FDA clears Numelvi, adding a new JAK option for itchy dogs

Merck Animal Health has won FDA approval for Numelvi (atinvicitinib tablets), a once-daily oral therapy for the control of pruritus associated with allergic dermatitis in dogs 6 months of age and older. The February 25, 2026 approval gives veterinarians a new JAK inhibitor option in canine dermatology, and Merck is positioning it as the first second-generation, JAK1-selective product in the category. The launch also changes the competitive picture in a space that shifted sharply after FDA approved Elanco’s Zenrelia in September 2024, then later warned veterinarians about vaccine timing, infection risk, and other safety concerns tied to that product. (merck.com)

Why it matters: Allergic skin disease is one of the most common reasons dogs present in general practice, and Merck says skin cases can account for up to 20% of daily caseload in primary care. For veterinary teams, Numelvi’s label stands out because it covers dogs as young as 6 months, starts at 4.4 lb, and, according to the company announcement and dvm360 coverage, does not require vaccination schedule adjustments that became a major practical issue with Zenrelia. That could make treatment planning, client communication, and follow-up simpler for clinics managing chronic itch in younger dogs. The approval also lands as practices are paying closer attention to cost-of-care conversations and insurance workflows more broadly, with industry updates highlighting new direct reimbursement options tied to CareCredit and continued interest in helping clients navigate pet insurance discussions more productively. (merck.com)

What to watch: Watch for Numelvi’s spring 2026 U.S. rollout, early prescribing patterns in general practice, and whether Merck publishes peer-reviewed U.S. clinical data beyond its launch materials. It will also be worth watching how clinics position the drug in real-world allergy care conversations that increasingly include adherence, monitoring, and payment planning for chronic cases. (dvm360.com)