REGENERON PHARMACEUTICALS, INC.

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

1. Interim Financial Statements

Basis of Presentation

The interim Condensed Consolidated Financial Statements of Regeneron Pharmaceuticals, Inc. and its subsidiaries ("Regeneron," "Company," "we," "us," and "our") have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company's financial position, results of operations, and cash flows in conformity with accounting principles generally accepted in the United States of America. In the opinion of management, these financial statements reflect all normal recurring adjustments and accruals necessary for a fair statement of the Company's condensed consolidated financial statements for such periods. The results of operations for any interim period are not necessarily indicative of the results for the full year. The December 31, 2025 Condensed Consolidated Balance Sheet data were derived from audited financial statements, but do not include all disclosures required by accounting principles generally accepted in the United States of America. These financial statements should be read in conjunction with the financial statements and notes thereto contained in the Company's Annual Report on Form 10-K for the year ended December 31, 2025.

Recently Issued Accounting Standards

2. Product Sales

Net product sales consist of the following:

As of September 30, 2026 and December 31, 2025, the Company had $4.132 billion and $3.458 billion, respectively, of trade accounts receivable that were recorded within Accounts receivable, net.

The Company had product sales to certain customers that each accounted for more than 10% of total gross product revenue for the three and nine months ended September 30, 2026 and 2025. Sales to each of these customers as a percentage of the Company's total gross product revenue are as follows:

3. Collaboration, License, and Other Agreements

a. Sanofi

The Company is party to a global collaboration with Sanofi to research, develop, and commercialize fully human monoclonal antibodies, which, as of September 30, 2026, consisted of Dupixent® (dupilumab), Kevzara® (sarilumab), and itepekimab.

In October 2026, the parties amended the collaboration agreement to include four additional long-acting, Regeneron-invented antibodies (the "New Licensed Products"). Under the terms of the amendment, the Company received an up-front payment of $1.0 billion from Sanofi (which will be recorded to Collaboration revenue in the fourth quarter of 2026), and the Company is entitled to receive up to an additional $7.0 billion in the aggregate upon the achievement of certain development, regulatory, and sales-based milestones. In addition, the Company will have the option, on an asset-by-asset basis after the completion of certain ongoing clinical trials, to include additional Sanofi-developed product candidates in the collaboration. In the event the Company exercises its option for any such product, the Company will reimburse Sanofi for certain development costs related to such product.

Agreed-upon development expenses incurred by the Company and Sanofi are shared equally. Sanofi leads commercialization activities for products under the collaboration agreement, and the Company has the right to co-commercialize such products on a country-by-country basis. The Company co-commercializes Dupixent in the United States and in certain countries outside the United States. The Company also supplies certain commercial bulk product to Sanofi. For Dupixent and Kevzara, the parties equally share profits from sales within the United States, and share profits outside the United States on a sliding scale based on sales starting at 65% (Sanofi)/35% (Regeneron) and ending at 55% (Sanofi)/45% (Regeneron). Global profits from sales of New Licensed Products will be shared equally between the parties.

Amounts recognized in the Company's Statements of Operations in connection with its Sanofi collaboration are as follows:

As of June 30, 2026, the "development balance," which represented the Company's obligation to reimburse Sanofi for development expenses that were previously funded by Sanofi, was fully repaid.

The following table summarizes contract balances in connection with the Company's Sanofi collaboration:

b. Bayer

The Company is party to a license and collaboration agreement with Bayer for the development and commercialization of EYLEA 8 mg (aflibercept 8 mg) and EYLEA (aflibercept). Agreed-upon development expenses incurred by the Company and Bayer are generally shared equally. The Company also supplies commercial bulk product to Bayer.

Bayer is responsible for commercialization activities outside the United States, and the companies share equally in profits from such sales. Within the United States, the Company is responsible for commercialization and retains profits from such sales.

Amounts recognized in the Company's Statements of Operations in connection with its Bayer collaboration are as follows:

The following table summarizes contract balances in connection with the Company's Bayer collaboration:

c. Other

In addition to the collaboration and license agreements discussed above, the Company has collaboration and license agreements that are not individually significant to its operating results or financial condition at this time. Pursuant to the terms of those agreements, the Company may (i) incur, and/or get reimbursed for, research and development expenses, and/or (ii) be required to pay, and/or may receive, additional amounts contingent upon the occurrence of various future events (e.g., upon the achievement of development and commercial milestones), which in the aggregate could be significant.

Acquired In-Process Research and Development ("IPR&D") Expenses

Acquired IPR&D expenses for the nine months ended September 30, 2026 included the premium on equity securities purchased and up-front, opt-in, and development milestone payments in connection with various collaboration and licensing agreements.

Acquired IPR&D expenses for the nine months ended September 30, 2025 included an $80.0 million up-front payment in connection with the Company's license agreement with Hansoh Pharmaceuticals Group Company Limited.

4. Net Income Per Share

The calculations of basic and diluted net income per share are as follows:

Shares which have been excluded from diluted per share amounts because their effect would have been antidilutive include the following:

5. Marketable Securities

Marketable securities as of September 30, 2026 and December 31, 2025 consist of both available-for-sale debt securities of investment grade issuers (see below and Note 6) as well as equity securities of publicly traded companies (see Note 6).

The following tables summarize the Company's investments in available-for-sale debt securities:

The Company classifies its investments in available-for-sale debt securities based on their contractual maturity dates. The available-for-sale debt securities as of September 30, 2026 mature at various dates through December 2032. The fair values of available-for-sale debt securities by contractual maturity consist of the following:

6. Fair Value Measurements

The following fair value hierarchy is used to classify assets and liabilities, based on inputs to valuation techniques utilized to measure fair value:

•Level 1 - Quoted prices in active markets for identical assets or liabilities

•Level 2 - Significant other observable inputs, such as quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-based valuations in which significant inputs used are observable

•Level 3 - Significant other unobservable inputs

The following tables summarize the Company's assets that are measured at fair value on a recurring basis:

In addition to the investments summarized in the table above, the Company recorded the following investments within Other noncurrent assets:

•As of September 30, 2026 and December 31, 2025, $607.6 million and $334.0 million, respectively, of equity securities that do not have a readily determinable fair value. The change in carrying value of such investments was primarily the result of additional purchases.

•As of September 30, 2026 and December 31, 2025, equity and other securities held through ownership interest in an investment fund of $207.0 million and $147.5 million, respectively, which are primarily measured at fair value based on Level 3 inputs. The change in carrying value was primarily the result of additional purchases by the fund.

Amounts recognized in Other income (expense), net, related to the Company's investments in equity securities consist of the following:

Other Fair Value Disclosures

The fair value of the Company's long-term debt, which was determined based on Level 2 inputs, was estimated to be $1.494 billion and $1.576 billion as of September 30, 2026 and December 31, 2025, respectively. The carrying value was $1.987 billion as of September 30, 2026 and $1.986 billion as of December 31, 2025.

7. Inventories

Inventories consist of the following:

Deferred costs represent the costs of product manufactured and shipped to the Company's collaborators for which recognition of revenue has been deferred.

8. Income Taxes

The Company's effective tax rate was 14.7% and 17.2% for the three months ended September 30, 2026 and 2025, respectively, and 14.4% and 12.6% for the nine months ended September 30, 2026 and 2025, respectively.

The Company's effective tax rate for the three and nine months ended September 30, 2026 and 2025 was positively impacted, compared to the U.S. federal statutory rate, primarily by income earned in foreign jurisdictions with tax rates lower than the U.S. federal statutory rate and, to a lesser extent, tax benefits from cross-border tax laws and federal tax credits for research activities, partly offset by changes in unrecognized tax benefits (which, for the nine months ended September 30, 2025, included the release of liabilities upon the settlement of an IRS audit). In addition, the Company's effective tax rate for the three and nine months ended September 30, 2025 was negatively impacted by the enactment of the "One Big Beautiful Bill Act," including the re-measurement of the Company's U.S. net deferred tax assets.

9. Stockholders' Equity

a. Share Repurchase Programs

The Company's board of directors has authorized share repurchase programs, including a share repurchase program for up to $3.0 billion of the Company's Common Stock which was authorized in April 2026. The programs have no time limit and can be discontinued at any time.

The table below summarizes the shares of the Company's Common Stock that the Company repurchased under its share repurchase programs and the cost of such shares, which were recorded as Treasury Stock.

As of September 30, 2026, $2.157 billion remained available for share repurchases under the Company's share repurchase program.

b. Dividends

In each of the first, second, and third quarters of 2026, the Company declared a quarterly cash dividend of $0.94 per share on its Common Stock and Class A Stock. Each quarterly dividend was paid to the Company's shareholders in the quarter in which the dividend was declared.

Additionally, in October 2026, the Company declared a cash dividend of $0.94 per share on its Common Stock and Class A Stock. The dividend will be payable to the Company's shareholders in December 2026.

10. Statement of Cash Flows

The following provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Condensed Consolidated Balance Sheets to the total of the same such amounts shown in the Condensed Consolidated Statements of Cash Flows:

Restricted cash consists of amounts held pursuant to contractual arrangements and for dividends payable on certain equity awards.

Supplemental disclosure of non-cash investing and financing activities

11. Segment Information

The Company operates inone business segment, which includes all activities related to the discovery, development, and commercialization of medicines for serious diseases. The determination of a single business segment is consistent with the consolidated financial information regularly provided to the Company's chief operating decision maker ("CODM"). The Company's CODM is its Chief Executive Officer, who reviews and evaluates consolidated net income for purposes of assessing performance, making operating decisions, allocating resources, and planning and forecasting for future periods.

In addition to the significant expense categories included within consolidated net income presented on the Company's Condensed Consolidated Statements of Operations, see below for disaggregated amounts that comprise research and development expenses:

12. Legal Matters

The Company is a party to legal proceedings that arise in the ordinary course of its business. The outcome of any such proceedings, regardless of the merits, is inherently uncertain. If the Company is unable to prevail in one or more of such proceedings, its consolidated financial position, results of operations, and future cash flows may be materially adversely impacted.

The Company recognizes gain contingencies associated with such proceedings when the award or recovery is realized or realizable and loss contingencies when it is probable that a liability will be incurred and the amount of loss can be reasonably estimated. As of September 30, 2026 and December 31, 2025, the Company's accruals for loss contingencies were not material. There are certain loss contingencies that the Company deems reasonably possible for which the possible loss or range of possible loss is not estimable at this time. Costs associated with the Company's involvement in legal proceedings are expensed as incurred.

a. Proceedings Relating to EYLEA (aflibercept) Injection

(1)United States

In addition to the patent infringement proceedings in the United States alleging infringement of certain Company patents pertaining to EYLEA discussed below, certain of these patents have also been subject to post-grant proceedings before the United States Patent and Trademark Office (the "USPTO").

On January 10, 2024, the Company filed a patent infringement lawsuit (as amended on January 7, 2026) against Amgen Inc. ("Amgen") in the United States District Court for the Central District of California (subsequently transferred to the United States District Court for the Northern District of West Virginia) alleging that Amgen's filing for U.S. Food and Drug Administration ("FDA") approval of an aflibercept 2 mg biosimilar infringed certain Company patents (as amended, the "2024 lawsuit"). On September 23, 2024, the court denied the Company's motion for a preliminary injunction, which decision was affirmed by the Federal Circuit on March 14, 2025. On June 17, 2025, the Company filed an additional patent infringement lawsuit against Amgen in the United States District Court for the Central District of California (subsequently transferred to the United States District Court for the Northern District of West Virginia) alleging that Amgen's continued commercialization of its aflibercept 2 mg biosimilar infringes the Company's U.S. Patent No. 12,331,099 (the "2025 lawsuit"). On September 12, 2025, Amgen filed its answer and counterclaims in the 2025 lawsuit alleging, among other things, that the Company obtained numerous patents fraudulently, rendering them unenforceable, and that obtaining and enforcing certain Company patents violated Section 2 of the Sherman Antitrust Act of 1890, as amended (the "Sherman Antitrust Act"). On March 9, 2026, Amgen filed its answer and counterclaims in the 2024 lawsuit; and, on April 20, 2026, the Company filed a motion to dismiss certain of Amgen's affirmative defenses and counterclaims in the 2024 lawsuit. On July 7, 2026, the court granted the Company's motion to dismiss Amgen's affirmative defenses and counterclaims challenged in the 2025 lawsuit with the exception of Amgen's prosecution delay affirmative defense and counterclaim. A claim construction hearing has been scheduled for December 1, 2026.

(2)Outside the United States

As described in greater detail below, the Company has filed patent infringement lawsuits against various parties in several jurisdictions outside the United States alleging infringement of certain Company patents pertaining to EYLEA, and certain of these patents have also been subject to post-grant proceedings before the European Patent Office (the "EPO") and/or other comparable foreign authorities.

(i) Multijurisdictional Settlements

Sam Chun Dang. On August 12, 2026, the Company and Bayer Consumer Care AG ("Bayer") entered into a settlement agreement with Sam Chun Dang Pharm. Co., Ltd ("Sam Chun Dang") in respect of Europe, South Korea, and certain other markets in the Asia-Pacific region. Pursuant to the settlement agreement, all pending judicial and administrative proceedings related to Sam Chun Dang's aflibercept 2 mg biosimilar product have been dismissed.

Sandoz. On October 9, 2026, the Company and Bayer entered into a settlement agreement with Sandoz AG and its affiliated entities (collectively, "Sandoz") in respect of all jurisdictions other than the United States, Australia, and Canada (each of which was separately settled in 2025, as previously disclosed). Pursuant to the settlement agreement, all remaining pending judicial and administrative proceedings related to Sandoz's aflibercept 2 mg biosimilar product, including the previously disclosed litigation in Germany, have been or will be dismissed.

(ii) Europe –EPO Post-Grant Proceedings

The Company's European Patent Nos. 2,944,306 (the "'306 Patent"), 3,716,992 (the "'992 Patent"), and 3,384,049 (the "'049 Patent") have been subject to post-grant proceedings before the Opposition Division ("OD") of the EPO:

•On November 26, 2024, following an oral hearing, the OD announced its decision to revoke the '306 Patent, which decision has been appealed by Regeneron.

•On October 22, 2025, following an oral hearing, the OD upheld the validity of the '992 Patent's claims in amended form, which decision has been appealed by Amgen.

•On April 21, 2026, following an oral hearing, the OD invalidated the '049 Patent. The Company did not appeal the OD's decision and, as a result, the '049 Patent has been revoked.

b. Proceedings Relating to EYLEA HD (aflibercept 8 mg) Injection

As described in greater detail below, certain of the Company's patents pertaining to EYLEA HD are subject to post-grant proceedings before the USPTO and the EPO as well as patent proceedings in certain jurisdictions outside the United States.

(1)United States –USPTO Post-Grant Proceedings

On September 18, 2025, Alvotech USA Inc. and Alvotech hf. (collectively, "Alvotech") petitioned the USPTO's Patent Trial and Appeal Board ("PTAB") for post-grant review ("PGR") of the Company's U.S. Patent No. 12,168,036 (the "'036 Patent"), alleging that such patent is invalid. On March 3, 2026, the PTAB instituted a PGR of the '036 Patent. Oral argument before the PTAB is scheduled for December 4, 2026.

(2)Outside the United States

(i) EPO Post-Grant Proceedings

Various parties, including Advanz Pharma Services UK Limited ("Advanz UK"), Alvotech hf., Amgen Inc., Intas Pharmaceuticals Ltd., Sandoz AG, and other, anonymous parties, are seeking revocation of the Company's European Patent Nos. 4,185,318 (the "'318 Patent") and 4,364,724 (the "'724 Patent") before the OD of the EPO.

(ii) Country-Specific Proceedings in Europe

In July and August 2026, Advanz Pharma Italia S.r.l. and Advanz UK (collectively, "Advanz") commenced actions against the Company and Bayer in Italy and the United Kingdom, respectively, seeking declarations that the Italian designations (in the Italian proceedings) and United Kingdom designations (in the U.K. proceedings) of the '318 Patent, the '724 Patent, and the Company's European Patent No. 3,790,532 are invalid as well as a declaration that Advanz's aflibercept 8 mg biosimilar does not infringe one or more of these patents.

c. Proceedings Relating to EYLEA (aflibercept) Injection Pre-filled Syringe

On July 17, 2020, the Company filed an antitrust lawsuit (as amended on January 25, 2021) against Novartis Pharma AG, Novartis Pharmaceuticals Corporation, and Novartis Technology LLC (collectively, "Novartis") and Vetter Pharma International GmbH in the United States District Court for the Southern District of New York (the "SDNY") seeking a judgment that the defendants' conduct relating to Novartis's attempt to assert its U.S. Patent No. 9,220,631 against Regeneron in 2020 violated Sections 1 and 2 of the Sherman Antitrust Act, and constituted tortious interference with contract. The Company is also seeking injunctive relief and treble damages. On September 21, 2021, this lawsuit was transferred to the Northern District of New York. On June 10, 2022, the Company filed an appeal of the District Court's decision to dismiss the amended complaint with the U.S. Court of Appeals for the Second Circuit (the "Second Circuit"). On March 18, 2024, the Second Circuit reversed the District Court's decision to dismiss the amended complaint and remanded the lawsuit to the District Court for further proceedings consistent with the Second Circuit's opinion. On November 19, 2024, the Company moved to transfer the lawsuit back to the SDNY, which motion was granted on December 5, 2024.

d. Proceedings Relating to Praluent (alirocumab) Injection

On May 27, 2022, the Company filed a lawsuit against Amgen in the United States District Court for the District of Delaware, alleging that, beginning in 2020, Amgen engaged in an anticompetitive bundling scheme which was designed to exclude Praluent from the market in violation of federal and state laws. The lawsuit seeks damages for harm caused by the alleged scheme, as well as injunctive relief restraining Amgen from continuing its alleged anticompetitive conduct. A trial was held in May 2025. On May 15, 2025, the jury reached a verdict in Regeneron's favor onnine of theten counts submitted to it and awarded Regeneron $135.6 million in compensatory damages and $271.2 million in punitive damages. On June 20, 2025, Amgen filed a post-trial motion for judgment as a matter of law or, in the alternative, for a new trial. Also on June 20, 2025, the Company filed a post-trial motion for (i) permanent injunctive relief, (ii) a constructive trust, and (iii) prejudgment interest. An oral hearing on Amgen's and Regeneron's respective post-trial motions was held on August 27, 2025.

e. Department of Justice Matters

On June 24, 2020, the U.S. Attorney's Office for the District of Massachusetts filed a civil complaint in the U.S. District Court for the District of Massachusetts alleging violations of the federal Anti-Kickback Statute and asserting causes of action under the federal False Claims Act and state law (the "June 2020 Civil Complaint") relating to the Company's support of 501(c)(3) organizations that provide financial assistance to patients. On September 27, 2023, the court (i) denied in part and granted in part the Company's motion for summary judgment and (ii) denied in its entirety the motion for partial summary judgment filed by the U.S. Attorney's Office for the District of Massachusetts. On October 25, 2023, the court certified for interlocutory appeal a portion of the court's September 27, 2023 order that addressed the causation standard applicable to the alleged violations of the federal Anti-Kickback Statute and federal False Claims Act. On February 18, 2025, the U.S. Court of Appeals for the First Circuit affirmed the portion of the court's September 27, 2023 order that had been certified for interlocutory appeal. On October 1, 2025, the U.S. Attorney's Office for the District of Massachusetts filed a second motion for partial summary judgment.

On June 3, 2021, the United States District Court for the Central District of California unsealed a qui tam complaint (as amended on October 29, 2021) filed against the Company, Regeneron Healthcare Solutions, Inc., and Sanofi-Aventis U.S. LLC by two qui tam plaintiffs (known as relators) purportedly on behalf of the United States and various states (the "State Plaintiffs"). The amended complaint alleges violations of the federal Anti-Kickback Statute and asserts causes of action under the federal False Claims Act and state law relating to allegedly unlawful remuneration and assistance provided to prescribers. Also on June 3, 2021, the United States and the State Plaintiffs notified the court of their decision to decline to intervene in the case. On January 14, 2022, the Company filed a motion to dismiss the amended complaint in its entirety. On July 25, 2023, the court granted in part and denied in part the Company's motion to dismiss. On September 1, 2023, the Company filed a second motion to dismiss the amended complaint or, in the alternative, a motion for judgment on the pleadings. On July 31, 2024 and August 15, 2024, respectively, the District Court granted the Company's second motion to dismiss the amended complaint with respect to the remaining causes of action under federal law and declined to exercise supplemental jurisdiction over the remaining causes of action under state law. On August 26, 2024, the qui tam plaintiffs filed a notice of appeal. Oral argument on the appeal was held on November 18, 2025. On August 19, 2026, the U.S. Court of Appeals for the Ninth Circuit (the "Ninth Circuit") reversed the District Court's decision to dismiss the amended complaint with respect to Regeneron in part, affirmed the decision in part, and remanded the lawsuit to the District Court for further proceedings.

In June 2021, the Company received a civil investigative demand ("CID") from the U.S. Department of Justice pursuant to the federal False Claims Act relating to, among other things, alleged inflated reimbursement rates for EYLEA by excluding applicable discounts, rebates, and benefits from the average sales price reported to the Centers for Medicare & Medicaid Services. On March 28, 2024, the U.S. District Court for the District of Massachusetts unsealed a qui tam complaint against the Company and others by two qui tam plaintiffs, purportedly on behalf of the United States and various states and municipalities, asserting causes of action under the federal False Claims Act and state and local laws, and alleging violations of the federal Anti-Kickback statute related to, among other things, the alleged conduct described above. Also on March 28, 2024, the U.S. Department of Justice and the U.S. Attorney's Office for the District of Massachusetts filed a civil complaint in partial intervention (the "March 2024 Civil Complaint") of the qui tam action, in the same court, asserting causes of action under the federal False Claims Act and a claim for unjust enrichment related to the alleged conduct described above. On June 25, 2024, the States of Colorado, Georgia, Michigan, North Carolina, Texas, and Washington filed a civil complaint in partial intervention (the "June 2024 Civil Complaint") in the same court asserting causes of action under various state laws related to the same alleged conduct. On April 29, 2025, the court denied the Company's motion to dismiss the March 2024 Civil Complaint and the June 2024 Civil Complaint. On June 18, 2025, the States of Maine, Nebraska, Ohio, Oregon, and Wyoming intervened in the action and filed a consolidated complaint asserting causes of action under their respective state laws.

On January 20, 2026, a qui tam plaintiff filed a complaint under seal against the Company and other pharmaceutical companies purportedly on behalf of the United States and various states. The complaint alleges violations of the federal Anti-Kickback Statute and other laws and asserts causes of action under the federal False Claims Act and various state laws relating to allegedly unlawful remuneration and assistance provided to prescribers. On May 22, 2026 and June 17, 2026, respectively, the United States and the applicable states notified the court of their decisions to decline to intervene in the case. On June 18, 2026, the United States District Court for the Central District of California unsealed the qui tam complaint. On July 20, 2026, the plaintiff filed an amended complaint. On August 19, 2026, the court dismissed the amended complaint; and, on September 9, 2026, the plaintiff filed a second amended complaint. On October 19, 2026, the court dismissed the action as to all defendants without prejudice for failure to timely serve the complaint and ordered the case closed.

f. Proceedings Initiated by Other Payors

The Company is party to several lawsuits relating to the conduct alleged in the June 2020 Civil Complaint discussed under "e. Department of Justice Matters" above. These lawsuits were filed by UnitedHealthcare Insurance Company and United Healthcare Services, Inc. (collectively, "UHC") and Humana Inc. ("Humana") in the SDNY on December 17, 2020 and July 22, 2021, respectively; and by Blue Cross and Blue Shield of Massachusetts, Inc. and Blue Cross and Blue Shield of Massachusetts HMO Blue, Inc. (collectively, "BCBS"), Medical Mutual of Ohio ("MMO"), Horizon Healthcare Services, Inc. d/b/a Horizon Blue Cross Blue Shield of New Jersey ("Horizon"), and Local 464A United Food and Commercial Workers Union Welfare Service Benefit Fund ("Local 464A") in the U.S. District Court for the District of Massachusetts on December 20, 2021, February 23, 2022, April 4, 2022, and June 17, 2022, respectively. These lawsuits allege causes of action under state law and the federal Racketeer Influenced and Corrupt Organizations Act ("RICO") and seek monetary damages and equitable relief. The MMO and Local 464A lawsuits are putative class action lawsuits. On December 29, 2021, the lawsuits filed by UHC and Humana were stayed by the SDNY pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts concerning the allegations in the June 2020 Civil Complaint. On September 27, 2022, the lawsuits filed by BCBS, MMO, and Horizon were stayed by the U.S. District Court for the District of Massachusetts pending resolution of the proceedings before the same court concerning the allegations in the June 2020 Civil Complaint; and, in light of these stays, the parties to the Local 464A action have also agreed to stay that matter.

On June 24, 2024, a group of plaintiffs purporting to be assignees of claims by various Medicare Advantage plans and related entities filed a putative class action complaint in the U.S. District Court for the District of Columbia on behalf of Medicare Advantage plans and other payors. The lawsuit relates to the conduct alleged in the June 2020 Civil Complaint, March 2024 Civil Complaint, and June 2024 Civil Complaint discussed under "e. Department of Justice Matters" above. The lawsuit alleges causes of action under state law and RICO and seeks monetary damages and equitable relief. On October 22, 2024, the Company filed a motion to transfer the proceedings to the U.S. District Court for the District of Massachusetts or, in the alternative, to stay the proceedings or dismiss the proceedings. On January 28, 2025, pursuant to a stipulation among the parties, the proceedings were transferred to the U.S. District Court for the District of Massachusetts. On February 1, 2025, the parties jointly filed a stipulation to stay the action pending resolution of the proceedings before the same court concerning the allegations in the June 2020 Civil Complaint.

g. Shareholder Derivative Complaint – Department of Justice June 2020 Civil Complaint Matters

On June 29, 2021, an alleged shareholder filed a shareholder derivative complaint in the Supreme Court of the State of New York (the "NY Supreme Court"), naming the then-current and certain former members of the Company's board of directors and certain then-current and former executive officers of the Company as defendants and Regeneron as a nominal defendant. The complaint asserts that the individual defendants breached their fiduciary duties in relation to the allegations in the June 2020 Civil Complaint discussed under "e. Department of Justice Matters" above. The complaint seeks an award of damages allegedly sustained by the Company; an order requiring Regeneron to take all necessary actions to reform and improve its corporate governance and internal procedures; disgorgement from the individual defendants of all profits and benefits obtained by them resulting from their sales of Regeneron stock; and costs and disbursements of the action, including attorneys' fees. On July 28, 2021, the defendants filed a notice of removal, removing the case from the NY Supreme Court to the SDNY. On September 23, 2021, the plaintiff moved to remand the case to the NY Supreme Court. Also on September 23, 2021, the individual defendants moved to dismiss the complaint in its entirety. On December 19, 2022, the SDNY denied the plaintiff's motion to remand the case and granted a motion to stay the case pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts concerning the allegations in the June 2020 Civil Complaint. As a result of the stay, the court also terminated the Company's motion to dismiss the complaint without prejudice. The Company can therefore renew the motion to dismiss upon conclusion of the stay.

h. Shareholder Derivative Complaints – Department of Justice March 2024 Civil Complaint Matters

In 2025, various purported shareholders of the Company filed several shareholder derivative complaints in the SDNY or the NY Supreme Court against members of the Company's board of directors and certain current and former executive officers of the Company as defendants and Regeneron as a nominal defendant. The complaints allege that the individual defendants, among other things, breached their fiduciary duties to the Company by failing to properly manage and oversee the Company in connection with the conduct alleged in the March 2024 Civil Complaint discussed under "e. Department of Justice Matters" above, and one lawsuit also alleges a breach of fiduciary duty relating to the conduct alleged in the January 2025 Class Action Complaint discussed under "k. Class Action Civil Complaints" below. The complaints also allege that the individual defendants breached the federal securities laws, wasted corporate assets, and unjustly enriched themselves at the expense of the Company. The complaints seek, among other things, an award of damages allegedly sustained by the Company as a result of the alleged misconduct of the individual defendants; an order requiring the individual defendants to take all necessary actions to reform and improve the Company's corporate governance and internal procedures; and costs and disbursements of the applicable action, including attorneys' fees. The cases filed in the SDNY were consolidated and stayed pending resolution of the motion to dismiss, including any appeal of the decision on the motion to dismiss, filed in the January 2025 Class Action Complaint discussed under "k. Class Action Civil Complaints" below. The shareholder derivative complaints filed in the NY Supreme Court were removed to the SDNY, and the purported shareholders filed motions to remand. On March 16, 2026, the SDNY denied the motions to remand and consolidated the cases with the other shareholder derivative lawsuits pending in the SDNY (which, as noted above, are subject to a stay).

i. Shareholder Derivative Complaint – July 2026 Securities Class Action

On September 23, 2026, an alleged shareholder filed a shareholder derivative complaint in the SDNY, naming members of the Company's board of directors and certain executive officers and employees of the Company as defendants and Regeneron as a nominal defendant. The complaint alleges, among other things, that the individual defendants violated securities laws, breached their fiduciary duties, and wasted corporate assets by failing to properly manage and oversee the Company in connection with the conduct alleged in the July 2026 Class Action Complaint discussed under "k. Class Action Civil Complaints" below.

j. Shareholder Derivative Complaint – Director Compensation

On July 22, 2025, an alleged shareholder filed a shareholder derivative complaint in the NY Supreme Court, naming the current non-employee members of the Company's board of directors, and the co-Chairs of the Company's board of directors (who also serve as Regeneron's President and Chief Executive Officer and Regeneron's President and Chief Scientific Officer, respectively) as defendants and Regeneron as a nominal defendant. The complaint asserts that the individual defendants breached their fiduciary duties and/or were unjustly enriched when they approved and/or received allegedly excessive non-employee director compensation in 2024 and 2025, and that this allegedly excessive compensation was a waste of corporate assets. The complaint seeks damages in favor of Regeneron for the alleged breaches of fiduciary duties, unjust enrichment, and waste of corporate assets; improvements to Regeneron's corporate governance and internal procedures; equitable relief, including restitution from the individual defendants; and award of the costs of the action, including attorneys' fees. An oral hearing on the Company's motion to dismiss the complaint was held on April 17, 2026. On June 22, 2026, plaintiff's counsel filed a motion to substitute the named plaintiff. On October 9, 2026, the court denied the Company's motion to dismiss as to the plaintiff's breach of fiduciary duty claim, but granted it as to the unjust enrichment and corporate waste claims. The court also granted the plaintiff's motion to substitute the named plaintiff.

k. Class Action Civil Complaints

On January 7, 2025 (as amended on September 8, 2025 and October 30, 2025), a purported shareholder filed a putative class action civil complaint (the "January 2025 Class Action Complaint"), on behalf of himself and all others similarly situated, in the SDNY against the Company and certain current and former executive officers of the Company. The second amended complaint asserts violations of federal securities laws in connection with statements or disclosures purportedly related to the conduct alleged in the March 2024 Civil Complaint discussed under "e. Department of Justice Matters" above as well as allegations relating to the launch of EYLEA HD. On July 10, 2025, the court appointed a lead plaintiff and lead counsel for the action. On November 17, 2025, the Company filed a motion to dismiss the second amended complaint. An oral hearing on the Company's motion to dismiss was held on June 25, 2026. On September 18, 2026, the court granted the Company's motion to dismiss; and, on October 15, 2026, the purported shareholder filed a notice of appeal.

On July 16, 2026, a purported shareholder filed a putative class action civil complaint (the "July 2026 Class Action Complaint"), on behalf of herself and all others similarly situated, in the SDNY against the Company and certain employees of the Company. The complaint asserts violations of federal securities laws in connection with statements or disclosures purportedly related to the Company's fianlimab clinical development program.

l. Sanofi Litigation

On November 18, 2024, the Company filed a lawsuit (as amended on December 20, 2024) in the SDNY against Sanofi and certain of its affiliated entities (collectively, "Sanofi"). The lawsuit alleged that the defendants breached certain provisions of the parties' Amended and Restated License and Collaboration Agreement, dated as of November 10, 2009 (as amended, the "Collaboration Agreement"), concerning Sanofi's obligation to provide Regeneron with full access to material information relating to the commercialization of Dupixent or other products commercialized pursuant to the Collaboration Agreement and Regeneron's audit rights under the Collaboration Agreement. The lawsuit sought a declaratory judgment, injunctive relief, damages, and other relief. On March 17, 2026, the court denied Sanofi's motion to dismiss the complaint. On October 1, 2026, the parties entered into a settlement agreement, pursuant to which this lawsuit has been dismissed.

m. Dupixent Product Liability Litigation

Since 2025, a number of product liability lawsuits have been filed in various U.S. district and state courts against the Company and certain of Sanofi's affiliated entities claiming that Dupixent either caused or exacerbated the patients' T-cell lymphoma, and asserting causes of action under various state laws. On February 13, 2026, several of the plaintiffs filed a motion with the United States Judicial Panel on Multidistrict Litigation (the "JPML") seeking to consolidate the federal lawsuits for coordinated pretrial proceedings. On June 4, 2026, the JPML issued an order transferring the federal lawsuits to the District of New Jersey for coordinated pretrial proceedings. On September 15, 2026, the parties filed a joint request seeking to consolidate the state lawsuits in New Jersey for coordinated pretrial proceedings.

On July 17, 2026, two plaintiffs filed a putative class action lawsuit in the United States District Court for the District of Maryland, alleging that the Company failed to warn that Dupixent allegedly causes or is linked to the development of cutaneous T-cell lymphoma. The complaint asserts causes of action under various state laws and seeks damages and equitable relief, including the creation of a fund to finance Dupixent medical monitoring and treatment services. On August 25, 2026, this action was transferred to the federal multidistrict litigation pending in the District of New Jersey.