The role of oclacitinib in the management of ischaemic dermatopathy in four dogs.

Background Ischaemic dermatopathy represents a heterogenous and poorly-characterized canine syndrome that is often refractory to conventional immunosuppression. Janus-kinase inhibitors (JAKinibs) are used for the treatment of various human autoimmune diseases, including dermatomyositis. Oclacitinib is a generally well-tolerated, veterinary-approved, nonselective JAKinib that has therapeutic potential as an immunosuppressant. Hypothesis/Objectives To describe four cases of treatment refractory juvenile-onset ischaemic dermatopathy that rapidly and durably responded to oclacitinib administration. Animals Four mixed-breed dogs, three 9-month-old male littermates and one 6-month-old female, were presented for generalized patchy alopecia, scarring and ulcerative dermatitis. Microscopic skin lesions were consistent with a severe ischaemic dermatopathy. Methods and materials A complete remission of skin lesions could not be achieved in any dog with glucocorticoids alone, nor when these were combined with adjuvant immunosuppressants. Oclacitinib treatment was then initiated at the dosage of 0.4-0.7 mg/kg twice daily, along with a tapering regimen of oral prednisolone. Results A full clinical remission was achieved within four weeks of starting this combination therapy, with prednisolone being stopped within eight weeks thereof. Remission was maintained in two dogs with lower doses or dosing frequencies of oclacitinib, whereas the two others required persistent twice daily administration of this JAKinib. Conclusions and clinical importance Oclacitinib was a useful immunosuppressive adjuvant to oral glucocorticoids for the treatment of refractory or severe cases of ischaemic dermatopathy in these four dogs. Such observation warrants further studies of the safety, efficacy and mechanism of action of oclacitinib as an immunosuppressant.