Clinical Efficacy & Adverse Effects of Oclacitinib in Cats

In the Literature

Wehber MR, Eisenschenk MC, Young AJ, Koch SN. A retrospective case series reporting the clinical efficacy and adverse events of oclacitinib administration for skin disease in 238 cats. Vet Dermatol. 2026;37(4):557-566. doi:10.1111.vde.70077

The Research …

Treatment of feline atopic skin syndrome (FASS) includes immunomodulatory therapy (eg, cyclosporine, prednisolone), which can be difficult to administer and have significant adverse effects.¹ Subsequently, oclacitinib, a Janus kinase inhibitor approved for use in canine atopic dermatitis, is often administered extra-label to manage FASS. Studies regarding use of this drug in cats are generally limited by small case size and short duration of treatment.^2-13 Optimal dosage and monitoring recommendations are not established, although one pharmacokinetic study suggested cats may respond better to twice-daily administration and to a higher dose than is required for dogs.¹³

This retrospective case series reviewed records of privately owned cats (n = 238) administered oclacitinib by a veterinary dermatologist or dermatology resident. Median treatment duration was 271.5 days (range, 1 day-7.5 years). Patient characteristics (ie, signalment, history, diagnosis), oclacitinib dose, clinical efficacy, and adverse effects were recorded. Primary diagnoses included FASS variants (90.7%), pemphigus foliaceus (7.1%), and other inflammatory skin disorders (2.1%). Commercially available oclacitinib was administered to 91.2% of cats; 7.1% were administered a compounded product, and 1.7% were administered both formulations.

The mean initial oclacitinib dose prescribed was 1.89 mg/kg/day (range, 0.69-3.9 mg/kg/day). A positive therapeutic response was seen in 67.2% of cats, with 61.4% of cats with FASS and 29.3% of cats with pemphigus foliaceus achieving complete remission. Of the cats in complete remission, 59.3% were maintained with twice-daily administration and 40.7% with once-daily administration. Of the cats in complete remission maintained on once-daily administration, 93.3% were originally treated with twice-daily administration. Oclacitinib appeared to be well-tolerated; mild adverse effects (eg, neutropenia [6.3%], GI [3.8%], lethargy [1.7%], infections [0.8%], elevated ALT [0.4%], elevated creatinine [0.4%]) were typically responsive to dose reduction.

… The Takeaways

Key pearls to put into practice:

• Oclacitinib appears to be generally safe and well-tolerated in cats, with adverse effects similar to those reported in dogs.

• A pharmacokinetic study and this case series suggest that cats require higher doses than dogs (mean complete remission dose, 1.56 mg/kg/day) and twice-daily initial administration.¹³

• Blood work monitoring is recommended due to an uncommon occurrence of neutropenia, as well as rare elevations in ALT and creatinine. A reasonable monitoring protocol may be baseline prior to treatment initiation, at 2 and 5 months, then every 6 to 12 months long-term.

• FIV and FeLV testing prior to treatment is recommended. In this study, a patient with FIV required significant dose reduction due to neutropenia. Caution should be taken when prescribing oclacitinib to a patient with FIV or FeLV, and dose reduction should be considered.

• Patients receiving concomitant immunomodulatory medications may be at increased risk for developing infections. In this study, 2 indoor cats treated with concomitant corticosteroids for pemphigus foliaceus developed infections (phaeohyphomycosis [n = 1] and FIP [n = 1]).

• There was no increased risk for neoplasia development in cats treated with oclacitinib in this case series compared with the general population; however, the case series reported 6 cats with documented or possible neoplasia, including 1 cat that developed a mast cell tumor and cutaneous hemangiosarcoma. Caution is warranted when prescribing oclacitinib for a cat with a history of neoplasia.