Dr. Christine McKinney, DVM, DACVD, board-certified veterinary dermatologist with Merck Animal Health, joins Dr. Andy Roark to break down a case every vet has seen a hundred times: the young dog stuck in a cycle of recurring ear infections and itching that just won’t quit. Using a real two-year-old golden retriever case, they cover how to work up a chronically allergic dog, when (and when not) to reach for cytology and allergy testing, and how NUMELVI (atinvicitinib tablets), Merck Animal Health’s new JAK1-selective inhibitor approved for dogs as young as six months of age and older, fits into pruritus management alongside elimination diets and infection control. Gang, let’s get into this episode!
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NOTES/LINKS
11:18: “Numelvi targets JAK1, which is the primary driver of itch and inflammation1 in these allergic dogs 10 times selectivity23 compared to, say, JAK2 or any of the other JAK enzymes*.”
– Footnote: *Over the other JAK enzymes in in vitro assays.
– References:
1. Huang IH, Chung WH, Wu PC, Chen CB. JAK-STAT signaling pathway in the pathogenesis of atopic dermatitis: an updated review. Front Immunol._2022;13:1068260. doi:10.3389/fimmu.2022.1068260
2. Kowalski T, Schuette S. The second-generation Janus kinase inhibitor atinvicitinib is a potent and highly selective inhibitor of JAK1. _Vet Dermatol. 2026;0:17. https://doi.org/10.1111/vde.70046
– Reference 2 should show on screen at the 11:25 mark
3. Kowalski T, Schuette S. The second-generation Janus kinase inhibitor atinvicitinib is a potent and highly selective inhibitor of JAK1. Vet Dermatol. 2026;37(2):179.
13:27: “Numelvi has an onset of action, starts working within two to four hours.”
– Footnote: In a canine interleukin-31 (cIL-31)-induced pruritus model.
– Reference: Kowalski T, Prohaczik A, Locke K, et al. The second-generation Janus kinase inhibitor atinvicitinib significantly reduces pruritus 2-4 hours after dosing dogs in a canine interleukin-31 model. Vet Dermatol. 2026;0:17-18. https://doi.org/10.1111/vde.70046
13:37: “In our clinical studies, saw a significant reduction in itch within the first day and that continued through day seven.”
– Footnote: A ≥2 cm reduction in owner Pruritus Visual Analog Scale.
– Reference: Data on File. Study Summary REF-12964. Merck Animal Health.
14:13: “But Numelvi, for those just purely pruritic dogs we start seeing reduction in itch within hours”
– Footnote: In a canine interleukin-31 (cIL-31)-induced pruritus model.
– Reference: Kowalski T, Prohaczik A, Locke K, et al. The second-generation Janus kinase inhibitor atinvicitinib significantly reduces pruritus 2-4 hours after dosing dogs in a canine interleukin-31 model. Vet Dermatol. 2026;0:17-18. https://doi.org/10.1111/vde.70046
15:23: “No known drug interactions with Numelvi.”
– Footnote: No clinically relevant drug interactions observed during 28-day field trial in dogs with allergic dermatitis after use with antimicrobials (including topicals), ecto- and endoparasiticides (isoxazolines, milbemycins, avermectins, pyrethrins, and pyrethroids), analgesics, anesthetics, nutritional supplements, topical skin and ear cleansers that did not contain glucocorticoids, as well as medicated shampoos.
ABOUT OUR GUEST
Dr. Christine McKinney, DVM, DACVD is a Senior Professional Services Veterinarian at Merck Animal Health, where she provides scientific and clinical expertise with a focus on veterinary dermatology. She joined Merck Animal Health in September 2024 after several years in specialty clinical practice. She earned her Doctor of Veterinary Medicine (DVM) from Louisiana State University.
