MSD Animal Health Presented New Data on NUMELVI® (atinvicitinib) Tablets for Dogs and MOMETAMAX ULTRA® (gentamicin, posaconazole, and mometasone furoate otic suspension) for Dogs at the 2025 European Veterinary Dermatology Congress

Rahway, N.J. – Sept. 13, 2025 – MSD Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA (NYSE:MRK), today announced new data demonstrating the safety and efficacy of NUMELVI® (atinvicitinib) Tablets for Dogs and MOMETAMAX ULTRA® (gentamicin, posaconazole, and mometasone furoate otic suspension) for dogs. These data were presented at the 35th European Veterinary Dermatology Congress, September 11-13, 2025 in Bilbao, Spain.

Multiple Studies Highlight the Safety and Efficacy of NUMELVI

            A randomized clinical trial, presented during the Congress under the title “The Second-Generation Janus Kinase 1 Selective Inhibitor Atinvicitinib is a Safe and Effective Once-Daily Treatment For Dogs with Atopic Dermatitis,” evaluated the safety and effectiveness of NUMELVI, a novel treatment for canine atopic dermatitis (CAD), a chronic allergic skin condition triggered by environmental allergens. The study involved client-owned dogs diagnosed with CAD and substantial itching, who received either two different dosing regimens of NUMELVI or a placebo over 28 days. Results showed that NUMELVI was well tolerated with no treatment-related adverse effects and led to a significant reduction in allergy-related clinical signs including pruritus and inflammation. Specifically, 87.5% of dogs receiving 0.8-1.2 mg atinvicitinib/kg once daily throughout the study achieved at least a 50% reduction in itching or skin lesion severity index, compared to only 23.1% in the placebo group. These findings support NUMELVI at the recommended treatment dose of 0.8-1.2 mg/kg once daily as a safe and effective new option for managing atopic dermatitis in dogs.

            A large, randomized, placebo-controlled clinical trial involving 289 client-owned dogs with allergic dermatitis presented during the Congress under the title “The Second-Generation Janus Kinase 1 Selective Inhibitor Atinvicitinib: A Safe and Effective Once-Daily Treatment for Pruritus in Dogs with Allergic Dermatitis” demonstrated that NUMELVI tablets are a safe and effective treatment for controlling itching in dogs suffering from allergic dermatitis. Administered once daily at the recommended treatment dose of 0.8-1.2 mg/kg, NUMELVI was well tolerated with only mild and transient side effects such as vomiting, diarrhea, lethargy and anorexia reported at low rates. Importantly, dogs treated with NUMELVI showed significant reduction in itching compared to placebo, with over 81% experiencing clinically meaningful improvement in itch severity within seven days of once-daily treatment compared to 46.5% in the placebo control group. These results support NUMELVI as a promising therapy for managing pruritus associated with allergic dermatitis in dogs.

“Dermatological conditions are among the most common and challenging health issues affecting dogs,” said Fabiano Orsi da Silva, DVM, MBA, global head of clinical research, MSD Animal Health. “At MSD Animal Health, we recognize the significant impact these conditions have on the well-being of canine companions. That’s why we are deeply committed to ongoing innovation and research in this field, with the goal of developing effective treatments that improve the quality of life for dogs and provide peace of mind for their owners.”

Additional Key Data Presented at the 35th European Veterinary Dermatology Congress include:

  • The second-generation Janus kinase inhibitor atinvicitinib is a potent and highly selective inhibitor of JAK1 (poster)
  • The second-generation Janus kinase inhibitor atinvicitinib significantly reduces pruritus 2-4 hours after dosing dogs in a canine interleukin-31 model (presentation)
  • Protective antibody response to core vaccine antigens in dogs treated with high dose atinvicitinib (poster)
  • One in-clinic dose of gentamicin, posaconazole, and mometasone furoate is safe and effective for treatment of otitis externa associated with susceptible strains of Malassezia pachydermatis, Staphylococcus pseudintermedius and Pseudomonas aeruginosa in dogs (poster)
  • Remote evaluation of activity and behavior in healthy and atopic dogs using a 3-D accelerometer (presentation)

About MSD Animal Health

At MSD, known as Merck & Co., Inc., Rahway, N.J., USA in 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. MSD Animal Health, a division of Merck & Co., Inc., Rahway, N.J., USA, is the global animal health business of MSD. Through its commitment to The Science of Healthier Animals®, MSD 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. 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 and connect with us on LinkedIn and X (formerly Twitter).

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