KENILWORTH, N.J.--(BUSINESS WIRE)--$MRK #MRK--Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) regarding Merck�s New Drug Application (NDA) for gefapixant, the investigational, non-narcotic, orally administered selective P2X3 receptor antagonist, under development for the treatment of refractory chronic cough (RCC) or unexplained chronic cough (UCC) in adults. In March 2021, Merck announced that the FDA accepted the company�s NDA for gefapixant. In the CRL, the FDA requested additional information related to measurement of efficacy. The CRL was not related to the safety of gefapixant. Merck is reviewing the letter and will meet with the agency to discuss next steps.

�We remain committed to advancing gefapixant for patients with refractory or unexplained chronic cough and will work with the FDA to address the agency�s feedback,� said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. �We believe there is a significant unmet need to help patients manage their chronic cough, as there are no available treatment options indicated in the U.S. specifically for this condition.�

Last week, the Japan Ministry of Health, Labor and Welfare (MHLW) approved LYFNUA^� (gefapixant) Tablets 45 mg for adults with refractory or unexplained chronic cough. In Japan, LYFNUA is the planned trademark for gefapixant; the trademark for gefapixant in other countries has not been approved. Outside of Japan, gefapixant is an investigational treatment and is still under review by other regulatory bodies.

About Chronic Cough

The prevalence of chronic cough (a cough lasting more than 8 weeks) is estimated to be approximately 5% of adults in the U.S. In a subset of these cases, patients either do not respond to treatment of underlying conditions (such as asthma or gastroesophageal reflux), known as refractory chronic cough (RCC), or they have no identifiable underlying condition despite a thorough evaluation, known as unexplained chronic cough (UCC). There are currently no approved therapies for the treatment of RCC or UCC in the U.S.

About Merck

For over 130 years, Merck, known as MSD outside the United States and Canada, has been inventing for life, bringing forward medicines and vaccines for many of the world�s most challenging diseases in pursuit of our mission to save and improve lives. We demonstrate our commitment to patients and population health by increasing access to health care through far-reaching policies, programs and partnerships. Today, Merck continues to be at the forefront of research to prevent and treat diseases that threaten people and animals � including cancer, infectious diseases such as HIV and Ebola, and emerging animal diseases � as we aspire to be the premier research-intensive biopharmaceutical company in the world. For more information, visit www.merck.com and connect with us on Twitter, Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Kenilworth, N.J., USA

This news release of Merck & Co., Inc., Kenilworth, N.J., USA (the �company�) includes �forward-looking statements� within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company�s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of the global outbreak of novel coronavirus disease (COVID-19); the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company�s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company�s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company�s 2020 Annual Report on Form 10-K and the company�s other filings with the Securities and Exchange Commission (SEC) available at the SEC�s Internet site (www.sec.gov).

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