Legal Matters	12 Months Ended
Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Legal Matters	Legal MattersFrom time to time, the Company is a party to legal proceedings in the course of the Company's business. Costs associated with the Company's involvement in legal proceedings are expensed as incurred. The outcome of any such proceedings, regardless of the merits, is inherently uncertain. The Company recognizes accruals for loss contingencies associated with such proceedings when it is probable that a liability will be incurred and the amount of loss can be reasonably estimated. As of December 31, 2021 and 2020, the Company's accruals for loss contingencies were not material. If the Company were unable to prevail in any such proceedings, its consolidated financial position, results of operations, and future cash flows may be materially impacted. Proceedings Relating to Praluent (alirocumab) Injection As described in greater detail below, the Company is currently a party to patent infringement actions initiated by Amgen Inc. (and/or its affiliated entities) against the Company and/or Sanofi (and/or the Company's and Sanofi's respective affiliated entities) in a number of jurisdictions relating to Praluent. See Note 3 for a description of the Company's and Sanofi's arrangement regarding the costs resulting from or associated with such actions. United States In the United States, Amgen has asserted claims of U.S. Patent Nos. 8,829,165 (the "'165 Patent") and 8,859,741 (the "'741 Patent"), and sought a permanent injunction to prevent the Company and the Sanofi defendants from commercial manufacturing, using, offering to sell, or selling within the United States (as well as importing into the United States) (collectively, "Commercializing") Praluent. Amgen also seeks a judgment of patent infringement of the asserted patents, monetary damages (together with interest), costs and expenses of the lawsuits, and attorneys' fees. As described in greater detail under "Second Jury Trial and Appeal" below, on February 11, 2021, the Federal Circuit (as defined below) affirmed the lower court's decision that certain of Amgen's asserted patent claims are invalid based on lack of enablement. First Jury Trial and Appeal. The first jury trial in this litigation (the "First Trial") was held in the United States District Court for the District of Delaware (the "District Court") from March 8 to March 16, 2016. During the course of the First Trial, the District Court ruled as a matter of law in favor of Amgen that the asserted patent claims were not obvious, and in favor of the Company and the Sanofi defendants that there was no willful infringement of the asserted patent claims by the Company or the Sanofi defendants. On March 16, 2016, the jury returned a verdict in favor of Amgen in the First Trial, finding that the asserted claims of the '165 and '741 Patents were not invalid based on either a lack of written description or a lack of enablement. On October 5, 2017, the United States Court of Appeals for the Federal Circuit (the "Federal Circuit") reversed in part the District Court's decision and remanded for a new trial on the issues of written description and enablement. In addition, it affirmed the District Court's ruling that Amgen's patents were not obvious. Second Jury Trial and Appeal. On January 3, 2019, the District Court held oral argument in the remanded proceedings on the Company and the Sanofi defendants' motion for judgment on the pleadings regarding Amgen's willful infringement claim. On January 18, 2019, the District Court entered an order (i) denying the Company and the Sanofi defendants' motion for summary judgment on validity, (ii) denying Amgen's motion for partial summary judgment on estoppel, and (iii) granting the Company and the Sanofi defendants' cross-motion for summary judgment on estoppel. On February 8, 2019, the District Court granted the Company and the Sanofi defendants' motion for judgment on the pleadings, thereby dismissing Amgen's claim of willful infringement. The second jury trial in this litigation (the "Second Trial") was held before the District Court in February 2019 to determine the validity of Amgen's asserted patent claims. On February 25, 2019, the jury returned a verdict in the Second Trial generally in favor of Amgen, finding that two claims of the '165 Patent and one claim of the '741 Patent were not invalid. The jury also found that two claims of the '165 Patent were invalid for lack of adequate written description while rejecting the lack of enablement challenges to those two claims. On August 28, 2019, the District Court ruled as a matter of law that Amgen's asserted patent claims are invalid based on lack of enablement. The District Court also conditionally denied the Company and the Sanofi defendants' motion for a new trial. On October 23, 2019, Amgen filed a notice of appeal of the District Court's decision with the Federal Circuit. An oral hearing before the Federal Circuit was held on December 9, 2020. On February 11, 2021, the Federal Circuit affirmed the District Court's decision that certain of Amgen's asserted patent claims are invalid based on lack of enablement. On April 14, 2021, Amgen filed a petition for a rehearing en banc, which was denied on June 21, 2021. On November 18, 2021, Amgen filed a petition for writ of certiorari with the United States Supreme Court. Injunctive Relief Proceedings. On March 18, 2019, Amgen filed a renewed motion for a permanent injunction to prohibit the Company and the Sanofi defendants from Commercializing Praluent in the United States (a "Permanent Injunction"), and an oral hearing on this motion was held in June 2019. Previously, the Federal Circuit stayed and then vacated a Permanent Injunction granted by the District Court in connection with the First Trial. On August 28, 2019, the District Court dismissed as moot Amgen's renewed motion for a Permanent Injunction. Europe Amgen has asserted European Patent No. 2,215,124 (the "'124 Patent"), which pertains to PCSK9 monoclonal antibodies, in the countries in Europe discussed below. In October 2020, the '124 Patent claims directed to compositions of matter and medical use relevant to Praluent were ruled invalid based on a lack of inventive step by the Technical Board of Appeal (the "TBA") of the European Patent Office (the "EPO"). This decision impacted each of the infringement proceedings based on the '124 Patent discussed below. Amgen filed lawsuits in Germany, the United Kingdom, and France in July 2016, July 2016, and September 2016, respectively, against the Company and certain of Sanofi's affiliated entities for infringement of the relevant designation of the '124 Patent in each such jurisdiction; and these lawsuits were dismissed in November 2020, September 2021, and June 2021, respectively. The dismissal in Germany followed an earlier finding of infringement and granting of an injunction, both of which were subsequently overturned. In December 2019, Amgen also filed lawsuits in the Netherlands, Italy, and Spain for infringement of the relevant designation of the '124 Patent in each such jurisdiction; the Company was not named as a defendant in any of these actions, and each of these lawsuits was dismissed in February 2021. Japan As previously reported, on March 31, 2020, Amgen filed a lawsuit in the Tokyo District Court against Sanofi K.K. seeking damages incurred by Amgen as a result of the earlier finding of infringement of Amgen's Japanese Patent Nos. 5,906,333 and 5,705,288 by the Tokyo District Court Civil Division. The Company has not been named as a defendant in this damages action. Proceedings Relating to Dupixent (dupilumab) Injection United States On March 23, 2017, the Company, Sanofi-Aventis U.S. LLC, and Genzyme Corporation initiated an inter partes review ("IPR") in the United States Patent and Trademark Office ("USPTO") seeking a declaration of invalidity of U.S. Patent No. 8,679,487 (the "'487 Patent") owned by Immunex Corporation relating to antibodies that bind the human interleukin-4 receptor and subsequently filed two additional IPR petitions in the USPTO seeking declarations of invalidity of the '487 Patent based on different grounds (the "Additional IPR Petitions"). The Patent Trial and Appeal Board ("PTAB") of the USPTO issued a final written decision on the Additional IPR Petitions on February 14, 2019, invalidating all 17 claims of the '487 Patent as obvious. This decision was subsequently affirmed by the Federal Circuit and Immunex's petition for writ of certiorari was denied by the United States Supreme Court. The '487 Patent expired in May 2020 following Immunex's filing of a terminal disclaimer with the USPTO. On April 5, 2017, Immunex Corporation filed a lawsuit against the Company, Sanofi, Sanofi-Aventis U.S. LLC, Genzyme Corporation, and Aventisub LLC in the United States District Court for the Central District of California seeking a judgment of patent infringement of the '487 Patent and a declaratory judgment of infringement of the '487 Patent, in each case by the Company's and the other defendants' Commercializing of Dupixent; monetary damages (together with interest); an order of willful infringement of the '487 Patent, which would allow the court in its discretion to award damages up to three times the amount assessed; costs and expenses of the lawsuit; and attorneys' fees. The court subsequently granted a joint stipulation by the parties to stay the litigation pending resolution of the appeals of the PTAB's final written decisions on the Additional IPR Petitions discussed above; and, on August 3, 2021, granted a motion to dismiss the lawsuit, dismissing all of Immunex's claims with prejudice. Europe On September 30, 2016, Sanofi initiated a revocation proceeding in the United Kingdom to invalidate the U.K. counterpart of European Patent No. 2,292,665 (the "'665 Patent"), another patent owned by Immunex relating to antibodies that bind the human interleukin-4 receptor. At the joint request of the parties to the revocation proceeding, the U.K. Patents Court ordered on January 30, 2017 that the revocation action be stayed pending the final determination of the currently pending EPO opposition proceedings initiated by the Company and Sanofi in relation to the '665 Patent. The oral hearing before the EPO on the oppositions occurred on November 20, 2017, at which the claims of the '665 Patent were found invalid and the patent was revoked. A final written decision of revocation of the '665 Patent was issued by the EPO on January 4, 2018. Immunex filed a notice of appeal of the EPO's decision on January 31, 2018, and an oral hearing before the TBA has been scheduled for March 10–11, 2022. On September 20, 2017 and September 21, 2017, respectively, the Company and Sanofi initiated opposition proceedings in the EPO against Immunex's European Patent No. 2,990,420 (the "'420 Patent"), a divisional patent of the '665 Patent (i.e., a patent that shares the same priority date, disclosure, and patent term of the parent '665 Patent but contains claims to a different invention). The oral hearing before the EPO on the oppositions occurred on February 14–15, 2019, at which the '420 Patent was revoked in its entirety. Immunex filed a notice of appeal of the EPO's decision on May 31, 2019, and an oral hearing before the TBA has been scheduled for March 10–11, 2022. The original patent term of the Immunex patents expired in May 2021. Proceedings Relating to EYLEA (aflibercept) Injection On January 7, 2021, Chengdu Kanghong Pharmaceutical Group Co., Ltd. ("Chengdu Kanghong") filed an IPR petition in the USPTO against the Company' s U.S. Patent No. 10,464,992 (the "'992 Patent") and a post-grant review ("PGR") petition against the Company's U.S. Patent No. 10,828,345 (the "'345 Patent") seeking declarations of invalidity of the '992 Patent and '345 Patent. On June 23, 2021, Chengdu Kanghong filed motions to dismiss each of these petitions and terminate the respective proceedings, which were granted by the USPTO on June 25, 2021. On February 11, 2020, anonymous parties filed two requests for ex parte reexamination of the Company's U.S. Patent No. 10,406,226 and the '992 Patent, and the USPTO has granted both requests to initiate reexamination proceedings. On May 5, 2021, Mylan Pharmaceuticals Inc. filed IPR petitions in the USPTO against the Company's U.S. Patent Nos. 9,254,338 (the "'338 Patent") and 9,669,069 (the "'069 Patent") seeking declarations of invalidity of the '338 Patent and the '069 Patent. On November 10, 2021, the USPTO issued a decision instituting both IPR proceedings. On December 9, 2021, Apotex Inc. and Celltrion, Inc. each filed two separate IPR petitions against the Company's '338 and '069 Patents requesting that their IPRs be instituted and joined with the IPR proceedings initiated by Mylan concerning the '338 and '069 Patents. On September 7, 2021, Celltrion, Inc. filed a PGR petition in the USPTO against the Company's U.S. Patent No. 10,857,231 (the "'231 Patent") seeking a declaration of invalidity of the '231 Patent. On October 26 and October 27, 2021, anonymous parties initiated opposition proceedings in the EPO against the Company's European Patent No. 2,944,306 (the "'306 Patent") seeking revocation of the '306 Patent in its entirety. Proceedings Relating to EYLEA (aflibercept) Injection Pre-filled Syringe On June 19, 2020, Novartis Pharma AG, Novartis Pharmaceuticals Corporation, and Novartis Technology LLC (collectively, "Novartis") filed a complaint with the U.S. International Trade Commission (the "ITC") pursuant to Section 337 of the Tariff Act of 1930 requesting that the ITC institute an investigation relating to the importation into the United States and/or sale within the United States after importation of EYLEA pre-filled syringes ("PFS") and/or components thereof which allegedly infringe Novartis’s U.S. Patent No. 9,220,631 (the "'631 Patent"). Novartis also requested a permanent limited exclusion order forbidding entry into the United States of EYLEA PFS or components thereof; a permanent cease-and-desist order from the importation, sale, offer for sale, advertising, packaging, or solicitation of any sale by the Company of EYLEA PFS or components thereof; and a bond should the Company continue to import EYLEA PFS (if found to infringe) during, if applicable, any 60-day Presidential review period (i.e., the period when the President of the United States (or his designee) can disapprove any ITC decision to issue an exclusion order or cease-and-desist order). The ITC instituted the investigation on July 22, 2020 and a trial was scheduled for April 19–23, 2021. On March 26, 2021, the staff attorney appointed by the ITC's Office of Unfair Import Investigations ("OUII")—an independent government party to the case representing the public interest—determined that the '631 Patent is invalid on several grounds. On April 8, 2021, Novartis moved to terminate the ITC investigation in its entirety based on its withdrawal of the complaint; and, on May 3, 2021, the ITC terminated the investigation. On June 19, 2020, Novartis also filed a patent infringement lawsuit (as amended on August 2, 2021) in the U.S. District Court for the Northern District of New York asserting claims of the '631 Patent and seeking preliminary and permanent injunctions to prevent the Company from continuing to infringe the '631 Patent. Novartis also seeks a judgment of patent infringement of the '631 Patent, monetary damages (together with interest), an order of willful infringement of the '631 Patent (which would allow the court in its discretion to award damages up to three times the amount assessed), costs and expenses of the lawsuits, and attorneys' fees. On July 30, 2020, the court granted the Company's motion to stay these proceedings until a determination in the ITC proceedings discussed above, including any appeals therefrom, becomes final. On June 11, 2021, the court, at the request of Novartis, lifted the stay. On November 5, 2021, the Company filed a motion to stay these proceedings in light of the pending IPR proceeding discussed below. On January 31, 2022, the court denied the Company's motion to stay these proceedings. On July 16, 2020, the Company initiated two IPR petitions in the USPTO seeking a declaration of invalidity of the '631 Patent on two separate grounds. On January 15, 2021, the USPTO declined to institute an IPR proceeding on procedural grounds in light of the pending ITC investigation discussed above; the other IPR petition has been withdrawn. Following Novartis's motion to terminate the ITC investigation discussed above, on April 16, 2021 the Company filed a new IPR petition seeking a declaration of invalidity of the '631 Patent based on the same grounds that were the basis for the OUII staff attorney's determination discussed above. On October 26, 2021, the USPTO issued a decision instituting the IPR proceeding. On July 17, 2020, the Company filed an antitrust lawsuit against Novartis and Vetter Pharma International Gmbh ("Vetter") in the United States District Court for the Southern District of New York seeking a declaration that the '631 Patent is unenforceable and a judgment that the defendants' conduct violates Sections 1 and 2 of the Sherman Antitrust Act of 1890, as amended (the "Sherman Antitrust Act"). The Company is also seeking injunctive relief and treble damages. On September 4, 2020, Novartis filed, and Vetter moved to join, a motion to dismiss the complaint, to transfer the lawsuit to the Northern District of New York, or to stay the suit; and on October 19, 2020, Novartis filed, and Vetter moved to join, a second motion to dismiss the complaint on different grounds. On January 25, 2021, the Company filed an amended complaint seeking a judgment that Novartis's conduct violates Section 2 of the Sherman Antitrust Act based on additional grounds, as well as a judgment of tortious interference with contract. On February 22, 2021, Novartis filed, and Vetter moved to join, a motion to dismiss the amended complaint. On September 21, 2021, the court granted Novartis and Vetter's motion to transfer this lawsuit to the Northern District of New York. As a result, this lawsuit was transferred to the same judge that had been assigned to the patent infringement lawsuit discussed above. On November 5, 2021, the Company filed a motion to stay these proceedings in light of the pending IPR proceeding discussed above. On January 31, 2022, the court denied the Company's motion to stay these proceedings and granted Novartis and Vetter's motion to dismiss the amended complaint. Proceedings Related to "Most Favored Nation" Interim Final Rule On December 11, 2020, the Company filed a lawsuit in the United States District Court for the Southern District of New York against the U.S. Department of Health and Human Services, the Secretary of HHS, the Centers for Medicare & Medicaid Services ("CMS"), and the Administrator of CMS seeking declaratory and injunctive relief related to the interim final rule with comment period entitled "Most Favored Nation (MFN) Model" issued on November 20, 2020 by HHS, acting through CMS (the "MFN Rule"). On the same day, the Company filed a motion for a preliminary injunction and temporary restraining order, seeking to prevent implementation of the MFN Rule. On December 22, 2020, the court heard oral argument on the Company's motion for a preliminary injunction and temporary restraining order. On December 31, 2020, the court granted the Company's motion and issued a preliminary injunction. On February 2, 2021, the government stated to the court that the Solicitor General had determined not to appeal the preliminary injunction. On February 10, 2021, the court entered a 90-day stay of the litigation and subsequently extended the stay, with the most recent 60-day extension granted on January 4, 2022. On December 27, 2021, CMS published a final rule that rescinds the MFN Rule effective February 28, 2022. Proceedings Relating to fasinumab On May 21, 2020, the Company and Teva Pharmaceutical Industries Limited ("Teva") filed a lawsuit against Rinat Neurosciences Corp. ("Rinat"), a wholly owned subsidiary of Pfizer Inc., in the English High Court of Justice in London, seeking invalidation and revocation of Rinat's European Patent No. 2,270,048 (the "'048 Patent"), European Patent No. 1,871,416 (the "'416 Patent"), and European Patent No. 2,305,711 (the "'711 Patent"), each of which pertains to the use of NGF monoclonal antibodies to treat certain symptoms in patients suffering from osteoarthritis. On July 21, 2020, Rinat filed its defense and counterclaim seeking a declaration of infringement of the '048 Patent by fasinumab. The counterclaim also seeks a permanent injunction, damages, an accounting of profits, and costs and interest. On December 15, 2020, Rinat filed an amended defense and counterclaim seeking a declaration of infringement of the '711 Patent by fasinumab. On May 5, 2021, the court stayed this litigation on terms mutually agreed by the parties. The '048 Patent is subject to opposition proceedings in the EPO, which were initiated by the Company on August 10, 2016 and two other opponents on August 11, 2016. On January 3, 2018, the Opposition Division of the EPO issued a preliminary, non-binding opinion regarding the validity of the '048 Patent, indicating that it considered the granted patent to be invalid. An oral hearing on the oppositions against the '048 Patent was held on November 29–30, 2018, at which the Opposition Division upheld the validity of the '048 Patent's claims in amended form. The Company filed a notice of appeal to the TBA of the EPO on March 7, 2019. On October 21, 2020, Teva filed a notice of intervention with the TBA to take part in the appeal proceedings as an intervener. An oral hearing before the TBA has been scheduled for April 5–6, 2022. The '711 Patent is also subject to opposition proceedings in the EPO, which were initiated by the Company on May 1, 2018. On January 31, 2019, the Opposition Division of the EPO issued a preliminary, non-binding opinion regarding the validity of the '711 Patent, indicating that it considered the granted patent to be invalid. An oral hearing on the opposition against the '711 Patent was held on December 3, 2019, at which the Opposition Division upheld the validity of the '711 Patent's claims in amended form. The Company filed a notice of appeal to the TBA on December 20, 2019. On January 29, 2021, Teva filed a notice of intervention with the TBA to take part in the appeal proceedings as an intervener. An oral hearing before the TBA was held on July 29, 2021, at which the '711 Patent was revoked in its entirety. Proceedings Relating to REGEN-COV (casirivimab and imdevimab) On October 5, 2020, Allele Biotechnology and Pharmaceuticals, Inc. ("Allele") filed a lawsuit (as amended on April 8, 2021) against the Company in the United States District Court for the Southern District of New York, asserting infringement of U.S. Patent No. 10,221,221 (the "'221 Patent"). Allele seeks a judgment of patent infringement of the '221 Patent, an award of monetary damages (together with interest), an order of willful infringement of the '221 Patent (which would allow the court in its discretion to award damages up to three times the amount assessed), costs and expenses of the lawsuit, and attorneys' fees. On July 16, 2021, the Company filed a motion to dismiss the complaint. An oral hearing has been scheduled for March 2, 2022. Department of Justice Matters In January 2017, the Company received a subpoena from the U.S. Attorney's Office for the District of Massachusetts requesting documents relating to its support of 501(c)(3) organizations that provide financial assistance to patients; documents concerning its provision of financial assistance to patients with respect to products sold or developed by Regeneron (including EYLEA, Praluent, ARCALYST, and ZALTRAP®); and certain other related documents and communications. 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. On August 24, 2020, the Company filed a motion to dismiss the complaint in its entirety. On December 4, 2020, the court denied the motion to dismiss. In September 2019, the Company and Regeneron Healthcare Solutions, Inc., a wholly-owned subsidiary of the Company, each received a civil investigative demand ("CID") from the U.S. Department of Justice pursuant to the federal False Claims Act relating to remuneration paid to physicians in the form of consulting fees, advisory boards, speaker fees, and payment or reimbursement for travel and entertainment allegedly in violation of the federal Anti-Kickback Statute. The CIDs relate to EYLEA, Praluent, Dupixent, ZALTRAP, ARCALYST, and Kevzara and cover the period from January 2015 to the present. On June 3, 2021, the United States District Court for the Central District of California unsealed a qui tam complaint 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 the United States and various states (the "State Plaintiffs"), asserting causes of action under the federal False Claims Act and state law. 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 October 29, 2021, the qui tam plaintiffs filed an amended complaint in this matter. On January 14, 2022, the Company filed a motion to dismiss the amended complaint in its entirety. In June 2021, the Company received a CID from the U.S. Department of Justice pursuant to the federal False Claims Act. The CID states that the investigation concerns allegations that the Company (i) violated the False Claims Act by paying kickbacks to distributors and ophthalmology practices to induce purchase of EYLEA, including through discounts, rebates, credit card fees, free units of EYLEA, and inventory management systems; and (ii) inflated reimbursement rates for EYLEA by excluding applicable discounts, rebates, and benefits from the average sales price reported to CMS. The CID covers the period from January 2011 through June 2021. The Company is cooperating with this investigation. Proceedings Initiated by UnitedHealthcare On December 17, 2020, UnitedHealthcare Insurance Company and United Healthcare Services, Inc. (collectively, "UHC") filed a lawsuit against the Company in the United States District Court for the Southern District of New York alleging UHC has been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. UHC alleges causes of action under state law and the federal Racketeer Influenced and Corrupt Organizations Act (the "RICO Act") and seeks monetary damages and equitable relief. On March 1, 2021, the Company filed a motion to dismiss the complaint in its entirety. On March 25, 2021, UHC filed an amended complaint; and, on April 22, 2021, the Company filed a motion to dismiss this amended complaint in its entirety. On December 29, 2021, this lawsuit was stayed pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts discussed under "Department of Justice Matters" above. Proceedings Initiated by Humana On July 22, 2021, Humana Inc. ("Humana") filed a lawsuit against the Company in the United States District Court for the Southern District of New York alleging Humana has been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. Humana alleges causes of action under state law and the RICO Act and seeks monetary damages and equitable relief. On September 27, 2021, the Company filed a motion to dismiss the complaint in its entirety. On December 29, 2021, this lawsuit was stayed pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts discussed under "Department of Justice Matters" above. Proceedings Initiated by Blue Cross and Blue Shield On December 20, 2021, Blue Cross and Blue Shield of Massachusetts, Inc. and Blue Cross and Blue Shield of Massachusetts HMO Blue, Inc. (collectively, "BCBS") filed a lawsuit against the Company in the U.S. District Court for the District of Massachusetts alleging BCBS has been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. BCBS alleges causes of action under state law and the RICO Act and seeks monetary damages and equitable relief. Shareholder Demand On or about September 30, 2020, the Company's board of directors received a demand letter from a purported shareholder of the Company. The demand alleges that Regeneron and its shareholders have been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. The demand letter requests that the Company's board of directors investigate alleged breaches of fiduciary duty by its officers and directors and other alleged violations of law and corporate governance practices and procedures; bring legal action against the persons responsible for causing the alleged damages; and implement and maintain an effective system of internal controls, compliance mechanisms, and corporate governance practices and procedures. The Company's board of directors, working with outside counsel, investigated and evaluated the allegations in the demand letter and has concluded that pursuing the claims alleged in the demand would not be in the Company's best interests at this time. Proceedings Relating to Shareholder Derivative Complaint On June 29, 2021, an alleged shareholder filed a shareholder derivative complaint in the New York Supreme Court, naming the current and certain former 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 complaint asserts that the individual defendants breached their fiduciary duties in relation to the allegations in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "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 New York Supreme Court to the U.S. District Court for the Southern District of New York. On September 24, 2021, the individual defendants moved to dismiss the complaint in its entirety. Also on September 24, 2021, the plaintiff filed a motion to remand the case to the New York Supreme Court.

As described in greater detail below, the Company is currently a party to patent infringement actions initiated by Amgen Inc. (and/or its affiliated entities) against the Company and/or Sanofi (and/or the Company's and Sanofi's respective affiliated entities) in a number of jurisdictions relating to Praluent. See Note 3 for a description of the Company's and Sanofi's arrangement regarding the costs resulting from or associated with such actions.

In the United States, Amgen has asserted claims of U.S. Patent Nos. 8,829,165 (the "'165 Patent") and 8,859,741 (the "'741 Patent"), and sought a permanent injunction to prevent the Company and the Sanofi defendants from commercial manufacturing, using, offering to sell, or selling within the United States (as well as importing into the United States) (collectively, "Commercializing") Praluent. Amgen also seeks a judgment of patent infringement of the asserted patents, monetary damages (together with interest), costs and expenses of the lawsuits, and attorneys' fees. As described in greater detail under "Second Jury Trial and Appeal" below, on February 11, 2021, the Federal Circuit (as defined below) affirmed the lower court's decision that certain of Amgen's asserted patent claims are invalid based on lack of enablement.

First Jury Trial and Appeal. The first jury trial in this litigation (the "First Trial") was held in the United States District Court for the District of Delaware (the "District Court") from March 8 to March 16, 2016. During the course of the First Trial, the District Court ruled as a matter of law in favor of Amgen that the asserted patent claims were not obvious, and in favor of the Company and the Sanofi defendants that there was no willful infringement of the asserted patent claims by the Company or the Sanofi defendants. On March 16, 2016, the jury returned a verdict in favor of Amgen in the First Trial, finding that the asserted claims of the '165 and '741 Patents were not invalid based on either a lack of written description or a lack of enablement. On October 5, 2017, the United States Court of Appeals for the Federal Circuit (the "Federal Circuit") reversed in part the District Court's decision and remanded for a new trial on the issues of written description and enablement. In addition, it affirmed the District Court's ruling that Amgen's patents were not obvious.

Second Jury Trial and Appeal. On January 3, 2019, the District Court held oral argument in the remanded proceedings on the Company and the Sanofi defendants' motion for judgment on the pleadings regarding Amgen's willful infringement claim. On January 18, 2019, the District Court entered an order (i) denying the Company and the Sanofi defendants' motion for summary judgment on validity, (ii) denying Amgen's motion for partial summary judgment on estoppel, and (iii) granting the Company and the Sanofi defendants' cross-motion for summary judgment on estoppel. On February 8, 2019, the District Court granted the Company and the Sanofi defendants' motion for judgment on the pleadings, thereby dismissing Amgen's claim of willful infringement. The second jury trial in this litigation (the "Second Trial") was held before the District Court in February 2019 to determine the validity of Amgen's asserted patent claims. On February 25, 2019, the jury returned a verdict in the Second Trial generally in favor of Amgen, finding that two claims of the '165 Patent and one claim of the '741 Patent were not invalid. The jury also found that two claims of the '165 Patent were invalid for lack of adequate written description while rejecting the lack of enablement challenges to those two claims. On August 28, 2019, the District Court ruled as a matter of law that Amgen's asserted patent claims are invalid based on lack of enablement. The District Court also conditionally denied the Company and the Sanofi defendants' motion for a new trial. On October 23, 2019, Amgen filed a notice of appeal of the District Court's decision with the Federal Circuit. An oral hearing before the Federal Circuit was held on December 9, 2020. On February 11, 2021, the Federal Circuit affirmed the District Court's decision that certain of Amgen's asserted patent claims are invalid based on lack of enablement. On April 14, 2021, Amgen filed a petition for a rehearing en banc, which was denied on June 21, 2021. On November 18, 2021, Amgen filed a petition for writ of certiorari with the United States Supreme Court.

Injunctive Relief Proceedings. On March 18, 2019, Amgen filed a renewed motion for a permanent injunction to prohibit the Company and the Sanofi defendants from Commercializing Praluent in the United States (a "Permanent Injunction"), and an oral hearing on this motion was held in June 2019. Previously, the Federal Circuit stayed and then vacated a Permanent Injunction granted by the District Court in connection with the First Trial. On August 28, 2019, the District Court dismissed as moot Amgen's renewed motion for a Permanent Injunction.

Amgen has asserted European Patent No. 2,215,124 (the "'124 Patent"), which pertains to PCSK9 monoclonal antibodies, in the countries in Europe discussed below. In October 2020, the '124 Patent claims directed to compositions of matter and medical use relevant to Praluent were ruled invalid based on a lack of inventive step by the Technical Board of Appeal (the "TBA") of the European Patent Office (the "EPO"). This decision impacted each of the infringement proceedings based on the '124 Patent discussed below.

Amgen filed lawsuits in Germany, the United Kingdom, and France in July 2016, July 2016, and September 2016, respectively, against the Company and certain of Sanofi's affiliated entities for infringement of the relevant designation of the '124 Patent in each such jurisdiction; and these lawsuits were dismissed in November 2020, September 2021, and June 2021, respectively. The dismissal in Germany followed an earlier finding of infringement and granting of an injunction, both of which were subsequently overturned. In December 2019, Amgen also filed lawsuits in the Netherlands, Italy, and Spain for infringement of the relevant designation of the '124 Patent in each such jurisdiction; the Company was not named as a defendant in any of these actions, and each of these lawsuits was dismissed in February 2021.

On March 23, 2017, the Company, Sanofi-Aventis U.S. LLC, and Genzyme Corporation initiated an inter partes review ("IPR") in the United States Patent and Trademark Office ("USPTO") seeking a declaration of invalidity of U.S. Patent No. 8,679,487 (the "'487 Patent") owned by Immunex Corporation relating to antibodies that bind the human interleukin-4 receptor and subsequently filed two additional IPR petitions in the USPTO seeking declarations of invalidity of the '487 Patent based on different grounds (the "Additional IPR Petitions"). The Patent Trial and Appeal Board ("PTAB") of the USPTO issued a final written decision on the Additional IPR Petitions on February 14, 2019, invalidating all 17 claims of the '487 Patent as obvious. This decision was subsequently affirmed by the Federal Circuit and Immunex's petition for writ of certiorari was denied by the United States Supreme Court. The '487 Patent expired in May 2020 following Immunex's filing of a terminal disclaimer with the USPTO.

On April 5, 2017, Immunex Corporation filed a lawsuit against the Company, Sanofi, Sanofi-Aventis U.S. LLC, Genzyme Corporation, and Aventisub LLC in the United States District Court for the Central District of California seeking a judgment of patent infringement of the '487 Patent and a declaratory judgment of infringement of the '487 Patent, in each case by the Company's and the other defendants' Commercializing of Dupixent; monetary damages (together with interest); an order of willful infringement of the '487 Patent, which would allow the court in its discretion to award damages up to three times the amount assessed; costs and expenses of the lawsuit; and attorneys' fees. The court subsequently granted a joint stipulation by the parties to stay the litigation pending resolution of the appeals of the PTAB's final written decisions on the Additional IPR Petitions discussed above; and, on August 3, 2021, granted a motion to dismiss the lawsuit, dismissing all of Immunex's claims with prejudice.

On September 30, 2016, Sanofi initiated a revocation proceeding in the United Kingdom to invalidate the U.K. counterpart of European Patent No. 2,292,665 (the "'665 Patent"), another patent owned by Immunex relating to antibodies that bind the human interleukin-4 receptor. At the joint request of the parties to the revocation proceeding, the U.K. Patents Court ordered on January 30, 2017 that the revocation action be stayed pending the final determination of the currently pending EPO opposition proceedings initiated by the Company and Sanofi in relation to the '665 Patent. The oral hearing before the EPO on the oppositions occurred on November 20, 2017, at which the claims of the '665 Patent were found invalid and the patent was revoked. A final written decision of revocation of the '665 Patent was issued by the EPO on January 4, 2018. Immunex filed a notice of appeal of the EPO's decision on January 31, 2018, and an oral hearing before the TBA has been scheduled for March 10–11, 2022. On September 20, 2017 and September 21, 2017, respectively, the Company and Sanofi initiated opposition proceedings in the EPO against Immunex's European Patent No. 2,990,420 (the "'420 Patent"), a divisional patent of the '665 Patent (i.e., a patent that shares the same priority date, disclosure, and patent term of the parent '665 Patent but contains claims to a different invention). The oral hearing before the EPO on the oppositions occurred on February 14–15, 2019, at which the '420 Patent was revoked in its entirety. Immunex filed a notice of appeal of the EPO's decision on May 31, 2019, and an oral hearing before the TBA has been scheduled for March 10–11, 2022. The original patent term of the Immunex patents expired in May 2021.

On January 7, 2021, Chengdu Kanghong Pharmaceutical Group Co., Ltd. ("Chengdu Kanghong") filed an IPR petition in the USPTO against the Company' s U.S. Patent No. 10,464,992 (the "'992 Patent") and a post-grant review ("PGR") petition against the Company's U.S. Patent No. 10,828,345 (the "'345 Patent") seeking declarations of invalidity of the '992 Patent and '345 Patent. On June 23, 2021, Chengdu Kanghong filed motions to dismiss each of these petitions and terminate the respective proceedings, which were granted by the USPTO on June 25, 2021.

On May 5, 2021, Mylan Pharmaceuticals Inc. filed IPR petitions in the USPTO against the Company's U.S. Patent Nos. 9,254,338 (the "'338 Patent") and 9,669,069 (the "'069 Patent") seeking declarations of invalidity of the '338 Patent and the '069 Patent. On November 10, 2021, the USPTO issued a decision instituting both IPR proceedings. On December 9, 2021, Apotex Inc. and Celltrion, Inc. each filed two separate IPR petitions against the Company's '338 and '069 Patents requesting that their IPRs be instituted and joined with the IPR proceedings initiated by Mylan concerning the '338 and '069 Patents.

On June 19, 2020, Novartis Pharma AG, Novartis Pharmaceuticals Corporation, and Novartis Technology LLC (collectively, "Novartis") filed a complaint with the U.S. International Trade Commission (the "ITC") pursuant to Section 337 of the Tariff Act of 1930 requesting that the ITC institute an investigation relating to the importation into the United States and/or sale within the United States after importation of EYLEA pre-filled syringes ("PFS") and/or components thereof which allegedly infringe Novartis’s U.S. Patent No. 9,220,631 (the "'631 Patent"). Novartis also requested a permanent limited exclusion order forbidding entry into the United States of EYLEA PFS or components thereof; a permanent cease-and-desist order from the importation, sale, offer for sale, advertising, packaging, or solicitation of any sale by the Company of EYLEA PFS or components thereof; and a bond should the Company continue to import EYLEA PFS (if found to infringe) during, if applicable, any 60-day Presidential review period (i.e., the period when the President of the United States (or his designee) can disapprove any ITC decision to issue an exclusion order or cease-and-desist order). The ITC instituted the investigation on July 22, 2020 and a trial was scheduled for April 19–23, 2021. On March 26, 2021, the staff attorney appointed by the ITC's Office of Unfair Import Investigations ("OUII")—an independent government party to the case representing the public interest—determined that the '631 Patent is invalid on several grounds. On April 8, 2021, Novartis moved to terminate the ITC investigation in its entirety based on its withdrawal of the complaint; and, on May 3, 2021, the ITC terminated the investigation.

On June 19, 2020, Novartis also filed a patent infringement lawsuit (as amended on August 2, 2021) in the U.S. District Court for the Northern District of New York asserting claims of the '631 Patent and seeking preliminary and permanent injunctions to prevent the Company from continuing to infringe the '631 Patent. Novartis also seeks a judgment of patent infringement of the '631 Patent, monetary damages (together with interest), an order of willful infringement of the '631 Patent (which would allow the court in its discretion to award damages up to three times the amount assessed), costs and expenses of the lawsuits, and attorneys' fees. On July 30, 2020, the court granted the Company's motion to stay these proceedings until a determination in the ITC proceedings discussed above, including any appeals therefrom, becomes final. On June 11, 2021, the court, at the request of Novartis, lifted the stay. On November 5, 2021, the Company filed a motion to stay these proceedings in light of the pending IPR proceeding discussed below. On January 31, 2022, the court denied the Company's motion to stay these proceedings.

On July 16, 2020, the Company initiated two IPR petitions in the USPTO seeking a declaration of invalidity of the '631 Patent on two separate grounds. On January 15, 2021, the USPTO declined to institute an IPR proceeding on procedural grounds in light of the pending ITC investigation discussed above; the other IPR petition has been withdrawn. Following Novartis's motion to terminate the ITC investigation discussed above, on April 16, 2021 the Company filed a new IPR petition seeking a declaration of invalidity of the '631 Patent based on the same grounds that were the basis for the OUII staff attorney's determination discussed above. On October 26, 2021, the USPTO issued a decision instituting the IPR proceeding.

On July 17, 2020, the Company filed an antitrust lawsuit against Novartis and Vetter Pharma International Gmbh ("Vetter") in the United States District Court for the Southern District of New York seeking a declaration that the '631 Patent is unenforceable and a judgment that the defendants' conduct violates Sections 1 and 2 of the Sherman Antitrust Act of 1890, as amended (the "Sherman Antitrust Act"). The Company is also seeking injunctive relief and treble damages. On September 4, 2020, Novartis filed, and Vetter moved to join, a motion to dismiss the complaint, to transfer the lawsuit to the Northern District of New York, or to stay the suit; and on October 19, 2020, Novartis filed, and Vetter moved to join, a second motion to dismiss the complaint on different grounds. On January 25, 2021, the Company filed an amended complaint seeking a judgment that Novartis's conduct violates Section 2 of the Sherman Antitrust Act based on additional grounds, as well as a judgment of tortious interference with contract. On February 22, 2021, Novartis filed, and Vetter moved to join, a motion to dismiss the amended complaint. On September 21, 2021, the court granted Novartis and Vetter's motion to transfer this lawsuit to the Northern District of New York. As a result, this lawsuit was transferred to the same judge that had been assigned to the patent infringement lawsuit discussed above. On November 5, 2021, the Company filed a motion to stay these proceedings in light of the pending IPR proceeding

On December 11, 2020, the Company filed a lawsuit in the United States District Court for the Southern District of New York against the U.S. Department of Health and Human Services, the Secretary of HHS, the Centers for Medicare & Medicaid Services ("CMS"), and the Administrator of CMS seeking declaratory and injunctive relief related to the interim final rule with comment period entitled "Most Favored Nation (MFN) Model" issued on November 20, 2020 by HHS, acting through CMS (the "MFN Rule"). On the same day, the Company filed a motion for a preliminary injunction and temporary restraining order, seeking to prevent implementation of the MFN Rule. On December 22, 2020, the court heard oral argument on the Company's motion for a preliminary injunction and temporary restraining order. On December 31, 2020, the court granted the Company's motion and issued a preliminary injunction. On February 2, 2021, the government stated to the court that the Solicitor General had determined not to appeal the preliminary injunction. On February 10, 2021, the court entered a 90-day stay of the litigation and subsequently extended the stay, with the most recent 60-day extension granted on January 4, 2022. On December 27, 2021, CMS published a final rule that rescinds the MFN Rule effective February 28, 2022.

On May 21, 2020, the Company and Teva Pharmaceutical Industries Limited ("Teva") filed a lawsuit against Rinat Neurosciences Corp. ("Rinat"), a wholly owned subsidiary of Pfizer Inc., in the English High Court of Justice in London, seeking invalidation and revocation of Rinat's European Patent No. 2,270,048 (the "'048 Patent"), European Patent No. 1,871,416 (the "'416 Patent"), and European Patent No. 2,305,711 (the "'711 Patent"), each of which pertains to the use of NGF monoclonal antibodies to treat certain symptoms in patients suffering from osteoarthritis. On July 21, 2020, Rinat filed its defense and counterclaim seeking a declaration of infringement of the '048 Patent by fasinumab. The counterclaim also seeks a permanent injunction, damages, an accounting of profits, and costs and interest. On December 15, 2020, Rinat filed an amended defense and counterclaim seeking a declaration of infringement of the '711 Patent by fasinumab. On May 5, 2021, the court stayed this litigation on terms mutually agreed by the parties.

The '048 Patent is subject to opposition proceedings in the EPO, which were initiated by the Company on August 10, 2016 and two other opponents on August 11, 2016. On January 3, 2018, the Opposition Division of the EPO issued a preliminary, non-binding opinion regarding the validity of the '048 Patent, indicating that it considered the granted patent to be invalid. An oral hearing on the oppositions against the '048 Patent was held on November 29–30, 2018, at which the Opposition Division upheld the validity of the '048 Patent's claims in amended form. The Company filed a notice of appeal to the TBA of the EPO on March 7, 2019. On October 21, 2020, Teva filed a notice of intervention with the TBA to take part in the appeal proceedings as an intervener. An oral hearing before the TBA has been scheduled for April 5–6, 2022.

The '711 Patent is also subject to opposition proceedings in the EPO, which were initiated by the Company on May 1, 2018. On January 31, 2019, the Opposition Division of the EPO issued a preliminary, non-binding opinion regarding the validity of the '711 Patent, indicating that it considered the granted patent to be invalid. An oral hearing on the opposition against the '711 Patent was held on December 3, 2019, at which the Opposition Division upheld the validity of the '711 Patent's claims in amended form. The Company filed a notice of appeal to the TBA on December 20, 2019. On January 29, 2021, Teva filed a notice of intervention with the TBA to take part in the appeal proceedings as an intervener. An oral hearing before the TBA was held on July 29, 2021, at which the '711 Patent was revoked in its entirety.

On October 5, 2020, Allele Biotechnology and Pharmaceuticals, Inc. ("Allele") filed a lawsuit (as amended on April 8, 2021) against the Company in the United States District Court for the Southern District of New York, asserting infringement of U.S. Patent No. 10,221,221 (the "'221 Patent"). Allele seeks a judgment of patent infringement of the '221 Patent, an award of monetary damages (together with interest), an order of willful infringement of the '221 Patent (which would allow the court in its discretion to award damages up to three times the amount assessed), costs and expenses of the lawsuit, and attorneys' fees. On July 16, 2021, the Company filed a motion to dismiss the complaint. An oral hearing has been scheduled for March 2, 2022.

In January 2017, the Company received a subpoena from the U.S. Attorney's Office for the District of Massachusetts requesting documents relating to its support of 501(c)(3) organizations that provide financial assistance to patients; documents concerning its provision of financial assistance to patients with respect to products sold or developed by Regeneron (including EYLEA, Praluent, ARCALYST, and ZALTRAP®); and certain other related documents and communications. 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. On August 24, 2020, the Company filed a motion to dismiss the complaint in its entirety. On December 4, 2020, the court denied the motion to dismiss.

In September 2019, the Company and Regeneron Healthcare Solutions, Inc., a wholly-owned subsidiary of the Company, each received a civil investigative demand ("CID") from the U.S. Department of Justice pursuant to the federal False Claims Act relating to remuneration paid to physicians in the form of consulting fees, advisory boards, speaker fees, and payment or reimbursement for travel and entertainment allegedly in violation of the federal Anti-Kickback Statute. The CIDs relate to EYLEA, Praluent, Dupixent, ZALTRAP, ARCALYST, and Kevzara and cover the period from January 2015 to the present. On June 3, 2021, the United States District Court for the Central District of California unsealed a qui tam complaint 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 the United States and various states (the "State Plaintiffs"), asserting causes of action under the federal False Claims Act and state law. 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 October 29, 2021, the qui tam plaintiffs filed an amended complaint in this matter. On January 14, 2022, the Company filed a motion to dismiss the amended complaint in its entirety.

In June 2021, the Company received a CID from the U.S. Department of Justice pursuant to the federal False Claims Act. The CID states that the investigation concerns allegations that the Company (i) violated the False Claims Act by paying kickbacks to distributors and ophthalmology practices to induce purchase of EYLEA, including through discounts, rebates, credit card fees, free units of EYLEA, and inventory management systems; and (ii) inflated reimbursement rates for EYLEA by excluding applicable discounts, rebates, and benefits from the average sales price reported to CMS. The CID covers the period from January 2011 through June 2021. The Company is cooperating with this investigation.

On December 17, 2020, UnitedHealthcare Insurance Company and United Healthcare Services, Inc. (collectively, "UHC") filed a lawsuit against the Company in the United States District Court for the Southern District of New York alleging UHC has been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. UHC alleges causes of action under state law and the federal Racketeer Influenced and Corrupt Organizations Act (the "RICO Act") and seeks monetary damages and equitable relief. On March 1, 2021, the Company filed a motion to dismiss the complaint in its entirety. On March 25, 2021, UHC filed an amended complaint; and, on April 22, 2021, the Company filed a motion to dismiss this amended complaint in its entirety. On December 29, 2021, this lawsuit was stayed pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts discussed under "Department of Justice Matters" above.

On July 22, 2021, Humana Inc. ("Humana") filed a lawsuit against the Company in the United States District Court for the Southern District of New York alleging Humana has been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. Humana alleges causes of action under state law and the RICO Act and seeks monetary damages and equitable relief. On September 27, 2021, the Company filed a motion to dismiss the complaint in its entirety. On December 29, 2021, this lawsuit was stayed pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts discussed under "Department of Justice Matters" above.

On December 20, 2021, Blue Cross and Blue Shield of Massachusetts, Inc. and Blue Cross and Blue Shield of Massachusetts HMO Blue, Inc. (collectively, "BCBS") filed a lawsuit against the Company in the U.S. District Court for the District of Massachusetts alleging BCBS has been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. BCBS alleges causes of action under state law and the RICO Act and seeks monetary damages and equitable relief.

On or about September 30, 2020, the Company's board of directors received a demand letter from a purported shareholder of the Company. The demand alleges that Regeneron and its shareholders have been damaged by the conduct alleged in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "Department of Justice Matters" above. The demand letter requests that the Company's board of directors investigate alleged breaches of fiduciary duty by its officers and directors and other alleged violations of law and corporate governance practices and procedures; bring legal action against the persons responsible for causing the alleged damages; and implement and maintain an effective system of internal controls, compliance mechanisms, and corporate governance practices and procedures. The Company's board of directors, working with outside counsel, investigated and evaluated the allegations in the demand letter and has concluded that pursuing the claims alleged in the demand would not be in the Company's best interests at this time.

On June 29, 2021, an alleged shareholder filed a shareholder derivative complaint in the New York Supreme Court, naming the current and certain former 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 complaint asserts that the individual defendants breached their fiduciary duties in relation to the allegations in the civil complaint filed by the U.S. Attorney's Office for the District of Massachusetts discussed under "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 New York Supreme Court to the U.S. District Court for the Southern District of New York. On September 24, 2021, the individual defendants moved to dismiss the complaint in its entirety. Also on September 24, 2021, the plaintiff filed a motion to remand the case to the New York Supreme Court.