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New REGEN-COV (casirivimab and imdevimab) Data Show Supportive Results in Patients Hospitalized with COVID-19

TARRYTOWN, N.Y., Sept. 30, 2021. Regeneron Pharmaceuticals, Inc. today announced that a trial assessing investigational REGEN-COV (casirivimab and imdevimab) in patients hospitalized with COVID-19 met its primary endpoint. Trial results will be presented at IDWeek 2021 today, and show that REGEN-COV significantly reduced viral load in patients hospitalized with COVID-19 who entered the trial without having mounted their own antibody response (seronegative) and required low-flow or no supplemental oxygen (p=0.0172). The trial also had clinical results supportive of the much larger UK RECOVERY trial in hospitalized patients, with numeric improvements observed across all clinical endpoints assessed.

"COVID-19 continues to have a devastating impact on patients, our communities and healthcare systems, and has so far killed more than one in every 500 Americans," said Eleftherios Mylonakis, M.D., Ph.D., primary investigator of the trial and Professor of Medicine, Molecular Microbiology and Immunology, and Director of Infectious Disease at Brown University and the Lifespan hospitals. "We need a multi-faceted approach to best manage the virus' impact, including vaccination and effective treatment when patients become ill. These data show that REGEN-COV can benefit certain patients even after they are hospitalized, reducing the amount of virus and clinical consequences. Taken together with results announced earlier this year from the RECOVERY trial and other studies, these results have the potential to inform personalized care for hospitalized patients with this protean disease that presents with such high clinical variability."

REGEN-COV is an investigational medicine authorized by the U.S. Food and Drug Administration (FDA) under an emergency use authorization to treat people who are at high risk of serious consequences from COVID-19 infection who are either already infected (non-hospitalized) or in certain post-exposure prophylaxis settings. In the U.S., it is not currently authorized in patients who are hospitalized due to COVID-19 infection.

The trial, which was stopped due to slow enrollment after recruiting just over one third the patients originally planned, found that patients who received REGEN-COV (2,400 mg or 8,000 mg) in addition to standard-of-care (SOC) experienced numeric improvements across all clinical endpoints assessed, compared to SOC alone (placebo). Researchers did not observe any clinical difference between the two REGEN-COV doses (2,400 mg or 8,000 mg), or any serious or dose-dependent safety signals in REGEN-COV treated patients. In a safety analysis involving 2,007 patients (REGEN-COV=1,340, placebo=667) serious adverse events occurred in 21% REGEN-COV patients (n=285) and 26% placebo patients (n=174). Infusion-related reactions and hypersensitivity reactions that were grade ≥2 occurred more commonly among REGEN-COV patients (2% and 1% respectively) than placebo patients (1% and <0.5% respectively). The trial originally assessed a broader group of patients; however in late 2020 the trial was adjusted to exclude patients who were on mechanical ventilation or high-flow oxygen at baseline based on a potential safety signal identified by an Independent Data Monitoring Committee in 199 patients on mechanical ventilation or high flow-oxygen, a finding that was not replicated in the much larger RECOVERY trial that enrolled hospitalized patients with a broad range of severe COVID-19, including these patient groups.

"These new results, combined with the nearly 10,000-patient RECOVERY trial, further validate how REGEN-COV can change the course of illness for patients even after they are hospitalized with COVID-19," said George D. Yancopoulos, M.D., Ph.D., President and Chief Scientific Officer at Regeneron. "Patients who received REGEN-COV in this trial experienced a 36% reduced risk of dying within 29 days of receiving treatment, and in patients who were seronegative when they entered the trial the risk was reduced by 56%. It's important to remember that while results from this and the RECOVERY trial indicate that patients unable to develop their own antibodies against COVID-19 historically had the poorest prognosis – and hence the greatest benefit from REGEN-COV treatment – both were largely conducted before widespread vaccination or the emergence of variants such as Delta. Consequently, serostatus may be less informative for treatment decisions in the future because it might not be practical to assess whether patients' antibodies are for their current SARS-CoV-2 infection."

The robust REGEN-COV development program has reported positive Phase 3 trial results across the spectrum of COVID-19 infection, from prevention to hospitalization:

Multiple analyses have shown that the antibody cocktail retains potency against the main variants of concern circulating within the U.S., including Delta (first identified in India), Gamma (first identified in Brazil), Beta (first identified in South Africa) and Mu (first identified in Colombia), with information available in the Fact Sheet for Healthcare Providers. Consequently, REGEN-COV remains available for use across the U.S., and Regeneron will continue actively monitoring the potency of REGEN-COV against emerging variants.

In the U.S., REGEN-COV is available for free to eligible people, as part of a U.S. government funded program and earlier this month Regeneron announced a new agreement with the U.S. government to supply an additional 1.4 million 1,200 mg doses of REGEN-COV. Information on how to access REGEN-COV throughout the U.S. is available from the Department of Health and Human Services and the National Infusion Center Association.

The development and manufacturing of REGEN-COV have been funded in part with federal funds from the Biomedical Advanced Research and Development Authority, part of the U.S. Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response, under OT number: HHSO100201700020C.

About the Trial
The Phase 2/3, randomized, double-blind, placebo-controlled trial evaluated REGEN-COV in hospitalized adult patients with COVID-19. Of the 1,197 patients included in the efficacy analysis, 530 entered the trial with no supplemental oxygen and 667 were on low-flow oxygen. The safety analysis included results from all patients in the efficacy analysis plus additional patients from earlier stages of the clinical program who were on low-flow oxygen at baseline.

Patients were randomized 1:1:1 to receive a one-time infusion of REGEN-COV 8,000 mg, REGEN-COV 2,400 mg or placebo. All patients entering the trial were hospitalized with laboratory-confirmed COVID-19, and all received other background SOC as required including corticosteroids (75%) and remdesivir (55%).

On average, patients included in the efficacy analysis had experienced symptoms for 6 days prior to entering the trial, and nearly half (43%) were seronegative. Approximately 30% were Hispanic and 12% were African American. Patients were on average 62 years of age, 54% were male and 46% were female.

About the REGEN-COV Antibody Cocktail
REGEN-COV (casirivimab and imdevimab) is a cocktail of two monoclonal antibodies that was designed specifically to block infectivity of SARS-CoV-2, the virus that causes COVID-19, using Regeneron's proprietary VelocImmune® and VelociSuite® technologies. The two potent, virus-neutralizing antibodies that form the cocktail bind non-competitively to the critical receptor binding domain of the virus's spike protein, which diminishes the ability of mutant viruses to escape treatment and protects against spike variants that have arisen in the human population, as detailed in Cell and Science.

REGEN-COV has not been approved by the FDA, but is currently authorized in the U.S. for the treatment and post-exposure prophylaxis in certain high risk individuals. Post-exposure prophylaxis with REGEN-COV is not a substitute for vaccination against COVID-19. REGEN-COV is not authorized for pre-exposure prophylaxis for prevention of COVID-19 or for use in patients who are hospitalized due to COVID-19 or require oxygen therapy, or for people currently using chronic oxygen therapy because of an underlying comorbidity who require an increase in baseline oxygen flow rate due to COVID-19. This authorization is for the duration of the declaration that circumstances exist justifying the authorization of the emergency uses under section 564(b)(1) of the Act, 21 U.S.C. § 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner. Additional information about REGEN-COV in the U.S. is below (authorized uses and important safety information).

In August, Regeneron submitted the first of two Biologics License Applications (BLAs) for REGEN-COV. The initial submission included data on the efficacy and safety of REGEN-COV to treat and prevent SARS-CoV-2 infection in non-hospitalized people. The second BLA submission will focus on those hospitalized because of COVID-19, and is expected to be completed later this year.

Emergency or temporary pandemic use authorizations are currently in place in more than 40 countries, including the U.S., several European Union countries, India, Switzerland and Canada, and the antibody cocktail is fully approved in Japan and conditionally approved in the UK.

Regeneron invented REGEN-COV and is collaborating with Roche to increase global supply, with Roche primarily responsible for development and distribution outside the U.S. Regeneron and Roche share a commitment to making the antibody cocktail available to COVID-19 patients around the globe and will support access in low- and lower-middle-income countries through drug donations to be made in partnership with public health organizations.

About Regeneron's VelocImmune Technology
Regeneron's VelocImmune technology utilizes a proprietary genetically engineered mouse platform endowed with a genetically humanized immune system to produce optimized fully human antibodies. When Regeneron's President and Chief Scientific Officer George D. Yancopoulos was a graduate student with his mentor Frederick W. Alt in 1985, they were the first to envision making such a genetically humanized mouse, and Regeneron has spent decades inventing and developing VelocImmune and related VelociSuite technologies. Dr. Yancopoulos and his team have used VelocImmune technology to create approximately a quarter of all original, FDA-approved fully human monoclonal antibodies currently available. This includes REGEN–COV (casirivimab and imdevimab), Dupixent (dupilumab), Libtayo (cemiplimab-rwlc), Praluent (alirocumab), Kevzara (sarilumab), Evkeeza (evinacumab-dgnb) and Inmazeb (atoltivimab, maftivimab and odesivimab-ebgn).

Forward-Looking Statements and Use of Digital Media
This press release includes forward-looking statements that involve risks and uncertainties relating to future events and the future performance of Regeneron Pharmaceuticals, Inc. ("Regeneron" or the "Company"), and actual events or results may differ materially from these forward-looking statements. Words such as "anticipate," "expect," "intend," "plan," "believe," "seek," "estimate," variations of such words, and similar expressions are intended to identify such forward-looking statements, although not all forward-looking statements contain these identifying words. These statements concern, and these risks and uncertainties include, among others, the impact of SARS-CoV-2 (the virus that has caused the COVID-19 pandemic) on Regeneron's business and its employees, collaborators, and suppliers and other third parties on which Regeneron relies, Regeneron's and its collaborators' ability to continue to conduct research and clinical programs, Regeneron's ability to manage its supply chain, net product sales of products marketed or otherwise commercialized by Regeneron and/or its collaborators (collectively, "Regeneron's Products"), and the global economy; the nature, timing, and possible success and therapeutic applications of Regeneron's Products and product candidates being developed by Regeneron and/or its collaborators (collectively, "Regeneron's Product Candidates") and research and clinical programs now underway or planned, including without limitation the development program relating to the REGEN-COVTM (casirivimab and imdevimab) antibody cocktail; the utilization, market acceptance, and commercial success of Regeneron's Products and Regeneron's Product Candidates (such as REGEN-COV), including the impact of recommendations, guidelines, or studies (whether conducted by Regeneron or others and whether mandated or voluntary), such as the study discussed in this press release, on any of the foregoing or any potential regulatory approval of Regeneron's Products and Regeneron's Product Candidates; how long the Emergency Use Authorization ("EUA") granted by the U.S. Food and Drug Administration (the "FDA") for REGEN-COV will remain in effect and whether the EUA is revoked by the FDA based on its determination that the underlying health emergency no longer exists or warrants such authorization or other reasons; whether, based on the data discussed in this press release or otherwise, the EUA for REGEN-COV will be expanded to include treatment of certain patients hospitalized due to COVID-19 infection; the likelihood, timing, and scope of possible regulatory approval and commercial launch of Regeneron's Product Candidates (such as REGEN-COV, including based on the Biologics License Applications filed or planned to be filed with the FDA and referenced in this press release) and new indications for Regeneron's Products; the ability of Regeneron's collaborators, suppliers, or other third parties (as applicable) to perform manufacturing, filling, finishing, packaging, labeling, distribution, and other steps related to Regeneron's Products and Regeneron's Product Candidates (including REGEN-COV) and the impact of the foregoing on Regeneron's ability to supply Regeneron's Products and Regeneron's Product Candidates (including REGEN-COV); the ability of Regeneron to manage supply chains for multiple products and product candidates; safety issues resulting from the administration of Regeneron's Products and Regeneron's Product Candidates (such as REGEN-COV) in patients, including serious complications or side effects in connection with the use of Regeneron's Products and Regeneron's Product Candidates in clinical trials; determinations by regulatory and administrative governmental authorities which may delay or restrict Regeneron's ability to continue to develop or commercialize Regeneron's Products and Regeneron's Product Candidates, including without limitation REGEN-COV; ongoing regulatory obligations and oversight impacting Regeneron's Products, research and clinical programs, and business, including those relating to patient privacy; the availability and extent of reimbursement of Regeneron's Products from third-party payers, including private payer healthcare and insurance programs, health maintenance organizations, pharmacy benefit management companies, and government programs such as Medicare and Medicaid; coverage and reimbursement determinations by such payers and new policies and procedures adopted by such payers; competing drugs and product candidates that may be superior to, or more cost effective than, Regeneron's Products and Regeneron's Product Candidates; the extent to which the results from the research and development programs conducted by Regeneron and/or its collaborators may be replicated in other studies and/or lead to advancement of product candidates to clinical trials, therapeutic applications, or regulatory approval; unanticipated expenses; the costs of developing, producing, and selling products; the ability of Regeneron to meet any of its financial projections or guidance and changes to the assumptions underlying those projections or guidance; the potential for any license, collaboration, or supply agreement, including Regeneron's agreements with Sanofi, Bayer, and Teva Pharmaceutical Industries Ltd. (or their respective affiliated companies, as applicable), as well as Regeneron's collaboration with Roche relating to the casirivimab and imdevimab antibody cocktail (known as REGEN-COV in the United States and Ronapreve™ in other countries) and its REGEN-COV supply agreement with the U.S. government referenced in this press release, to be cancelled or terminated; and risks associated with intellectual property of other parties and pending or future litigation relating thereto (including without limitation the patent litigation and other related proceedings relating to EYLEA® (aflibercept) Injection, Dupixent® (dupilumab), Praluent® (alirocumab), and REGEN-COV), other litigation and other proceedings and government investigations relating to the Company and/or its operations, the ultimate outcome of any such proceedings and investigations, and the impact any of the foregoing may have on Regeneron's business, prospects, operating results, and financial condition. A more complete description of these and other material risks can be found in Regeneron's filings with the U.S. Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2020 and its Form 10-Q for the quarterly period ended June 30, 2021. Any forward-looking statements are made based on management's current beliefs and judgment, and the reader is cautioned not to rely on any forward-looking statements made by Regeneron. Regeneron does not undertake any obligation to update (publicly or otherwise) any forward-looking statement, including without limitation any financial projection or guidance, whether as a result of new information, future events, or otherwise.

SOURCE Regeneron Pharmaceuticals, Inc.

Posted: September 2021

REGEN-COV (casirivimab and imdevimab) FDA Approval History

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