Three New Antiallergy Drugs Reshape Canine Atopic Dermatitis Care

By Elena Vasquez

Three new antiallergy therapies — ilunocitinib, atinvicitinib and tirnovetmab — have been approved for dogs with allergic dermatitis in the past two years, expanding a treatment arsenal that already included oclacitinib, lokivetmab, cyclosporine and allergen-specific immunotherapy. For practitioners, the arrivals change the conversation at the exam table but not the fundamental task: canine atopic dermatitis remains incurable and demands a lifelong, individually tailored plan.

What do the new JAK inhibitors offer?

All JAK inhibitors approved for veterinary use act as immunomodulators, targeting the JAK enzyme on the cytoplasmic side of cytokine receptors. They deliver rapid pruritus relief, unlike immunotherapy, antihistamines or cyclosporine, and they spare patients the corticosteroid side-effect burden. Caution applies across the class: all carry a recognized risk of secondary infections, and all three U.S. FDA–approved product labels note reported neoplastic conditions without claiming increased neoplasia risk.

Selectivity divides the class. Oclacitinib, FDA-approved in 2013, inhibits JAK1- and JAK3-dependent cytokines involved in allergy, inflammation and pruritus with little effect on JAK2-dependent hematopoiesis. Ilunocitinib is labeled nonselective, with high potency for JAK1, JAK2 and TYK2. Atinvicitinib shows high JAK1 selectivity and is marketed as a second-generation agent.

The marketing outruns the evidence. No true data support claims that selectivity alone predicts safety or efficacy in human or veterinary medicine; current selectivity figures come from cell- and enzyme-based models, with ex vivo data lacking and sometimes contradictory.

One noninferiority study compared ilunocitinib and oclacitinib for pruritus control in atopic dogs. Ilunocitinib proved noninferior. By day 84, 90% of ilunocitinib-treated dogs achieved at least 50% pruritus reduction versus 72% on oclacitinib, and clinical remission — an owner-assessed pruritus score below 2 out of 10 — occurred in 77% versus 53%. No head-to-head studies yet involve atinvicitinib.

Long-term data remain uneven. Oclacitinib carries more than a decade of independent study and pharmacovigilance. A 630-day open-label study of Apoquel (Zoetis), mean duration 407 days, showed quality-of-life improvement in over 91% of dogs and no serious attributable adverse events. Across a 5-year pharmacovigilance period covering more than 91 million dogs, estimated adverse-event frequency fell below 1 per 10,000 treated. Ilunocitinib safety data extend only to 112 days; atinvicitinib, to 28 days.

One regulatory note matters directly for vaccine scheduling. Based on findings in vaccine-naïve puppies given ilunocitinib at three times the labeled dose, the FDA issued a black box warning about inadequate immune response to vaccination. The label directs discontinuation at least 28 days before vaccination and withholding for at least 28 days after. A subsequent study in previously vaccinated dogs showed no significant attenuation of serologic response to adenovirus type 2, parvovirus, distemper and rabies boosters at triple dosing. The decision belongs in an informed discussion with the owner.

Where do monoclonal antibodies fit?

Lokivetmab, a caninized anti–IL-31 monoclonal antibody licensed in 2016, gained company in 2026 when tirnovetmab was licensed with the same indications and mechanism, though it binds IL-31 at a different site. Both bring antipruritic benefit within 24 hours in clinical patients. Lokivetmab is labeled for dosing every 4 to 8 weeks; long-term studies show roughly 45% of dogs need 4-to-5-week intervals, 40% need 6 to 7 weeks, and 15% need 7 to 8 weeks. Tirnovetmab provides 6 to 8 weeks of relief and can be given as often as every 4 weeks.

Adverse events for both — injection-site sensitivity, dermatitis, bacterial skin infection, vomiting, diarrhea, lethargy — are relatively infrequent, with no restrictions on age or concomitant medications. Lokivetmab shows long-term safety with loss of efficacy in up to 17% of patients over time. Comparative lokivetmab-versus-tirnovetmab studies are still needed.

Do steroids and cyclosporine still have a role?

Prednisone/prednisolone at 0.5 to 1 mg/kg PO q24h, initially then tapered, remains reasonable for infrequent acute flares up to 30 days. The cost is real: in one client-satisfaction study, 90% of dogs experienced at least one adverse event by day 14 — polyuria and polydipsia most commonly — and 70% of owners said they would pay more for a therapy with fewer adverse effects. Long-acting injectable corticosteroids are not recommended even acutely, and chronic oral steroid use invites urinary tract infections, hepatopathy, diabetes mellitus and cutaneous changes. Topical steroids reduce systemic exposure but still risk cutaneous atrophy.

Cyclosporine, approved for over 20 years, controls allergic inflammation effectively and safely but needs 4 to 6 weeks, so a 3-week prednisone taper often accompanies initiation. Anecdotally it works when JAK inhibitors and mAbs fail, and it may control concurrent interdigital furunculosis. Its oral liquid formulation permits precise 5 mg/kg dosing and titration, and every-other-day or twice-weekly maintenance is often achievable.

What makes immunotherapy still the anchor?

Allergen-specific immunotherapy remains the only treatment addressing the underlying cause, with success rates of 60% to 70% for the subcutaneous route across four available routes: subcutaneous, sublingual, monthly intralymphatic and once-daily epicutaneous applied to the medial pinna. Benefit takes 3 to 9 months, and therapy should continue at least 12 months before judging efficacy. Nearly one-third of owners do not refill immunotherapy after the initial vials, and success rises significantly with regular veterinary follow-up — strong client education and dermatologist referral are advised.

For acute flares, JAK inhibitors and anti–IL-31 mAbs are the preferred rapid-acting options; JAK inhibitors likely outperform mAbs where moderate to severe inflammation is present, given broader anticytokine activity. Combination rules matter: never combine JAK inhibitors with each other; oclacitinib plus cyclosporine is safe for up to 21 days but not long term; lokivetmab plus oclacitinib showed up to 61% success after monotherapy failure; ASIT has no drug interactions.

No single algorithm fits every atopic dog. As prospective head-to-head data accumulate, practitioners should expect further refinement of which patient factors — age, comorbidities, compliance, cost — favor which anchor therapy.