Treatment of idiopathic immune-mediated hemolytic anemia with mycophenolate mofetil in five dogs

The optimal treatment for immune-mediated hemolytic anemia (IMHA) in dogs remains unknown. Mycophenolate mofetil (MMF) is being used with increasing frequency in veterinary medicine for immune-mediated diseases. The goal of this pilot study was to evaluate a series of dogs diagnosed with idiopathic IMHA treated with MMF and other standard therapies. Study endpoints included all cause mortality, hospitalization length, time to resolution of spherocytosis and anemia, time to discontinuation of medications, transfusion requirement, relapse events, and MMF-induced adverse events.

Five dogs diagnosed with idiopathic IMHA received prednisone, MMF, and low-dose aspirin, along with transfusions and supportive therapies as indicated. One dog was euthanized on day 20 for progressive IMHA. One dog was euthanized on day 115 for intolerable MMF-induced gastrointestinal (GI) toxicity. Three dogs survived >1 year beyond the initial diagnosis and are alive at the time of this writing. The median length of hospitalization was 48 hours. The median time to resolution of the spherocytosis and anemia was 13 days and 44 days, respectively. The overall median time to discontinuation of MMF was 165 days. Two dogs required the use of modified cyclosporine (one with MMF, one without MMF). All dogs had suspected MMF-induced GI toxicity, including vomiting, anorexia, or diarrhea; in 2 dogs, these side effects necessitated discontinuation of the MMF.

Although the study demonstrated a potential use of MMF in the induction of remission of IMHA in 4 out of 5 dogs evaluated, the level of significant MMF-induced GI toxicity cannot justify its use with the dosage regime described here.