An open clinical trial of nifurtimox for arseno-resistant Trypanosoma brucei gambiense sleeping sickness in central Zaire

Twenty-five patients with arseno-resistant Trypanosoma brucei gambiense sleeping sickness were treated with oral nifurtimox, 12-17 mg/kg/d for 60 d. During treatment, trypanosomes disappeared from the cerebrospinal fluid (CSF) of 7/7 patients; the CSF infections; leucocyte was significantly lower at the end of treatment than before it was begun (pre-nifurtimox: 124.2 (+/- 149.3) per microliter; post-nifurtimox: 11.9 (+/- 12.1) per microliter; P less than 0.001). Nifurtimox was well tolerated, with gastro-intestinal disturbances in 6 patients and a reversible cerebellar syndrome in 2 patients. Among the 19 patients seen at least once at follow-up, 12 (63%) relapsed. The other 7 patients have been followed for 3-18 months, and the CSF remained completely normal in 4 of them. This study confirms that nifurtimox has some activity against T.b. gambiense, but a daily dosage higher than 15 mg/kg/d will be necessary to achieve cure of most patients.