public global life sciences company. Mr. Daniel was President of the Institute of Directors of Ireland from May 2013 to May 2015, and was originally elected to the board of the Institute of Directors in Ireland in June 2010. Mr. Daniel was Executive Vice President and Company Secretary of Elan Corporation plc, a public biotechnology company, and served in that role from December 2001 to December 2013, until the merger of Elan with Perrigo Company plc. He was previously an Executive Director of Elan between 2003 and 2007, having joined the organization as Financial Controller in 1994. He was also a former President of the Financial Executives’ Association of Ireland. Mr. Daniel graduated with a degree in Commerce from the University College Dublin.

The Nominating and Corporate Governance Committee and the Board believe that Mr. Daniel is qualified to serve as a director of the Company on the basis of his valuable financial and corporate governance expertise, which brings important strategic insight to the Boards as it plans the Company’s future growth.

H. Thomas Watkins, age 64

Director since April 2014

Committee Member: Nominating and Corporate Governance (Chair), Transaction

Mr. Watkins has served as chairman of the board of directors of Vanda Pharmaceuticals Inc., a public biopharmaceutical company, since March 2014. Prior to that, Mr. Watkins was the president and chief executive officer and a director of Human Genome Sciences (HGS), a public biopharmaceutical company, from 2004 until HGS was acquired by GlaxoSmithKline in 2012. Before leading HGS, Mr. Watkins spent over twenty years in senior roles at Abbott Laboratories and its affiliates in the United States and Asia, most recently serving as the president of TAP Pharmaceutical Products, Inc. (TAP), which was jointly owned by Abbott and Takeda Pharmaceutical Company, Inc. During his tenure, he led the growth of TAP from approximately $2 billion to over $4 billion in annual revenue. Mr. Watkins began his career in 1974 with Arthur Andersen & Co. From 1979 to 1985, he was a management consultant with McKinsey and Company, Inc., working with multinational companies in the United States, Europe and Japan. Mr. Watkins holds a bachelor’s degree from the College of William and Mary, and a master’s degree in business administration from the University of Chicago Graduate School of Business. Mr. Watkins is also a member of the board of directors of BIO and a member of the board of visitors of The College of William and Mary.

The Nominating and Corporate Governance Committee and the Board believe that Mr. Watkins is qualified to serve as a director of the Company on the basis of his valuable industry experience, which brings important strategic insight to the Board as it plans the Company’s future growth.

Michael Grey, age 6465

Lead Independent Director since August 2012, Director since September 2011

Committee Member:  Audit, Nominating and Corporate Governance, Transaction

Mr. Grey has served as the executive chairman of Amplyx Pharmaceuticals, Inc. (Amplyx), a private pharmaceutical company, since January 2017; Reneo Pharmaceuticals, Inc. (Reneo), a private pharmaceutical company, since December 2017; and Spruce Biosciences, Inc., a private biotechnology company, since January 2017, as chairman and chief executive officer of Reneo Pharmaceuticals, a biotechnology company that heco-founded, since September 2014 andApril 2017.  He has also served as a venture partner at Pappas Ventures since January 2010.  FromMr. Grey served from October 2015 to December 2016, Mr. Grey servedJanuary 2017 as the president and chief executive officer of Amplyx, and from September 2014 to December 2017 as chairman and chief executive officer of Reneo.  From February 2011 to June 2014, Mr. Grey served as president and chief executive officer of Lumena Pharmaceuticals, Inc., a biotechnology company, which was acquired by Shire plc in June 2014.  Mr. Grey has 40 years of experience in the pharmaceutical and biotechnology industries and has held senior positions at a number of companies, including president and chief executive officer of SGX Pharmaceuticals, Inc. (sold to Eli Lilly and Company in 2008), president and chief executive officer of Trega Biosciences, Inc. (sold to LION Bioscience, Inc. in 2001) and president of BioChem Therapeutic Inc.  Prior to these, Mr. Grey served in various roles with Glaxo, Inc. and Glaxo Holdings PLC, culminating in his position as vice president, corporate development and director of international licensing.  Mr. Grey also serves on the boardboards of directors of BioMarin Pharmaceutical Inc. and Mirati Therapeutics Inc., each aboth public biopharmaceutical company, and on the board of directors of Amplyx, Balance Therapeutics, Inc.biotechnology companies and Biothera Pharmaceuticals, Inc., a private biotechnology company.  Mr. Grey received a bachelor of science degree in chemistry from the University of Nottingham in the United Kingdom.

The Nominating and Corporate Governance Committee and the Board believe that Mr. Grey is qualified to serve as a director of the Company on the basis of his extensive experience managing pharmaceutical and biopharmaceutical companies, which brings important strategic insight to the Board as it plans the Company’sour future growth.

Jeff Himawan, Ph.D., age 5152

Director since July 2007

Committee Member:  Compensation (Chair), Transaction

Dr. Himawan has been a managing director of Essex Woodlands Health Ventures, a venture capital firm, since 2003, where he joined as a partner in 1999.2004.  Prior to that, he was an adjunct partner at Essex Woodlands from 1999 to 2001, and he was a venture partner from 2001 to 2004.  Dr. Himawanco-foundedSeed-One Ventures, an early-stage venture capital firm, where he served as a managing director from 1996 to 1999.2001.  Dr. Himawan also currently serves on the board of directors of Catalyst Biosciences, Inc. and MediciNova, Inc., each a public biopharmaceutical company, and on the board of directors of Light Sciences Oncology, Inc. and OMT Therapeutics, Inc. Dr. Himawan received a bachelor of science degree in biology from the Massachusetts Institute of Technology and his doctorate in biological chemistry and molecular pharmacology from Harvard University.

The Nominating and Corporate Governance Committee and the Board believe that, with his doctorate in biological chemistry and molecular pharmacology and as a successful venture capitalist, Dr. Himawan brings important scientific and strategic insight to the Board as well as experience working with the investment community.

Ronald Pauli, age 5657

Director since September 2011

Committee Member:  Audit, Nominating and Corporate Governance

Mr. Pauli has served as chief financial officer of BioQ Pharma, Inc., a private specialty pharmaceutical company, since August 2014.  Prior to that, Mr. Pauli was an independent financial consultant to the pharmaceutical industry from September 2012 to July 2014 and held senior positions at a number of biopharmaceutical companies, including chief financial officer at Sagent Pharmaceuticals, Inc. from April 2007 to August 2012, chief financial officer at NeoPharm, Inc. from 2006 to 2007 and corporate controller and interim chief financial officer at Abraxis BioScience, Inc. (formerly American Pharmaceutical Partners, Inc.) from 2002 to 2006.  In addition, Mr. Pauli previously served as corporate controller for Applied Power, Inc. and R.P.  Scherer Corporation, held multiple finance positions at Kmart Corporation and began his career with Ernst & Whinney.  Mr. Pauli received a bachelor of science degree in accounting from Michigan State University and a master’s degree in finance from Walsh College.

The Nominating and Corporate Governance Committee and the Board believe that Mr. Pauli is qualified to serve as a director of the Company on the basis of his financial experience at numerous biotechnology and pharmaceutical companies, which adds valuable expertise in guiding theour strategic direction of the Company and working with the investment community.

Gino Santini, age 61

Director since March 2012

Committee Member:  Compensation, Transaction (Chair)

Mr. Santini currently serves as the chairman of the board of directors of AMAG Pharmaceuticals, Inc., a public biopharmaceutical company, and serves on the board of directors of Intercept Pharmaceuticals, Inc., Collegium Pharmaceutical, Inc. and Allena Pharmaceuticals, Inc., all of which are public biopharmaceutical companies.  Mr. Santini also serves on the board of directors of Artax Biopharma Inc. and Intarcia Therapeutics, Inc., each a private biopharmaceutical company, and is retired from a distinguished career with Eli Lilly and Company, a public pharmaceutical company.  Mr. Santini previously served on the board of directors of Sorin SpA, a public medical products group, from 2012 to 2015, when it was acquired by LivaNova PLC and Vitae Pharmaceuticals, Inc., a public biotechnology company, from 2014 to 2016, when it was acquired by Allergan plc.  During his tenure at Eli Lilly and Company from June 1983 to December 2010, Mr. Santini held various leadership positions.  Mr. Santini, fluent in four languages, holds an undergraduate degree in mechanical engineering from the University of Bologna and a master’s degree in business administration from the University of Rochester. 

The Nominating and Corporate Governance Committee and the Board believe that Mr. Santini’s extensive international and domestic commercial and business development experience brings important insight to the Board as it plans our future growth. 

James Shannon, M.D., age 61

Director since August 2017

Committee Member:  Compensation, Transaction

Dr. Shannon currently serves on the board of directors for MannKind Corporation, a public biopharmaceutical company focused on treatments for diabetes.  From May 2012 to March 2015, Dr. Shannon served as the chief medical officer of GlaxoSmithKline (GSK), a public biopharmaceutical company, where he was responsible for matters of patient safety, general medical governance,

medical ethics and integrity, medical information as well as investigations involving human subjects relating to any GSK medicine in development or on the market.  Prior to that, Dr. Shannon spent more than a decade with Novartis, a public pharmaceutical company.  In his last role with the company, as global head of pharma development, he was responsible for all of Novartis’s development activities, frompre-clinical through Phase 4 and oversaw an annual development budget of approximately $4 billion.  Dr. Shannon received his science and medical degrees from Queen’s University in Belfast, Northern Ireland.  In addition to MannKind Corporation, he serves on the board of directors of ProQR Therapeutics NV, a public therapeutics company; Immodulon Therapeutics Limited, a private biopharmaceutical company; and MyTomorrows, a health-based platform that collaborates with drug developers to provide early access to treatments for patients who have exhausted all other options. 

The Nominating and Corporate Governance Committee and the Board believe that Dr. Shannon is qualified to serve as a director of the Company on the basis of his extensive clinical development experience, which brings important insight to the Board as it plans our future growth. 

Timothy P. Walbert, age 51

Chairman of the Board since March 2010, Director since June 2008

Committee Member:  None

Mr. Walbert has served as our president, chief executive officer and director of the Company since June 2008 and served as our chairman since March 2010.  From May 2007 to June 2009, Mr. Walbert served as president, chief executive officer and director of IDM Pharma, Inc., a public biopharmaceutical company that was acquired by Takeda America Holdings, Inc. in June 2009.  Prior to that, Mr. Walbert served as executive vice president, commercial operations of NeoPharm, Inc., a public biopharmaceutical company.  From June 2001 to August 2005, Mr. Walbert served as divisional vice president and general manager of immunology, where he built and led the global development and launch of the multi-indication biologic HUMIRA and divisional vice president, global cardiovascular strategy at Abbott, now AbbVie.  Mr. Walbert also serves as chairman of the board of directors of Egalet Corporation, a public pharmaceutical company.  Mr. Walbert sits on the board of directors of the Illinois Biotechnology Innovation Organization (iBIO), the Biotechnology Innovation Organization (BIO), World Business Chicago (WBC) and the Greater Chicago Arthritis Foundation.  Mr. Walbert is also a member of the Illinois Innovation Council.  Mr. Walbert previously served on the board of directors of Raptor Pharmaceutical Corp. (Raptor), a public biopharmaceutical company, from 2010 to 2014; XOMA Corporation, a public biotechnology company, from 2010 to 2017; and Sucampo Pharmaceuticals, Inc., a public biopharmaceutical company, from March 2016 to February 2018.  Mr. Walbert received his bachelor of arts degree in business from Muhlenberg College, in Allentown, Pennsylvania. 

The Nominating and Corporate Governance Committee and the Board believe that Mr. Walbert is qualified to serve as a director of the Company on the basis of his valuable industry experience, which brings important strategic insight to the Board as it plans our future growth. 

THE BOARD OF DIRECTORS AND ITS COMMITTEES

In 2016,2017, the Board held seven meetings and did not act by unanimous written consent without a meeting.  Each Board member attended 7594 percent or more of the aggregate number of meetings of the Board and of the committees on which he or she served.  It is the Company’sour policy to encourage directors and nominees for director to attend annual general meetings of shareholders.  AllWith the exception of Dr. Shannon and Ms. Witz, both of whom were appointed to the Company’sBoard in August 2017, all of our current directors attended its 2016our 2017 Annual General Meeting of Shareholders.

The Board is committed to exercising good corporate governance practices.  As part of this commitment, the Board regularly monitors developments in the area of corporate governance and reviews processes, policies and procedures in light of such developments.  Key information regarding our corporate governance initiatives can be found on Horizon Pharma’sour website,www.horizonpharma.com, including our Memorandum and Articles of Association, Code of Business Conduct and Ethics, and the charters for the Audit, Compensation, Nominating and Corporate Governance and Transaction Committees.  The Board believes that its strong corporate governance policies and practices, including the substantial percentage of independent directors on the Board and the robust duties of its lead independent director, empower the Board to effectively oversee the Company’sour Chief Executive Officer and provide an effective and appropriately balanced boardBoard governance structure.

Seventy-five percent of theOther than Mr. Walbert, our chairman, president and chief executive officer, all members of the Board are independent and all members of committees of the Board are independent.  The Board has affirmatively determined that the following sixeight directors

are independent directors within the meaning of the applicable NASDAQNasdaq Stock Market (NASDAQ)(Nasdaq) listing standards:  Mr. Daniel, Mr. Grey, Dr. Himawan, Mr. Pauli, Mr. Santini, Dr. Shannon, Mr. Watkins and Mr. Watkins.Ms. Witz.  In making this determination, the Board found that none of these directors or nominees for director had a material or other disqualifying relationship with the Company.us. Mr. Walbert the Company’s President and Chief Executive Officer, and Dr. Nohria, a prior employee of Vidara Therapeutics International Public Limited Company (Vidara), areis not an independent directorsdirector by virtue of theirhis current and prior employment with the Company, respectively.us.  To determine independence, the Board reviewed all relevant identified transactions or relationships between each director, or any of his or her family members, and the Company, itsus, our senior management and itsour independent registered public accounting firm.

As required under applicable NASDAQNasdaq listing standards, in fiscal year 2016, the Company’s2017, our independent directors met four times in regularly scheduled executive sessions at which only independent directors were present.

The Company hasWe have adopted a Code of Business Conduct and Ethics (the Code) that applies to all officers, directors and employees, including the Company’sour principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions.  The Code is available on the Company’sour website atwww.horizonpharma.com.  If the Company makes any substantive amendments to the Code or grants any waiver from a provision of the Code to any executive officer or director, the Company will promptly disclose the nature of the amendment or waiver on its website or in a current report on Form8-K.

The Board has determined that the current leadership structure, in which the offices of Chairman and Chief Executive Officer are held by one individual and an independent director acts as lead independent director, ensures that the appropriate level of oversight, independence, and responsibility is applied to all Board decisions, including risk oversight, and is in theour best interests and those of Horizon Pharma and itsour shareholders.

Chairman/Chief Executive Officer

The Board is currently chaired by the President and Chief Executive Officer of the Company, Mr. Walbert.  The Company believes that combining the positions of Chief Executive Officer and Chairman of the Board helps to ensure that the Board and management act with a common purpose for the following reasons:

Lead Independent Director

The Company requires the election, by the independent directors of the Board, of a lead independent director to serve during any period when there is no independent Chairman of the Board.  Because Mr. Walbert is currently serving as Chief Executive Officer and Chairman of the Board, the independent directors of the Board elected Mr. Grey as the lead independent director.  The lead independent director serves as the liaison between the Chairman of the Board and the independent directors and his responsibilities include:

One of the Board’s key functions is informed oversight of the Company’sour risk management process.  The Board does not have a standing risk management committee, but rather administers this oversight function directly through the Board as a whole, as well as through various Board standing committees that address risks inherent in their respective areas of oversight.  In particular, the Board is responsible for monitoring and assessing strategic risk exposure, including a determination of the nature and level of risk appropriate for the Company.  Our Audit Committee has the responsibility to consider and discuss our major financial risk exposures and the steps our management has taken to monitor and control these exposures, including guidelines and policies to govern the process by which risk assessment and management is undertaken and provides oversight of the performance of our internal audit function and external auditors.  Our Nominating and Corporate Governance Committee monitors the effectiveness of our corporate governance guidelines, including whether they are successful in preventing illegal or improper liability-creating conduct, and monitors compliance with legal, regulatory and ethical requirements.  Our Compensation Committee assesses and monitors whether any of our compensation policies and programs has the potential to encourage excessive risk-taking.  Our Transaction Committee evaluates potential strategic transactions and financing opportunities, including the risks that such transactions could pose to the Company.

The Nominating and Corporate Governance Committee will consider candidates for the Board who are recommended by shareholders, directors, third-party search firms engaged by the Board and other sources.  When selecting candidates for recommendation to the Board, the Nominating and Corporate Governance Committee will consider the attributes of the candidates and the needs of the Board and will review all candidates in the same manner, regardless of the source of the recommendation.  In evaluating director nominees, a candidate should have certain minimum qualifications, including being able to read and understand basic financial statements, having familiarity with our business and industry, having high moral character and mature judgment and being able to work collegially with others.  In addition, factors such as the following may be considered:

The Nominating and Corporate Governance Committee believes in an expansive definition of diversity that includes differences of experience, education, talents, gender and talents, among other things.race.  While the Nominating and Corporate Governance Committee does not have a formal policy in this regard, the diversity of the Board is listed as a factor to be considered in evaluating candidates for the Board, among others, in the Nominating and Corporate Governance Committee Charter, which is available on our website atwww.horizonpharma.com.

Shareholders who wish to recommend individuals for consideration by the Nominating and Corporate Governance Committee to become nominees for election to the Board at an Annual General Meeting of Shareholders must do so by delivering a written recommendation to the Nominating and Corporate Governance Committee.  See “Other Information –Shareholder— Shareholder Proposals” in this Proxy Statement for additional information.

The Board has four standing committees:  the Audit Committee, Compensation Committee, Nominating and Corporate Governance Committee and Transaction Committee.  All committees are comprised of independent directors within the meaning of the applicable NASDAQNasdaq listing standards.  A description of each committee of the Board is described below. 

The following table provides membership and meeting information for fiscal year 20162017 for each of the Board committees:

Audit(1)

Nominating and        Corporate Governance(2)

Compensation(3)

Transaction(4)

Timothy P. Walbert

Michael Grey

William F. Daniel

Jeff Himawan, Ph.D.

Virinder Nohria, M.D., Ph.D.(5)

Ronald Pauli

Gino Santini

H. Thomas Watkins

Total meetings in fiscal year 2016

7

4

7

8

		Audit(1)		Compensation(2)		Nominating and        Corporate Governance(3)		Transaction(4)
Timothy P. Walbert
Michael Grey(5)
William F. Daniel(6)
Jeff Himawan, Ph.D.(7)
Virinder Nohria, M.D. Ph.D.(8)
Ronald Pauli(9)
Gino Santini(10)
James Shannon, M.D.(11)
H. Thomas Watkins(12)
Pascale Witz(13)
Total meetings in fiscal year 2017		5		6		4		8

 

= Chair		= Member		= Lead Independent Director

 

(1)	Effective as of February 2017,2018, the Audit Committee consists of Mr. Daniel, Mr. GreyPauli, Mr. Watkins and Mr. Pauli,Ms. Witz, with Mr. Daniel serving as the chair.

(2)	Effective as of February 2017,2018, the Compensation Committee consists of Mr. Daniel, Dr. Himawan, Mr. Santini and Dr. Shannon, with Dr. Himawan serving as the chair.

(3)	Effective as of February 2018, the Nominating and Corporate Governance Committee consists of Mr. Grey, Mr. Pauli, and Mr. Watkins and Ms. Witz, with Mr. Watkins serving as the chair.

(3)	Effective as of February 2017, the Compensation Committee consists of Mr. Daniel, Dr. Himawan and Mr. Santini, with Dr. Himawan serving as the chair.

(4)	Effective as of FebruaryAugust 2017, the Transaction Committee consists of Mr. Grey, Dr. Himawan, Mr. Grey, Mr. Santini and Mr. Watkins,Dr. Shannon, with Mr. Santini serving as the chair.

(5)	Mr. Grey served on the Audit Committee from February 2017 until August 2017, served on the Compensation Committee until February 2017 and has served on the Nominating and Corporate Governance Committee since February 2017.

(6)	Mr. Daniel has served as the chair of the Audit Committee and on the Compensation Committee since February 2017 and served on the Nominating and Corporate Governance Committee until February 2017.

(7)	Dr. Himawan served on the Audit Committee until February 2017 and has served on the Transaction Committee since February 2017.

(8)	Dr. Nohria will not be subject tore-election atserved on the Board until May 2017.

(9)

Mr. Pauli served as the chair of the Audit Committee and on the Compensation Committee until February 2017.  He served on the Nominating and Corporate Governance Committee from February 2017 Annual General Meeting.until August 2017 and rejoined the Nominating and Corporate Governance Committee in February 2018.

(10)	Mr. Santini has served on the Compensation Committee since February 2017 and served on the Nominating and Corporate Governance Committee until February 2017.

(11)	Dr. Shannon has served on the Transaction Committee since joining the Board in August 2017.  He joined the Compensation Committee in February 2018.

(12)	Mr. Watkins served on the Transaction Committee until August of 2017.  He has served on the Audit Committee since August 2017.

(13)	Ms. Witz has served on the Nominating and Corporate Governance Committee since joining the Board in August 2017.  She joined the Audit Committee in February 2018.

 

Audit Committee

The Audit Committee assists the Board in fulfilling its oversight responsibility with respect to, Horizon Pharma’samong other things:  (i) our corporate accounting and financial reporting practices, (ii) the system of internal control over financial reporting, (iii) the audit process, (iv) the quality and integrity of Horizon Pharma’sour financial statements, (v) the independent auditors’ qualifications, independence and performance of our independent registered public accounting firm, (vi) the qualifications, independence and performance of Horizon Pharma’sour internal audit function and external auditors and(vii) enterprise risk management.  Each of the independent registered public accounting firm, internal audit and management periodically meet privately with the Audit Committee.

The Board has determined that each of Mr. PauliDaniel and Mr. DanielPauli qualify as an “audit committee financial expert,” within the meaning of Securities and Exchange Commission (SEC) regulations and the NASDAQNasdaq Listing Rules.  In making this determination, the Board has considered (i) with respect to Mr. Pauli, his formal education and the nature and scope of his previous experience, coupled with past and present service on various audit committees and (ii) with respect to(i) Mr. Daniel, his formal education, the nature and scope of his previous experience and his financial and

corporate governance expertise, and (ii) Mr. Pauli, his formal education, the nature and scope of his previous experience and his financial expertise.

Report of the Audit Committee of the Board of Directors

The material in this report is not “soliciting material,” is not deemed “filed” with the SEC and is not to be incorporated by reference in any filing of the Companyour filings under the Securities Act of 1933, as amended (the Securities Act), or the Securities Exchange Act of 1934, as amended (Exchange Act), whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

The Audit Committee has reviewed and discussed the audited financial statements for the fiscal year ended December 31, 20162017 with management of the Company.  The Audit Committee has discussed with the independent registered public accounting firm the matters required to be discussed by Auditing Standard No.  16,1301, Communications with Audit Committees,, as adopted by the Public Company Accounting Oversight Board (PCAOB).  The Audit Committee has also received the written disclosures and the letter from the independent registered public accounting firm required by applicable requirements of the PCAOB regarding the independent registered public accounting firm’s communications with the Audit Committee concerning independence, and has discussed with the independent registered public accounting firm the accounting firm’s independence.  Based on the foregoing, the Audit Committee has recommended to the Board of Directors that the audited financial statements be included in the Company’s Annual Report on FormForm 10-K for the fiscal year ended December 31, 2016.2017. 

Audit Committee

Ronald Pauli,William F. Daniel,Chairman

William F. DanielRonald Pauli

Jeff Himawan, Ph.D.H. Thomas Watkins

Compensation Committee

The Compensation Committee oversees, reviews and approves or recommends for adoption the Company’sour compensation policies, plans and programs, determinesreviews and approves or approves,recommends to the full Board, as appropriate, the compensation to be paid to itsour executive officers and directors, and prepares and reviews the Compensation Committee report included in our annual proxy statement.  In making its compensation decisions and recommendations, the Compensation Committee may take into account the recommendations of the Chief Executive Officer and other senior management.  Other than giving such recommendations, however, the Chief Executive Officer and other senior management have no formal role and no authority to determine the amount or form of executive and director compensation.  The processes and procedures used for the consideration and determination of executive compensation are described in the section of this Proxy Statement captioned, ‘‘Compensation Discussion and Analysis.’’

The Compensation Committee may, at theour expense, of the Company, retain legal counsel (which may, but need not be, theour regular corporate counsel to the Company)counsel) and other consultants and advisors, other thanin-house legal counsel and certain other types of advisors, to assist it with its functions only after taking into consideration six factors, prescribed by the SEC and NASDAQ,Nasdaq, that bear upon the advisor’s independence; however, there is no requirement that any advisor be independent.  The Compensation Committee has authority to approve such advisors’ fees and other retention terms and to terminate its relationship with any advisor that it retains.  In addition, the Compensation Committee has authority to delegate its responsibilities to subcommittees or individual committee members.

From January through SeptemberIn October 2016, our Compensation Committee engaged Clearbridge Compensation Group, LLC (Clearbridge) as its independent compensation consultant and beginning in October 2016, the Compensation Committee engaged Radford, an Aon Hewitt Company (Radford), as its independent consultant.  For additional information regarding our processes and procedures for the consideration and determination of executive compensation, including the role of Radford in determining and recommending executive compensation, the aggregate cost of Radford’s executive and director compensation consulting services during 2016,2017, see the section of this Proxy Statement entitled “Compensation Discussion and Analysis—Analysis — Compensation Determination Process.” With respect to director compensation matters, our Compensation Committee recommends to our Board and our Board determines and setsnon-employee director compensation.  Our compensation arrangements for ournon-employee directors are described under the section of this proxy statementProxy Statement entitled“Non-Employee Director Compensation.”

Compensation Committee Interlocks and Insider Participation

No member of our Compensation Committee has ever been an executive officer or employee of the Company.  None of the Company’sour executive officers currently serves, or has served during the last completed year, on the compensation committee or board of directors of any other entity that has one or more officers serving as a member of our Board or Compensation Committee.

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee assistsoversees all aspects of our corporate governance functions on behalf of the Board, in identifying individuals qualifiedincluding, but not limited to, become Board members and recommends(i) making recommendations to the Board the nominees for electionregarding corporate governance issues; (ii) identifying, reviewing and evaluating candidates to serve as directors atof the next annual general meeting of shareholders, recommendsCompany consistent with criteria approved by the Board and reviewing and evaluating incumbent directors; (iii) serving as a focal point for communication between such candidates,non-committee directors and our management; (iv) nominating candidates to serve as directors; (v) making other recommendations to the Board the persons to be appointed as executive officers of Horizon Pharma, develops and recommendsregarding affairs relating to the Board the corporate governance guidelines applicable to Horizon Pharma, serves in an advisory capacity to the Board and the Chairmandirectors of the Board on matters of organization, management succession plans, major changesCompany; and (vi) providing oversight assistance in the organizational structure of Horizon Pharma and the conduct of Board activities, and monitors complianceconnection with our legal, regulatory and ethical requirements.compliance programs, policies and procedures as established by management and the Board. 

The process used by the Nominating and Corporate Governance Committee to identify a nominee to serve as a member of the Board depends on the qualities being sought.  From time to time, the Board engages an executive search firm to assist the Nominating and Corporate Governance Committee in identifying individuals qualified to be Board members.  The process used by the Nominating and Corporate Governance Committee to identify nominees is described in the section of this Proxy Statement captioned, ‘‘Director Selection.’’

Transaction Committee

The functions of the Transaction Committee include, but are not limited to:

Shareholders who wish to communicate with the Board may do so by sending written communications addressed to the Company Secretary of Horizon Pharma at Connaught House, 1^st Floor, 1 Burlington Road, Dublin 4, D04 C5Y6, Ireland or by communicating online to the Board as a group.  This information and an online communications form are available on the Company’sour website atwww.horizonpharma.com.  Each communication will be reviewed by Horizon Pharma’sour Company Secretary to determine whether it is appropriate for presentation to the Board or such director on a periodic basis.  Examples of inappropriate communications include advertisements, solicitations or hostile communications.

EXECUTIVE OFFICERS

The following table sets forth information regarding executive officers as of March 31, 2017:2018:

The following is biographical information as of March 31, 20172018 for our executive officers other than Mr. Walbert, whose biographical information is included above.

Brian K. BeelerBeeler..  Mr. Beeler has served as our executive vice president, general counsel since May 2015.  Mr. Beeler previously served as our senior vice president, legal and chief compliance officer from January 2015 until May 2015 and as our associate general counsel and chief compliance officer from January 2013 until January 2015.  Prior to joining Horizon Pharma, Mr. Beeler served as associate general counsel for Fenwal, Inc., a global blood technology company, from December 2008 until December 2012.  Before that, Mr. Beeler was senior counsel, business development, commercial and research and development at TAP Pharmaceuticals and Takeda Pharmaceuticals North America and also previously served as chief compliance officer at Schwartz Pharma.  Mr. Beeler received a bachelor’s degree in history from Purdue University, an MBAa master’s degree in business administration from the Kellogg School of Management at Northwestern University and a JD from the Indiana University School of Law.

Robert F. CareyCarey..Mr. Carey has served as our executive vice president, chief business officer since March 2014.  Prior to that, Mr. Carey spent more than 11 years as managing director and head of the life sciences investment banking group at JMP Securities LLC, a full-service investment bank.  Prior to JMP, Mr. Carey was a managing director in the healthcare groups at Dresdner Kleinwort Wasserstein and Vector Securities.  Mr. Carey also has held roles at Red Hen Bread, InStadium, Shearson Lehman Hutton and Ernst & Whinney.  Mr. Carey serves on the board of directors of Argos Therapeutics Inc. and Sangamo Therapeutics, Inc., each a public pharmaceutical company.  Mr. Carey received his bachelor of science degree in accounting from the University of Notre Dame.

Michael A. DesJardin.  Mr. DesJardin has served as our executive vice president, technical operations since February 2017.  Mr. DesJardin previously served as our senior vice president, technical operations from October 2016 to November 2016 and as our senior vice president, life cycle management from December 2016 to January 2017.  Prior to joiningMr. DesJardin joined Horizon Pharma from Raptor in October 2016 as part of the Raptor acquisition.  While at Raptor, Mr. DesJardin was the senior vice president of technical operations at Raptor from April 2015 to October 2016.  Prior to that, Mr. DesJardin served as senior vice president of product development at Jazz Pharmaceuticals Public Limited Company (formerly Jazz Pharmaceuticals, Inc.) (Jazz) from July 2004 to March 2015.  Mr. DesJardin spent nine years as an executive director and engineering fellow at ALZA Corporation and spent 15 years at the DOWDow Chemical Company working in pharmaceutical and agricultural chemical development for Marion Merrill Dow.  Mr. DesJardin has over 35 years of experience in pharmaceutical development.  Mr. DesJardin received a bachelor of science degree in chemical engineering from the University of California, Berkeley and is a registered professional engineer in the State of California.

George P. HamptonHampton..  Mr. Hampton has served as our executive vice president, primary care business unit since October 2016.  Previously, Mr. Hampton served as our executive vice president, orphan and primary care business units and international operations from February 2016 to October 2016, as our executive vice president, orphan business unit and international operations from August 2015 to February 2016 and as our group vice president, international operations from April 2015 to August 2015.  Prior to joining Horizon Pharma as a full time employee, Mr. Hampton served as oura consultant to the Company since 2008.  From 2009 until February 2015, Mr. Hampton served as president and chief executive officer of Global Village Concerns, a privately held technology company.  Mr. Hampton has more than 20 years of experience as an executive in the pharmaceutical and biotechbiotechnology industries on both a national and international scale including specific expertise in the autoimmune, primary care, orthopedic, diabetes, anti-infectives and cardiovascular areas.  Mr. Hampton holds a bachelor of science degree from Miami University in Oxford, Ohio.

Paul W. Hoelscher.Mr. Hoelscher has served as our executive vice president, chief financial officer since October 2014.  Previously, Mr. Hoelscher was our executive vice president, finance from June 2014 through September 2014.  Prior to joining Horizon Pharma, Mr. Hoelscher served as senior vice president, finance — treasuryfinance-treasury and corporate development of OfficeMax, Inc., from August 2013 to May 2014, and as vice president, finance — treasuryfinance-treasury and corporate development of OfficeMax from August 2012 to July 2013.  From May 2011 to May 2012, Mr. Hoelscher served as vice president, finance integration of Alberto Culver Company, a beauty care company which was acquired by Unilever in 2011.  Prior to that, Mr. Hoelscher served as vice president, international finance and treasurer from 2010 to May 2011 and vice president, corporate controller from 2004 to 2010.  Mr. Hoelscher also served in various positions in the audit practice at KPMG LLP from 1986 to 1993 and currently serves onas chair of the board of trustees of the Illinois Chapter of the Leukemia and Lymphoma Society.  Mr. Hoelscher received his bachelor of science degree in accountancy from the University of Illinois at Urbana-Champaign and is a certified public accountant.

Vikram Karnani.Karnani.  Mr. Karnani joined Horizon Pharma in July 2014has served as groupour executive vice president, and general manager, specialty business unit and haschief commercial officer since March 2018.  Prior to that, he served as our senior vice president, rheumatology business unit sincefrom February 2017.2017 to March 2018, and before that, from July 2014 until February 2017, he served as our general manager, specialty business unit.  Prior to joining Horizon Pharma, Mr. Karnani was with Fresenius Kabi, a global health care company, where he served as vice president of the therapeutics and cell therapy business, from October 2011 to July 2014.  Mr. Karnani also held various positions in business development, corporate strategy and strategic marketing within Fenwal Inc., a global blood technology company that was acquired by Fresenius Kabi, from November 2008 to October 2011.  Mr. Karnani brings nearly 16 years of cross functionalcross-functional expertise across a multitude of industries, including medical devices, management consulting, semiconductors and cellular telecommunications.  Mr. Karnani has a master’s degree from the Kellogg School of Management at Northwestern University, a master’s degree in electrical engineering from Case Western Reserve University and a bachelor of science degree in electrical engineering from University of Bombay, India.

Irina P. Konstantinovsky.  Ms. Konstantinovsky has served as our executive vice president, chief human resources officer since September 2017.  Prior to Horizon Pharma, from August 2012 to September 2017, she was vice president of global talent at Baxter International Inc., a healthcare products company, where she led a team of talent professionals worldwide and oversaw organizational effectiveness, leadership development, inclusion and diversity and talent acquisition.  She and her team were responsible for talent management strategies, programs and systems for more than 50,000 employees worldwide.  Prior to Baxter, Ms. Konstantinovsky spent 15 years in senior partner and director roles at Towers Watson (currently Willis Towers Watson), a global human resources consulting firm serving Fortune 1000 companies.  While in these roles, she served as the interim chief human resource officer at Capital BlueCross for two years.  Ms. Konstantinovsky has a bachelor of arts in education from the University of Buenos Aires and master’s degrees in higher education and industrial and labor relations from Cornell University.  In addition, she serves on the board of the Human Resource Management Association of Chicago. 

Shao-Lee Lin.  M.D., Ph.D.  Dr. Lin has served as our executive vice president, head of research and development and chief scientific officer since January 2018.  Prior to Horizon Pharma, Dr. Lin was a corporate officer and vice president, therapeutic areas, development excellence and international development at AbbVie, Inc., a pharmaceutical company, from March 2015 to December 2017.  In that role, she led immunology, virology, neuroscience and general medicine, acrosson-market and pipeline compounds as well as international development across all therapeutic areas.  Prior to AbbVie, Dr. Lin was vice president, inflammation and respiratory development at Gilead Sciences, Inc., a biopharmaceutical company, from July 2012 to February 2015.  She also held leadership positions in immunology and other therapeutic areas while at Amgen Inc., a biotechnology company.  Dr. Lin received her medical degree and doctorate at the Johns Hopkins University School of Medicine and completed fellowships and post-doctoral work in rheumatology, allergy and immunology at the University of California San Diego and The Scripps Clinic and Research Institute.  She has a bachelor of science in biochemistry and chemical engineering from Rice University.  Dr. Lin is currently adjunct faculty at Northwestern University.  She has previously been on the faculty of Rockefeller University as a Clinical Scholar and also served as adjunct faculty at Cornell, University of California Los Angeles (UCLA) and Stanford medical schools. 

Eric B. Mosbrooker. Mr. Mosbrooker has served as senior vice president, orphan business unit since August 2017.  Prior to that he was our group vice president and general manager, Americas and Asia Pacific, orphan business unit, from October 2016 to August 2017.  Mr. Mosbrooker joined Horizon Pharma in October 2016 as part of the acquisition of Raptor.  He has 15 years of experience in the healthcare industry, with the majority of his tenure focused on launching and commercializing treatments for rare diseases.  Prior to joining Horizon Pharma, he was at Raptor from November 2012, where he served in various commercial management positions and led the U.S. launch of PROCYSBI.  At the time of the Raptor acquisition, he was senior vice president, Americas and Asia Pacific at Raptor.  Prior to Raptor, Mr. Mosbrooker served as the lead for commercial operations and market access at Enobia Pharma, Inc., a pharmaceutical company.  He also served in increasing leadership roles for commercial operations at Onyx Pharmaceuticals, Jazz Pharmaceuticals Inc., Chiron Corporation and Millennium Pharmaceuticals. 

Mr. Mosbrooker also has extensive experience in management, healthcare and technology consulting through positions at IBM,

Teltech Resource Network Corporation and Kohler Company. Mr. Mosbrooker received a bachelor of science in industrial engineering from the University of Wisconsin.

Barry J. Moze.Mr. Moze has served as our executive vice president, chief administrative officer since February 2017.  Prior to that, Mr. Moze was our executive vice president, chief operating officer from February 2016 to January 2017 and was our executive vice president, corporate development from May 2014 to January 2016.  Prior to joining Horizon Pharma, Mr. Moze spent more than 28 years as a partner of Crystal Clear Communications, a consulting firm focused on the development and execution of corporate strategies.  Prior to Crystal Clear, Mr. Moze was a founder and president of Review Services and Asset Management Group, a licensed investment advisory firm. Mr. Moze serves on the board of directors of Palermo Villa.

Jeffrey W. Sherman, M.D., FACP.Dr. Sherman has served as our executive vice president, chief medical officer since January 2018.  From September 2014 to January 2018, Dr. Sherman served as our executive vice president, research and development and chief medical officer since September 2014.officer.  From June 2011 until September 2014, Dr. Sherman served as our executive vice president, development, manufacturing, and regulatory affairs and chief medical officer and from June 2009 until June 2011, Dr. Sherman served as our executive vice president, development and regulatory affairs and chief medical officer.  From June 2009 to June 2010, Dr. Sherman served as president and board member of the Drug Information Association, a nonprofit professional association of members who work in government regulatory, academia, patient advocacy and the pharmaceutical and medical device industry.  Prior to June 2009, Dr. Sherman held other management roles at IDM Pharma, Inc., Takeda Global Research & Development, NeoPharm, Inc. and G.D.  Searle, LLC/Pharmacia.  He also serves on the board of Strongbridge Biopharma plc, a public global commercial-stage biopharmaceutical company and the Board of Advisors of the Center for Information and Study on Clinical Research Participation, a nonprofit organization dedicated to educating and informing the public, patients, medical/research communities, the media and policy makers about clinical research and the role each party plays in the process.  Dr. Sherman is an adjunct assistant professor of Medicine at the Northwestern University Feinberg School of Medicine and is a member of a number of professional societies as well as a diplomat of the National Board of Medical Examiners and the American Board of Internal Medicine.  Dr. Sherman received his M.D. from the Rosalind Franklin University/Chicago Medical School.  Dr. Sherman completed an internal medicine internship, residency and chief medical residency at Northwestern University as well as fellowship training at the University of California, San Francisco (UCSF).  Dr. Sherman was also a research associate at the Howard Hughes Medical Institute at UCSF.

COMPENSATION DISCUSSION AND ANALYSIS

This Compensation Discussion and Analysis (CD&A) discusses the compensation philosophy, policies and principles underlying our executive compensation decisions made for 20162017 compensation.  This CD&A provides qualitative information on the factors relevant to these decisions and the manner in which compensation is awarded to the following executive officers who have been named in the Summary Compensation Table included in this Proxy Statement and whom we refer to as our named executive officers (NEOs).

Quick CD&A Reference Guide

In 2016, we delivered strong results to create long-term value for our shareholders. We continued tomade significant progress in 2017 on our long-term business strategy of building a more-diversifieddiversified and durable, high-growth biopharmaceutical company anchored by a growing mix offocused on rare disease medicines.  We have grown both organically and through strategic acquisitions and today have 11 medicines across three business units: orphan, rheumatology and primary care.

Strong and Consistent Financial Performance

In 2016, we delivered another record sales year and achieved an important milestone for our company, surpassing $1 billion innon-GAAP adjusted net sales in 2016 following rapid growth and transformation over the last five years. In 2011, for perspective, we generated $7 million in sales in our first year as a publicly traded company.

Note: The 2014 and 2015 totalfull-year net sales of $297 million and $757 million, respectively, represent GAAP$1.06 billion, with our rare disease medicines, now representing approximately 60 percent of our net sales, and the 2016 total net sales of $1,046 million representsnon-GAAP adjusted net sales. On September 26, 2016, Horizon Pharma agreed to pay Express Scripts $65 million as part of a litigation settlement, which was recorded as aone-time reduction to GAAP net sales for the three months ended September 30, 2016, in accordance with GAAP. The exclusion of the $65 million settlement from GAAP net sales is the only adjustment reflected in 2016non-GAAP adjusted net sales.

Diversification and Growth

We’ve accomplished a great deal over the last five years – executing on our organic growth opportunities, evolving our business model and completing six acquisitions that have diversified our company from two medicines in 2013 to 11 medicines in 2016 across three business units: orphan, rheumatology and primary care.

increasing 60 percent year-over-year.  In addition to delivering onexpanding the commercial efforts for our financial commitments,key growth driver KRYSTEXXA, which we continued to shape and transformnow believe has peak net sales potential of more than $750 million, we augmented our pipeline with the addition ofHZN-001 (teprotumumab), a late-stage development fully human monoclonal antibody (mAb) insulin-like growthfactor-1 receptor(IGF-1R) inhibitor candidate for the treatment ofmoderate–to-severe thyroid eye disease (TED), as well as several new rheumatology pipeline programs. 

Our Strategy

Our strategy has evolved over three phases.  When we first launched as a public company in 2016, completing2011, we rapidly established our infrastructure and commercial footprint, generating earnings and cash flow through the commercialization of our first two strategic transactionsmedicines, DUEXIS and RAYOS.  In 2014, we began the second phase of our strategy, which focused on rapid diversification into rare disease medicines through key acquisitions that brought us threeACTIMMUNE, RAVICTI, KRYSTEXXA and PROCYSBI.  In 2017, we began the third phase of our strategy, building out a pipeline of differentiated and clinically meaningful, development-stage medicines to drive sustainable growth over the long term.  At the same time, we remain focused on commercial execution and optimizing the growth of our rare disease medicines, –as well as considering future commercial asset acquisitions. 

Rare Disease Medicines Are Driving Our Sales Growth

Net sales of our rare disease medicines grew 60 percent in 2017 compared to 2016.  Net sales of KRYSTEXXA for refractory chronic gout, PROCYSBIalone, our medicine for the treatment of uncontrolled gout, a rare genetic disease, nephropathic cystinosisgrew 72 percent in 2017, following the implementation of our commercial strategy to maximize the medicine’s growth trajectory following its acquisition in January of 2016.  We believe KRYSTEXXA has significant future growth potential and QUINSAIRinvested in its commercial organization in 2017, doubling its size to not only increase penetration in the rheumatology market, but also to tap into nephrology, a new market for chronic pulmonary infections associatedKRYSTEXXA.  We estimate that the nephrology market will have approximately the same addressable patient population as rheumatology.  Our orphan business unit, which includes RAVICTI, PROCYSBI and ACTIMMUNE, provides us with cystic fibrosis. a stable base of rare disease growth medicines. 

CAGR:  compound annual growth rate

Expanding Our Pipeline to Drive Sustainable Long-Term Growth

In May 2017, we acquired River Vision, and with the acquisition, added the first development-stage candidate to our pipeline – teprotumumab, a fully human monoclonal antibody (mAb) inhibitor of insulin-like growthfactor-1 receptor(IGF-1R). Teprotumumab, which demonstrated breakthrough efficacy in its Phase 2 trial, is in development for the treatment ofmoderate-to-severe TED, a rare and debilitating eye disease with no approved therapies.  Enrollment for the Phase 3 confirmatory trial began in October 2017.  We estimate the addressable population in the United States to be between 15,000 and 20,000 patients annually. 

We also delivered onexpanded our commitmentrheumatology pipeline programs in 2017, adding two next-generation biologic development programs to secure greater formulary accesssupport and sustain our leadership position in the treatment of uncontrolled gout, as well asHZN-002, a novel dexamethasone conjugate to augment our rheumatology portfolio.  In addition, two investigator-initiated immunomodulation studies are expected to start in 2018 to evaluate enhancing the response rate for our primary care medicines providing improved patient accessKRYSTEXXA. 

TRIPLE:  Tolerization Reduces Intolerance to Pegloticase and long-term durability for our clinically differentiated primary care medicines.Prolongs the Urate Lowering Effect.  RECIPE:  REduCing Immunogenicity to PegloticasE.  RIFLE:  RAYOS (delayed release prednisone) Inhibits Fatigue in Lupus Erythematosus.  OPTIC:  Treatment of Graves’ Orbitopathy (Thyroid Eye Disease) to Reduce Proptosis with Teprotumumab Infusions in a Randomized, Placebo-Controlled, Clinical Study.  CTCL:  cutaneousT-cell lymphoma.  HER2:  human epidermal growth factor receptor 2. 

Total Shareholder Return

While our talented team of employees executed well on our business strategy overOver the past year, 2016 was a challenging year for our sectorthree- and our share price, driven in part by uncertainty surrounding U.S. healthcare policy, which has continued into 2017. Ourone-year TSR in 2016 declined 25 percent, in line with our peer group as well as the NBI. However, a longer-term view on our TSR demonstrates thatfive-year periods, we have significantly outperformed both our peer group and the NBI overNasdaq Biotechnology Index (NBI).  With our durable base of rare disease medicines, our high-growth KRYSTEXXA medicine and the last three-pipeline we are building for future growth, we believe Horizon Pharma is well positioned for rapid and five-year periods.sustainable growth going forward. 

With a strategic focus on growing the business over the long term, it is imperative that our executive compensation program motivates our experienced, proven and talented management team in such a manner as to encourage – and reward – successful execution of thisthe Company’s long-term business strategy.

Our Pay Program

Our philosophy continues to be based on attracting and retaining top talent with experience in building and leading a successful biopharmaceutical company, while providing competitive compensation and benefits packages that create a direct, meaningful link between business results and compensation opportunities.  In thoughtfully doing so, we believe we can align interests of management, employees and shareholders to set priorities and focus on executing our long-term business strategy.

Say on Pay Results and Shareholder Engagement

We value the views of our shareholders, and have made meaningful engagement with our shareholders on compensation and governance issues a priority.  Feedback garnered during these outreach efforts informs the Compensation Committee’s thinking when evaluating our current compensation program and when considering potential modifications to the program on ago-forward basis.  For the past threefour years, led by the Chairman of our Compensation Committee, we have conducted continued and consistent engagement with our shareholders.

Last year at the 20162017 Annual General Meeting of Shareholders,oursay-on-pay proposal proposal received the support of approximately 6497 percent of the shares voted.  Our Board was disappointed inWe believe this outcome, and through shareholder engagement, we realized that several shareholders were not supportivehigh level of the front-loaded equity grant approach (where we granted three-year PSUs, tosupport is a result of our executive team) in 2015 and the reported value of those grants (although the realized value was, and is still effectively zero).

Since that meeting, our Compensation Committee and management have conducted a comprehensive shareholder outreach and engagement program to solicit feedback, understand investor concernsviewpoints and incorporate feedback into further discuss the mechanisms and rationale of the 2015 grants. We reached out to shareholders representing more than 40 percentdiscussions of our outstanding ordinary shares, as well as two of the leading proxy advisory firms, Institutional Shareholder Services, Inc.compensation programs and Glass Lewis & Co. These discussionsphilosophy. 

Through our shareholder engagement and outreach we have beenhad very productive conversations, which continue to shape our programs and informative, and have helped ensuredisclosures.  Recent changes that our Board’s ongoing decisions are aligned withwere heavily influenced by shareholder objectives.

During these discussions, our shareholders have generally been supportive of our business and growth strategy as well as our compensation philosophy. In addition, in response to the input we received from our shareholders during these conversations:feedback include:

Additionally, as we have previously committed, any of the PSUs that remain outstanding at the expiration of the three-year PSU performance period in 2018 but are not earned due to our failure to attain the requisite performance criteria will be cancelled at such time and the related ordinary shares will not be added back in the pool of shares available for grant under our equity plan.

Equity Grants in 2015

We have grown rapidly since our inception as a public company in 2011. Through organic growth and acquisitions, we grew from $7 million in sales in 2011 to more than $1 billion in 2016 and diversified our portfolio of medicines from two to 11. During this rapid growth, in late 2014, we realized that our executive officers had low ownership levels compared to other executive teams within our peer group – well below the 25^th percentile of the peer group. This meant that as we flourished and grew exponentially, our executives had not had the full opportunity to share in the value they were creating for shareholders. We felt this could impact the retention of our executives. Furthermore, it was important to ensure that management interests were fully aligned with those of shareholders, and management’s limited ownership was hindering that desired outcome.

As such, our Compensation Committee awarded equity grants in 2015 to our executives to bring ownership levels to market competitive levels and included time-based vesting equity in the form of options and restricted stock units (RSUs) with a vesting period of four years. The “X” in the graphic below shows share ownership levels for Mr. Walbert, Mr. Carey and Mr. Hoelscher, as compared to the peer group levelsafter we made these 2015 grants of time-based equity.

In addition, PSUs were granted in 2015, as well, which would only vest upon attainment of challenging TSR goals in order to further align executive and shareholder interests. The PSUs were split into three tranches with 3+ year performance periods and included atwo-year additional holding period for any awards that ultimately vested.

The equity grants awarded in 2015, both the time-based and performance-based grants, wereup-front grants intended to cover the next three years of equity grants for the executive team. The SEC’s disclosure rules require that the estimated value of all these grants be disclosed in the Summary Compensation Table in 2015 – even though they covered three years – and such reported value was driven by accounting and actuarial assumptions, rather than the actual value received as a result of theseup-front grants. As a result, total compensation realizable by the executive officers as a result of theseup-front grants based on the share price at December 31, 2016, was much less than that reported in the Summary Compensation Table for 2015. The Compensation Committee did not, has not and does not intend to award any other equity grants to these executive officers during this three-year PSU performance period, which ends in 2018. Additionally, as further described above, in response to shareholder feedback, when the PSU performance period ends in 2018, we will not again grant “front-loaded” awards that are intended to cover equity awards to the executive team for a multiple-year period.

In aggregate, these 2015 equity grants were made because the Compensation Committee felt confident this was a fair yet challenging equity pay package that would focus executives on our long-term success, increase executive share ownership and retain our top talent.

PSUs Align With Shareholder Value Creation

The PSUs are intended to provide economic incentives for our leadership team to create significant long-term shareholder value by tying the PSU vesting levels to attainment of aggressive TSR hurdles over a three-year performance period.

TSR during the performance period must be at least 15 percent compounded annually in order for any portion of the PSUs to vest. With a base price of $21.50 for the measurement, which is equal to the 20-trading-day volume weighted average trading price (20-day VWAP) ending on March 23, 2015, the date of grant, and a closing price of $16.18 on December 30, 2016, the PSUs had no realizable value as of December 31, 2016, as shown below. If the aggressive TSR hurdles are met, so that a portion of the PSUs vest, the increase in our shareholder return associated with that TSR will deliver a significant increase in our total shareholder value as shown in the following table:

Realizable Value of CEO Compensation

The table below shows compensation of our Chief Executive Officerchief executive officer (CEO), and compares the reported values in the Summary Compensation Table to the realizable value as of the end of fiscal year 20162017 based on our closing share price at that time.of $14.60 per share on December 29, 2017 (the last trading of the year).  As you can see,shown below, the grant date fair value of our CEO’s compensation packages – as required to be reported in the Summary Compensation Table – areis not at all reflective of the actual realizable value of the compensation package received by our CEO over the last three years.that could be received. 

Note:

“AggregatedAggregate Reported Value” includes compensation earned from 2014 to 20162017 as disclosed in the Summary Compensation Table annually.

“Aggregate Realizable Value” is defined as the compensation earned or deliverable for each year calculated as of the end of the 20162017 fiscal year, including:  actual salary received, actual amounts earned under the annual cash incentive plan, and the intrinsic value of long-term incentive plan components, as valued on 12/31/16December 31, 2017 usingtheyear-end share share price.  Options are valued based on spread value as of 12/31/16.December 31, 2017.  PSUs granted in 2015 are valued at zero based on fallingTSR being below threshold performance as of 12/31/16. The performance-based cash LTIP, granted in 2014, is similarly valued based on achieved performance as of 12/31/16.December 31, 2017. 

Compensation Program Governance

Our Compensation Committee is responsible for oversight of the Company’sour compensation program.  A significant part of this oversight is aligning management interests with our business strategies and goals, as well as the interests of our shareholders, while also mitigating excessive risk taking.  We continually take steps to strengthen and improve our executive compensation policies and practices.  Highlights of our current policies and practices include:

We believe in providing a competitive total compensation package to our executive management teamofficers through a combination of base salary, annual cash bonuses, long-term incentives and severance and change in controlchange-in-control benefits.  Our executive compensation programs are designed to achieve the following objectives:

Our Compensation Committee believes that our executive compensation programs should include short- and long-term performance incentive components, including cash and equity-based compensation, and should reward consistent performance that meets or exceeds expectations.  The Compensation Committee evaluates both performance and compensation to make sure that the total compensation provided to our executivesexecutive officers remains competitive relative to compensation paid by companies of similar size and stage of development, operating in the pharmaceutical industry and appropriately reflects our relative performance and our own strategic objectives.

Role of Compensation Committee

The Compensation Committee seeks to ensure that our executive compensation program is properly rewarding and motivating our executivesexecutive officers while aligning their goals with theour business strategy of Horizon Pharma and the interests of our shareholders.  To do this, our Compensation Committee conducts an annual review of the aggregate level of our executive compensation and the mix of elements used to compensate our executive officers and historic compensation levels, including prior equity award.awards. 

When setting executive compensation opportunities, the Compensation Committee considers several factors, including:

Role of Chief Executive Officer in Compensation Decisions

Our CEO typically evaluates the performance of other executive officers and other employees, along with the performance of the companyCompany as a whole, against previously determined objectives, on an annual basis and makes recommendations to the Compensation Committee with respect to annual base salary adjustments, bonuses, cash performance incentives and annual equity awards for the other executives.  The Compensation Committee exercises its own independent discretion in approving compensation for all executive officers.  The CEO is not present during deliberations or voting with respect to his own compensation.

Risk Analysis

The Compensation Committee has reviewed our compensation policies as generally applicable to our executive officers and other employees and believes that our policies do not encourage excessive and unnecessary risk-taking, and that the level of risk that they do encourage is not reasonably likely to have a material adverse effect on us.  The design of our compensation policies and programs encourages our executive officers and other employees to remain focused on both our short- and long-term goals.  For example, while our annualshort-term cash incentive plan measures performance on an annual basis, our equity LTIP awards, typicallywhich consist of time-based equity awards (RSUs) and performance-based equity awards (PSUs) vest over a number of years andyears.  Furthermore, a portion of our Cash LTIP and PSUs require that we achieve a specified level of TSRperformance over a three-year periodmulti-year periods, which we believe encourages our employees to focus on sustained potential shareholder return appreciation,execution of our long-term strategy, thus limiting the potential value of excessive risk-taking.

Role of Independent Consultant

The Compensation Committee retains the services of third-party, independent executive compensation consultants from time to time, as it sees fit, in connection with the establishment of compensation programs and related policies.  From January through September 2016, our Compensation Committee engaged Clearbridge as its independent compensation consultant. However, inSince October 2016, the Compensation Committee madehas engaged Radford, an Aon Hewitt Company and a change, choosing to engage Radfordsubsidiary of Aon plc (Radford), as its independent consultant.  Total fees paid to Clearbridge and Radford in 20162017 were approximately $185,000 and $129,000, respectively.$367,000.  Radford was engaged to assist and advise on all aspects of compensation program design and pay setting, including, but not limited to, the following services:

The Compensation Committee has assessed the independence of Radford according to the six factors mandated by SEC and NASDAQNasdaq Listing Rules.  After conducting this assessment and considering any potential conflicts of interest, the Compensation Committee concluded that the continued engagement of Radford did not raise any conflict of interest and did not adversely affect Radford’s independence.

Peer Group

Although our Compensation Committee has historically used the Radford survey data as a tool in determining executive compensation, it typically has not used a formula or “benchmark” to set our executives’ compensation in relation to this data.

Instead, the Compensation Committee generally references the 50^th percentile of comparable peer companies in combination with multiple other factors, such as the executives’ respective levels of experience and responsibility in determining the total target cash compensation for all executives.

Because we had recentlyIn May 2017, our Compensation Committee reviewed and updated our peer group in August 2015 as a result of our significant growth in connection with our merger transaction with Vidara (Vidara Merger) and for purposes of determiningmaking future compensation decisions.  The selection criteria used were headcount, revenue and market capitalization of companies in the August 2015 base salary increases, our Compensation Committee determined that this August 2015biotechnology and pharmaceutical industry.  Medivation and Actelion were removed from the peer group, continuedas both companies either had been or were in process of being acquired.  Acorda Therapeutics, Nektar Therapeutics and The Medicines Company were added to be appropriate in setting the 2016 executive compensation levels. As of December 31, 2015, thesepeer group.  These peer group companies had a2016 median EBITDAnet sales of $299approximately $746 million, as compared to our EBITDA of $106 million, median revenuesnet sales of approximately $860$981 million, as compared to our revenues of approximately $757 million and at the time the new peer group was adopted,30-day average median market capitalization of approximately $7.8$4.6 billion, as compared to our 30-day average market capitalization of approximately $2.6 billion.$2.4 billion, and median headcount at December 31, 2016 of 890 employees, as compared to our headcount of 1,050 employees. 

Our executive compensation program primarily consists of base salary, annual cash incentives and long-term incentives delivered through our equity awards and Cash LTIP.cash awards.  Employees in more senior roles have an increasing proportion of their total pay package at risk and tied to performance because they are in a position to have greater influence on the Company’sour performance results.

Base Salary

Base salaries for our executivesexecutive officers are established based on the individual’s scope of responsibilities, experience and market factors.  Base salaries are generally reviewed annually, typically in connection with our annual executive compensation review process.  The Compensation Committee also references survey and peer group data to understand the 50^th percentile of base salary compensation provided tomarketplace for individuals in similar positions at the peer group companies.

2016The annual base salaries forof our named executive officers wereNEOs as of March 1, 2017 and any increase from their prior base salary levels, if applicable, are as follows:

goals related solely to commercial-stage assets and were included as quantitative goals.  In 2017, the Company expanded the business development focus to include development-stage assets.  Given the complexity of quantifying business-development goals for development-stage assets, the Compensation Committee decided to establish qualitative business-development goals for 2017 instead of quantitative, as they had been set in prior years and therefore increasing the weighting of the 2017 qualitative goals to reflect this change. 

Quantitative Goals

The Compensation Committee originally established the quantitative goals for the 2017 plan year in November 2015 determinedFebruary 2017, with the goals allocated between net sales and adjusted earnings before interest, tax, depreciation and amortization (EBITDA) performance targets for the full 2017 calendar year.  However, two unanticipated developments occurred during 2017 after the Compensation Committee originally established these performance goals and targets. 

The first unanticipated development resulted from new business arrangements with pharmacy benefit managers (PBMs) and other payers that with respectwe had entered into in an effort to secure formulary status and reimbursement of our primary care medicines.  The resulting impact of the new arrangements differed significantly from expectations; specifically, we saw higher-than-expectedco-pay and other patient assistance costs as a percentage of gross sales and a higher-than-expected mix of PBM healthcare plans for which we pay higher commercial rebates.  In addition, we experienced a higher rate of managed care control in ournon-contracted business, an industry-wide trend, which ultimately resulted in significantly lower net pricing for our primary care medicines during 2017 when compared to the prior year while prescription performance was generally in line with our expectations. 

The second unanticipated development was the sale in late June of 2017 of our European subsidiary that owned the marketing rights to our medicines PROCYSBI^® and QUINSAIR™ for Europe, the Middle East and Africa (EMEA).  While the sale of the business generated significant value, it also resulted in a decrease of our full-year 2017 total net sales. 

Based on these unanticipated developments, it was apparent in the second quarter that the 2017 quantitative objectives,annual-goal threshold performance levels based on total net sales and adjusted EDITDA for 2017 were no longer attainable.  The Compensation Committee was concerned that the failure to have achievable performance goals under the annual incentive plan for executive officers and broad-based employees could further jeopardize our full-year results and believed it was important to provide motivation to deliver strong second-half 2017 results.  Therefore, the Compensation Committee approved modifications to each quantitative measure in August 2017, as described below.  Adjusting the quantitative goals allowed executive officers and other employees to refocus on net sales and adjusted EBITDA goals to drive performance for the second half of the year.  Each original goal, and its subsequent revision, is discussed in more detail below. 

Net Sales

The Compensation Committee adjusted the quantitative net sales metric to reference individual net sales goals for each of our three business units instead of total Company net sales.  Bysub-categorizing the performance goals by individual business unit, the performance of one business unit would not impact the achievement levels of the other business units.  In addition, to reflect the divestiture of the EMEA marketing rights to PROCYSBI and QUINSAIR, the net sales target for 2016 would be as follows, set at achievable yet appropriately challenging levels.the orphan business unit was reduced by the projected amount of net sales for the marketing rights sold.  The following tables compare the original net sales metrics to the revised net sales metrics:

Original Metric