Merck's NUMELVI Gets EU Backing as First JAK Inhibitor for Young Dogs

If Approved, NUMELVI Will Be the First and Only Second-Generation Janus Kinase (JAK) Inhibitor for the Treatment of Pruritus Associated with Allergic Dermatitis Including Atopic Dermatitis and Treatment of Clinical Manifestations of Atopic Dermatitis in Dogs

RAHWAY, N.J.--(BUSINESS WIRE)-- Merck Animal Health, known as MSD Animal Health outside of the United States and Canada, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced that the European Medicines Agency’s Committee for Veterinary Medicinal Products (CVMP) issued a positive opinion for NUMELVI™ (atinvicitinib) Tablets for Dogs.

NUMELVI, a once-daily, first-line treatment, will be the only second-generation Janus kinase (JAK) inhibitor indicated for the treatment of pruritus associated with allergic dermatitis including atopic dermatitis and treatment of clinical manifestations of atopic dermatitis in dogs, upon full approval by the European Commission. NUMELVI inhibits the function of JAK1-dependent cytokines involved in itch and inflammation in allergic and atopic dermatitis and is at least 10-fold more selective for JAK1 compared to the other JAK family members (JAK2, JAK3 and TYK2). JAK1 selectivity minimizes interference with cytokines involved in hematopoiesis and immune functions dependent on the other JAKs, resulting in a compelling safety profile with proven efficacy in dogs and puppies. Once approved, it will be the only JAK inhibitor that can be used in dogs as young as six months of age. With a once-daily treatment regimen, NUMELVI is clinically effective after the first dose. Treatment with NUMELVI had no impact on immune response to vaccination.

“Merck Animal Health has been committed to bringing innovation to our customers aimed at rapidly controlling and treating a common condition that causes distress for so many pets and pet owners,” said Rick DeLuca, executive vice president and president, Merck Animal Health. “With today’s positive opinion for NUMELVI, we are one step closer to making this novel, highly selective JAK inhibitor available.”

Itch is seen in more than 20 percent of dogs in general veterinary practice and is one of the most frequent reasons for veterinary visits. As allergic dermatitis progresses, quality of life in dogs declines and the relationship between a pet and its owner can be weakened due to emotional distress, interruptions in sleep and routines, increased expenses, and time lost to provide treatment and veterinary follow-up to manage an itchy dog. Veterinarians also face challenges in managing dogs with allergic dermatitis, as diagnosis and treatment takes time and requires regular progress checks.

“Merck Animal Health continues to deliver cutting-edge innovation and science with first- and best-in-class veterinary medicinal products that address important unmet needs,” said Holger Lehmann, DVM, PhD, vice present and global head, research and development for pharmaceuticals, Merck Animal Health. “NUMELVI not only offers a once-daily dosing regimen but also features a distinctive safety profile that permits its use in dogs as young as six months. Additionally, a vaccine response study has shown that NUMELVI does not affect the immune response to core vaccinations.”

Based on the CVMP’s recommendation, the European Commission is expected to issue a decision for marketing authorization in the European Union (EU) during the third quarter of 2025.

About Merck Animal Health

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than a century, we’ve been at the forefront of research, bringing forward medicines, vaccines and innovative health solutions for the world’s most challenging diseases. Merck Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is the global animal health business of Merck. Through its commitment to The Science of Healthier Animals^®, Merck Animal Health offers veterinarians, farmers, producers, 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 connected technology that includes identification, traceability and monitoring products. Merck 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. Merck Animal Health is present in more than 50 countries, while its products are available in some 150 markets. For more information, visit www.merck-animal-health.com and connect with us on LinkedIn, Facebook, X (formerly Twitter) and Instagram.

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