Low-dose atovaquone for prophylaxis of

Objectives: Methods: This open-label, multicentre, single-arm, phase II trial included patients with connective tissue diseases who were scheduled to start or within 10 days from the initiation of 0.5 mg/kg/d or more of prednisolone or equivalent dose. All patients received low-dose atovaquone for 24 weeks. The primary endpoint was the incidence of PCP at 24 weeks, and adverse events were also assessed as secondary endpoints. Results: Fifty patients were assigned to receive low-dose atovaquone, and 45 were included in the primary analysis. Thirteen patients (28.9%) had comorbidities of lung diseases, and 33 (73.3%) received one or more immunosuppressants or biologics in addition to glucocorticoids during the trial period. No cases of PCP occurred up to 24 weeks. There were 7 nonserious and 2 serious adverse events, including 2 nonserious adverse events possibly related to low-dose atovaquone. Conclusions: Results of this trial suggest that low-dose atovaquone has sufficient efficacy for the prophylaxis of PCP and a good safety profile in patients with connective tissue diseases under glucocorticoid treatments.