Safety and efficacy of fumagillin for the treatment of intestinal microsporidiosis. A French prospective cohort study

Abstract

Abstract Background Intestinal microsporidiosis due to Enterocytozoon bieneusi is a cause of chronic diarrhoea in immunocompromised patients. Fumagillin has been approved in France for its treatment. Objectives To investigate the efficacy and safety of fumagillin in a real-life setting. Methods As required by the French Medicine Agency, all patients receiving fumagillin were enrolled in a prospective study to evaluate its efficacy and safety. Stool examination with identification of E. bieneusi by PCR was performed at baseline, end of treatment and monthly thereafter for 6 months. Safety was monitored up to 6 months and full blood counts were monitored up to 42 days after treatment initiation. The primary endpoint was safety. Parasite clearance and relapses were secondary endpoints. Results From 2007 to 2018, 166 patients received fumagillin, including 6 children. Patients were transplant recipients (84%), HIV-infected patients (13%) or had another cause of immunosuppression (5%). Serious adverse events were reported in 41 patients (25%), mainly thrombocytopenia (15%) and neutropenia (5%), with two haemorrhagic events leading to one death. Severe thrombocytopenia (<50 G/L) developed in 50 patients (29.6%), neutropenia (<1 G/L) in 20 patients (11.8%) and severe anaemia (<8 g/dL) in 21 patients (12.4%). At the end of treatment, 94% of patients with available stool examination (n = 132) had no spores detected. Among 99 patients with available follow-up after the end of treatment, three parasite relapses were documented. Conclusions E. bieneusi microsporidiosis was mainly diagnosed in transplant recipients. Fumagillin was associated with haematological toxicity but showed high efficacy with a low relapse rate.