Regeneron Reports Fourth Quarter and Full Year 2016 Financial and Operating Results Fourth quarter 2016 EYLEA (aflibercept) Injection U.S. net sales increased 15% to $858 million versus fourth quarter 2015

Regeneron Reports Fourth Quarter and Full Year 2016 Financial and Operating Results

Tarrytown, New York (February 9, 2017) -- Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced financial results for the fourth quarter and full year 2016 and provided a business update.

"The hard work of our scientists over the last decades has brought Regeneron to the next phase of our evolution - this year we anticipate launching two additional important therapies, significantly expanding our impact for patients with serious diseases and our company's growth potential," said Leonard S. Schleifer, M.D., Ph.D., President and Chief Executive Officer of Regeneron. "In March, we look forward to the potential U.S. approval of Dupixent, our innovative and breakthrough IL4/13 blocking antibody, in adults with atopic dermatitis. We believe Dupixent may have the potential to help additional patients with serious allergic diseases, with pivotal Phase 3 data in adult asthma patients expected later this year. We are also studying Dupixent in patients with nasal polyps and pediatric patients with asthma or atopic dermatitis."

Marketed Product Update

EYLEA (aflibercept) Injection for Intravitreal Injection

Praluent (alirocumab) Injection for the Treatment of Elevated Low-Density Lipoprotein (LDL) Cholesterol

Regeneron has sixteen product candidates in clinical development. These consist of EYLEA and fifteen fully human monoclonal antibody product candidates generated using the Company's VelocImmune technology, including six in collaboration with Sanofi. In addition to EYLEA and Praluent, highlights from the antibody pipeline include:

Sarilumab, the Company's antibody targeting IL-6R for rheumatoid arthritis.

Dupixent (dupilumab), the Company's antibody that blocks signaling of IL-4 and IL-13, is currently being studied in atopic dermatitis, asthma, nasal polyps, and eosinophilic esophagitis.

Sanofi's Le Trait Facility Update

REGN2810, the Company's antibody to programmed cell death protein 1 (PD-1), is being studied in patients with cancer. A Phase 2 potentially pivotal study for the treatment of advanced cutaneous squamous cell carcinoma, as well as various Phase 1 studies, continue to enroll patients.

Fasinumab, the Company's antibody targeting Nerve Growth Factor (NGF), is being studied in patients with pain due to osteoarthritis and chronic low back pain.

Nesvacumab, an antibody to Ang2 co-formulated with aflibercept for intravitreal injection, is currently being studied in patients with neovascular age-related macular degeneration (wet AMD) and diabetic macular edema (DME). The Phase 2 RUBY study of nesvacumab/aflibercept for the treatment of DME completed enrollment during the fourth quarter of 2016, and the Phase 2 ONYX study of nesvacumab/aflibercept for the treatment of wet AMD completed enrollment during the first quarter of 2017.

REGN3767, an antibody to Lymphocyte Activation Gene 3 (LAG-3) protein, entered Phase 1 clinical development for treatment of advanced malignancies in the fourth quarter of 2016.

REGN2477, an antibody to Activin A, received orphan drug designation from the FDA for the treatment of Fibrodysplasia Ossificans Progressiva (FOP) in the first quarter of 2017.

Select Upcoming 2017 Milestones

Fourth Quarter and Full Year 2016 Financial Results

Product Revenues: Net product sales were $863 million in the fourth quarter and $3.338 billion for the full year 2016, compared to $750 million in the fourth quarter and $2.689 billion for the full year 2015. EYLEA net product sales in the United States were $858 million in the fourth quarter and $3.323 billion for the full year 2016, compared to $746 million in the fourth quarter and $2.676 billion for the full year 2015.

Total Revenues: Total revenues, which include product revenues described above, increased by 12% to $1.227 billion in the fourth quarter of 2016, compared to $1.098 billion in the fourth quarter of 2015. Total revenues also include Sanofi and Bayer collaboration revenues of $313 million in the fourth quarter of 2016, compared to $330 million in the fourth quarter of 2015. Full year 2016 total revenues increased by 18% to $4.860 billion, compared to $4.104 billion for the full year 2015, and included collaboration revenues of $1.403 billion for the full year 2016, compared to $1.339 billion for the full year 2015. Refer to Table 4 for a summary of collaboration revenue.

Research and Development (R&D) Expenses: In 2016, GAAP R&D expenses were $479 million in the fourth quarter and $2.052 billion for the full year, compared to $461 million in the fourth quarter and $1.621 billion for the full year 2015. The higher R&D expenses for the full

year 2016 compared to the full year 2015 were principally due to the $75 million up-front payment made in connection with the April 2016 license and collaboration with Intellia, the $25 million up-front payment made in connection with the July 2016 license and collaboration agreement with Adicet, higher development costs, including manufacturing drug supplies, primarily related to fasinumab and REGN2810, and higher headcount to support the Company's increased R&D activities, partly offset by lower development costs primarily related to Praluent. In addition, in 2016, R&D-related non-cash share-based compensation expense was $75 million for the fourth quarter and $313 million for the full year, compared to $73 million in the fourth quarter and $256 million for the full year 2015.

Selling, General, and Administrative (SG&A) Expenses: In 2016, GAAP SG&A expenses were $326 million in the fourth quarter and $1.178 billion for the full year, compared to $295 million in the fourth quarter and $839 million for the full year 2015. The higher SG&A expenses for the full year 2016 compared to the full year 2015 were primarily due to higher commercialization-related expenses in connection with EYLEA and Praluent, higher commercialization-related expenses in connection with preparing to launch sarilumab and dupilumab, and higher headcount. In addition, in 2016, SG&A-related non-cash share-based compensation expense was $74 million for the fourth quarter and $231 million for the full year, compared to $82 million in the fourth quarter and $193 million for the full year 2015.

Cost of Goods Sold (COGS): In 2016, GAAP COGS was $45 million in the fourth quarter and $195 million for the full year, compared to $71 million in the fourth quarter and $242 million for the full year 2015. COGS decreased principally due to a decrease in royalties since the Company's obligation to pay Genentech based on U.S. sales of EYLEA ended in May 2016, partly offset by an increase in various start-up costs in connection with the Company's Limerick, Ireland commercial manufacturing facility and an increase in U.S. EYLEA net sales.

Cost of Collaboration and Contract Manufacturing (COCM): In 2016, GAAP COCM was $30 million in the fourth quarter and $105 million for the full year, compared to $40 million in the fourth quarter and $151 million for the full year 2015. COCM decreased primarily due to lower royalties since the Company's obligation to pay Genentech based on sales of EYLEA outside the United States also ended in May 2016.

Income Tax Expense: In the fourth quarter of 2016, GAAP income tax expense was $88 million and the effective tax rate was 25.9%, compared to $72 million and 31.8% in the fourth quarter of 2015. In 2016, GAAP income tax expense was $434 million and the effective tax rate was 32.7% for the full year, compared to $589 million and 48.1% for the full year 2015. The effective tax rates for the both the fourth quarter and full year of 2016 were positively impacted, compared to the U.S. federal statutory rate, primarily by the tax benefit associated with stock-based compensation, partly offset by the negative impact of losses incurred in foreign jurisdictions with rates lower than the federal statutory rate. As described in Table 3 of this press release, the Company adopted Accounting Standards Update 2016-09 (ASU 2016-09), Compensation - Stock Compensation, Improvements to Employee Share-Based Payment Accounting, during the second quarter of 2016. ASU 2016-09 requires companies to recognize all excess tax benefits and tax deficiencies in connection with stock-based compensation as income tax expense or benefit in the income statement (previously, excess tax benefits were recognized in additional paid-in capital on the balance sheet).

GAAP and Non-GAAP Net Income: The Company reported GAAP net income of $253 million, or $2.41 per basic share and $2.19 per diluted share, in the fourth quarter of 2016, compared to GAAP net income of $155 million, or $1.49 per basic share and $1.34 per diluted share, in the fourth quarter of 2015. The Company reported GAAP net income of $896 million, or $8.55 per basic share and $7.70 per diluted share, for the full year 2016, compared to GAAP net income of $636 million, or $6.17 per basic share and $5.52 per diluted share, for the full year 2015.

The Company reported non-GAAP net income of $353 million, or $3.35 per basic share and $3.04 per diluted share, in the fourth quarter of 2016, compared to non-GAAP net income of $258 million, or $2.48 per basic share and $2.23 per diluted share, in the fourth quarter of 2015. The Company reported non-GAAP net income of $1.319 billion, or $12.60 per basic share and $11.32 per diluted share, for the full year 2016, compared to non-GAAP net income of $944 million, or $9.16 per basic share and $8.12 per diluted share, for the full year 2015.

A reconciliation of the Company's GAAP to non-GAAP results is included in Table 3 of this press release.

Tarrytown, New York Facilities Update: On December 30, 2016, the Company entered into a Purchase Agreement with BMR-Landmark at Eastview LLC and BMR-Landmark at Eastview IV LLC (collectively, BMR), pursuant to which the Company has agreed to purchase from BMR its Tarrytown, New York facilities (the Facility), which includes laboratory and office space the Company's currently leases, for a purchase price of $720 million. The closing of the Purchase Agreement is anticipated in the first quarter of 2017.

The Company intends to fund the acquisition contemplated by the Purchase Agreement with a new financing; accordingly, the Company has entered into an engagement letter with Banc of America Leasing & Capital, LLC (BAL) to arrange a $720 million lease financing in connection with this acquisition. Immediately thereafter, the Company intends to lease the Facility from an affiliate of BAL for a term of five years. At the end of the lease term, the Company expects to have an option to extend the term of the lease, purchase the Facility at a predetermined amount, or sell the Facility to a third party on behalf of BAL.

2017 Financial Guidance(3)

The Company's full year 2017 financial guidance consists of the following components:

Conference Call Information

Regeneron will host a conference call and simultaneous webcast to discuss its fourth quarter and full year 2016 financial and operating results on Thursday, February 9, 2017, at 8:30 AM. To access this call, dial (888) 771-4371 (U.S.) or (847) 585-4405 (International). A link to the webcast may be accessed from the "Events and Presentations" page of Regeneron's website at www.regeneron.com. A replay of the conference call and webcast will be archived on the Company's website and will be available for 30 days.

About Regeneron Pharmaceuticals, Inc.

Regeneron is a leading science-based biopharmaceutical company that discovers, invents, develops, manufactures, and commercializes medicines for the treatment of serious medical conditions. Regeneron commercializes medicines for eye diseases, high LDL-cholesterol, and a rare inflammatory condition and has product candidates in development in other areas of high unmet medical need, including rheumatoid arthritis, atopic dermatitis, asthma, pain, cancer, and infectious diseases. For additional information about the Company, please visit www.regeneron.com or follow @Regeneron on Twitter.

Forward-Looking Statements and Use of Digital Media

This press release includes forward-looking statements that involve risks and uncertainties relating to future events and the future performance of Regeneron Pharmaceuticals, Inc. ("Regeneron" or the "Company"), and actual events or results may differ materially from these forward-looking statements. Words such as "anticipate," "expect," "intend," "plan," "believe," "seek," "estimate," variations of such words and similar expressions are intended to identify such forward-looking statements, although not all forward-looking statements contain these identifying words. These statements concern, and these risks and uncertainties include, among others, the nature, timing, and possible success and therapeutic applications of Regeneron's products, product candidates, and research and clinical programs now underway or planned; risks associated with intellectual property of other parties and pending or future litigation relating thereto, including without limitation the patent litigation relating to Praluent, the permanent injunction granted by the United States District Court for the District of Delaware that, if upheld on appeal, would prohibit Regeneron and Sanofi from marketing, selling, or manufacturing Praluent in the United States, the outcome of any appeals regarding such injunction, the ultimate outcome of such litigation, and the impact any of the foregoing may have on Regeneron's business, prospects, operating results, and financial condition; the likelihood and timing of achieving any of the anticipated milestones described in this news release; unforeseen safety issues resulting from the administration of products and product candidates in patients, including serious complications or side effects in connection with the use of Regeneron's product candidates in clinical trials; the likelihood and timing of possible regulatory approval and commercial launch of Regeneron's late-stage product candidates and new indications for marketed products, including without limitation EYLEA (aflibercept) Injection, Praluent (alirocumab) Injection, sarilumab, Dupixent (dupilumab), REGN2810, fasinumab, nesvacumab, REGN3767, and REGN2477; ongoing regulatory obligations and oversight impacting Regeneron's marketed products (such as EYLEA and Praluent), research and clinical programs, and business, including those relating to patient privacy; determinations by regulatory and administrative governmental authorities which may delay or restrict Regeneron's ability to continue to develop or commercialize Regeneron's products and product candidates; competing

drugs and product candidates that may be superior to Regeneron's products and product candidates; uncertainty of market acceptance and commercial success of Regeneron's products and product candidates and the impact of studies (whether conducted by Regeneron or others and whether mandated or voluntary), on the commercial success of Regeneron's products and product candidates; the ability of Regeneron to manufacture and manage supply chains for multiple products and product candidates, as well as actions by Regeneron's collaborators or third-party manufacturers, or other parties performing steps in the supply chain, impacting the foregoing; coverage and reimbursement determinations by third-party payers, including Medicare and Medicaid; unanticipated expenses; the costs of developing, producing, and selling products; the ability of Regeneron to meet any of its sales or other financial projections or guidance and changes to the assumptions underlying those projections or guidance, including without limitation those relating to EYLEA U.S. net product sales, Sanofi reimbursement of Regeneron commercialization-related expenses, non-GAAP unreimbursed R&D, non-GAAP SG&A, effective tax rate, and capital expenditures; and the potential for any license or collaboration agreement, including Regeneron's agreements with Sanofi, Bayer, and Teva Pharmaceutical Industries Ltd. (or their respective affiliated companies, as applicable), to be cancelled or terminated without any further product success. A more complete description of these and other material risks can be found in Regeneron's filings with the U.S. Securities and Exchange Commission. Any forward-looking statements are made based on management's current beliefs and judgment, and the reader is cautioned not to rely on any forward-looking statements made by Regeneron. Regeneron does not undertake any obligation to update publicly any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

Regeneron uses its media and investor relations website and social media outlets to publish important information about the Company, including information that may be deemed material to investors. Financial and other information about Regeneron is routinely posted and is accessible on Regeneron's media and investor relations website (http://newsroom.regeneron.com) and its Twitter feed (http://twitter.com/regeneron).

Non-GAAP Financial Measures

This press release and/or the financial results attached to this press release include amounts that are considered "non-GAAP financial measures" under SEC rules. As required, Regeneron has provided reconciliations of historical non-GAAP financial measures.

REGENERON PHARMACEUTICALS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited)

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RECONCILIATION OF GAAP NET INCOME TO NON-GAAP NET INCOME (Unaudited)

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