Combination of eflornithine and melarsoprol for melarsoprol-resistant Gambian trypanosomiasis

Objective: To evaluate the efficacy and toxicity of a combination of eflornithine and melarsoprol among relapsing cases of Gambian trypanosomiasis. Methods: Forty-two late-stage Trypanosoma brucei gambiense trypanosomiasis patients relapsing after initial treatment with melarsoprol were treated with a sequential combination of intravenous eflornithine (100 mg/kg every 6 h for 4 days) followed by three daily injections of melarsoprol (3.6 mg/kg, up to 180 mg). They were then followed-up for 24 months. Results: Two (4.8%) patients died during treatment. Of the 40 surviving patients, two had a treatment failure, 13 and 19 months after having received the combination therapy. By Kaplan-Meier analysis, the 2-year probability of cure was 93.3% (95% confidence interval: 84.3-100%). Conclusion: This sequential combination has an efficacy and a toxicity similar to a 7-day course of eflornithine monotherapy, but is easier to administer. Whether such therapeutic success corresponds to synergism between eflornithine and melarsoprol, or merely means that 4 days of eflornithine monotherapy suffices for such patients, will need to be determined in a comparative trial.