Clinical response to oclacitinib in canine cutaneous epitheliotropic T-cell lymphoma: A case reports

The chemotherapy for canine cutaneous epitheliotropic T cell lymphoma (CETL) might cause unpleasant side effects or fail to produce positive results. We attempted a different approach with a more tolerable treatment option. We administered a high dose of oclacitinib (1.6 mg/kg/twice daily) to a patient diagnosed with CETL through histopathological examination and immunocytochemical staining. The patient had previously shown a poor response to chemotherapy and severe side effects to steroids. Within one month of starting oclacitinib treatment, we observed significant improvement in clinical symptoms, followed by improved appetite, increased activity, and weight gain after 2.5 months. However, subsequently, the patient's condition worsened. Nevertheless, through repeated dose escalation of oclacitinib, the patient was able to survive for 189 days. In terms of tolerability, we observed mild anemia and a decrease in white blood cells when oclacitinib was administered at 3.3 mg/kg/twice daily. However, no abnormalities were seen in blood tests when oclacitinib was administered at 3.0 mg/kg/twice daily, suggesting good tolerance to oclacitinib treatment. In conclusion, despite the safety concerns of high-dose oclacitinib, it did provide an effective and well-tolerated alternative treatment for CETL in dogs.