MSD Animal Health Receives Positive EU CVMP Opinion to Update EXZOLT® SPC for Improving Animal Welfare

First Veterinary Product Centrally Registered in EU to Include Animal Welfare Improvement in its SPC

MADISON, N.J., Jan. 28, 2021 – MSD Animal Health, a division of Merck & Co., Inc., Kenilworth, N.J., USA (NYSE:MRK), today announced that the European Medicines Agency’s Committee for Medicinal Products for Veterinary Use (CVMP)issued a positive opinion for an update to the Summary of Product Characteristics (SPC) for its veterinary medicinal product EXZOLT® (fluralaner) solution for use in drinking water for chickens.

The update to the SPC is based on results from a multi-site EU field study in commercial egg production farms that demonstrated the elimination of poultry red mite (Dermanyssus gallinae) from infested chickens following treatment with EXZOLT was associated with statistically significant improvement in behavioral parameters indicative of animal welfare. These parameters include reduction of night-time activity, head scratching, head shaking and preening at night and during the daytime, as well as a reduction of blood corticosterone concentration.[i] EXZOLT is the first veterinary product centrally registered in the EU to include animal welfare improvement in its SPC.

“Red mite infestations are a major animal welfare threat to chickens and a top-five cause of economic loss in European layer and breeder operations,” said Rik Koopman, director of scientific marketing affairs, MSD Animal Health. “Mite bites cause significant pain and skin irritation, contributing to chronic stress in infested birds characterized by feather pecking, head scratching and decreased weight gain, as well as immunosuppression. Poultry red mites may also act as vectors for chicken pathogens and contribute to disease spread within and between flocks, as well as between chickens and humans. MSD Animal Health is proud to advance EXZOLT as a part of our commitment to The Science of Healthier Animals®, to further decrease the threat of poultry red mite across European farms in addition to preserving the health and well-being of chickens and the people who care for them.”

EXZOLT was the first systemic treatment for poultry red mite infestation, and it is the only poultry product centrally registered in the EU to include data demonstrating improvement in animal welfare within its SPC. EXZOLT is administered via drinking water and begins working against mites within four hours after mites start to feed on treated chickens, resulting in virtual elimination of infestation within production houses of any size or type, including free-range.

About MSD Animal Health

For more than a century, MSD, a leading global biopharmaceutical company, has been inventing for life, bringing forward medicines and vaccines for many of the world’s most challenging diseases. MSD Animal Health, a division of Merck & Co., Inc., Kenilworth, N.J., USA, is the global animal health business unit of MSD. Through its commitment to The Science of Healthier Animals®, MSD Animal Health offers veterinarians, farmers, pet owners and governments one of the widest ranges of veterinary pharmaceuticals, vaccines and health management solutions and services as well as an extensive suite of digitally connected identification, traceability and monitoring products. MSD Animal Health is dedicated to preserving and improving the health, well-being and performance of animals and the people who care for them. It invests extensively in dynamic and comprehensive R&D resources and a modern, global supply chain. MSD Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit www.msd-animal-health.com/ or connect with us on LinkedIn and Twitter.

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. 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 2019 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).

Please see Prescribing Information for EXZOLT® (fluralaner) at [https://www.ema.europa.eu/en/documents/product-information/exzolt-epar-product-information_en.pdf].

[1] Presented at the MSD Animal Health WVPA Congress symposium, “Inventive Solutions for the Hatchery & Breakthrough New Treatment for Poultry Mites, Thursday, September 19, 2019 at the 21st World Veterinary Poultry Association Congress (WVPAC 2019), Bangkok, Thailand.