Complete remission of two canine cases with precursor-targeted immune-mediated anemia after combination therapy with prednisolone, cyclosporine, and oclacitinib

Abstract

Background: Precursor-targeted immune-mediated anemia (PIMA) has been described in dogs presenting with
nonregenerative anemia and evidence of ineffective erythropoiesis. Although it has been suggested that its occurrence
may be related to the immune targeting of erythroid precursors, this pathogenesis has not been established. PIMA is
mainly treated with glucocorticoids, and in cases where glucocorticoids alone are not effective, immunosuppressants
are also used as combination therapy. However, not all cases of PIMA go into remission after these treatments.
Case Description: Two dogs with severe nonregenerative anemia diagnosed as PIMA based on the results of clinical
pathological examinations, including bone marrow examination, were treated with whole-blood transfusion and
immunosuppressive doses of prednisolone, mycophenolate mofetil, and cyclosporine. However, these treatments
failed to achieve remission of PIMA. Therefore, concomitant administration of oclacitinib, which is a Janus kinase-1
inhibitor that has been applied recently to the treatment of immune-mediated diseases, was performed; this combined
regimen improved the anemia and achieved complete remission of PIMA.
Conclusion: Oclacitinib may be an option for the treatment of PIMA in dogs failing to achieve remission with
conventional immunosuppressive therapy.