Efficacy of new, concise schedule for melarsoprol in treatment of sleeping sickness caused by Trypanosoma brucei gambiense: a randomised trial

Abstract

Background: African trypanosomiasis is a fatal disease caused by protozoan parasites of the species Trypanosoma brucei. The disease has reached epidemic dimensions in various countries of central Africa. Treatment of the second stage is long and complicated, and is hampered by severe adverse reactions to the first-line drug, melarsoprol. Despite these problems, melarsoprol is likely to remain the drug of choice for the next decade. We therefore did a randomised trial comparing the standard treatment schedule with a new, concise regimen.

Methods: The safety and efficacy of the new schedule were assessed in patients presenting to a hospital in Kwanza Norte, Angola with sleeping sickness. The control group followed the 26-day standard Angolan schedule of three series of four daily injections of melarsoprol at doses increasing from 1.2 to 3.6 mg/kg within each series, with a 7-day interval between series. The new treatment schedule comprised 10 daily injections of 2.2 mg/kg. Primary outcomes assessed were elimination of parasites, deaths attributed to treatment, and rate of encephalopathy. Analysis was by intention to treat.

Findings: Of 767 patients with second-stage disease, 500 were enrolled: 250 were assigned the standard schedule, and 250 the new schedule. 40 patients on the standard schedule and 47 on the new schedule had adverse events which resulted in treatment disruption or withdrawal. 50 patients on the standard regimen deviated or withdrew from treatment, compared with two on the new regimen. Parasitological cure 24 h after treatment was 100% in both groups; there were six deaths (all due to encephalopathy) 30 days after treatment in each group. The number of patients with encephalopathic syndromes was also the same in each group (14). Skin reactions were more common with the new treatment, but all could be resolved by additional medication or withdrawal of treatment.

Interpretation: Considering the economic and practical advantages of the new 10-day schedule over the standard 26-day treatment schedule, and the similarity of treatment outcome, the new schedule is a useful alternative to the present standard, especially in epidemic situations and in locations with limited resources.