Abstract
Objectives:
Our objective was to compare the efficacy and safety of three drug combinations for the treatment of late-stage human African trypanosomiasis caused by Trypanosoma brucei gambiense.
Design:
This trial was a randomized, open-label, active control, parallel clinical trial comparing three arms.
Setting:
The study took place at the Sleeping Sickness Treatment Center run by Médecins Sans Frontières at Omugo, Arua District, Uganda
Participants:
Stage 2 patients diagnosed in Northern Uganda were screened for inclusion and a total of 54 selected.
Interventions:
Three drug combinations were given to randomly assigned patients: melarsoprol-nifurtimox (M+N), melarsoprol-eflornithine (M+E), and nifurtimox-eflornithine (N+E). Dosages were uniform: intravenous (IV) melarsoprol 1.8 mg/kg/d, daily for 10 d; IV eflornithine 400 mg/kg/d, every 6 h for 7 d; oral nifurtimox 15 (adults) or 20 (children <15 y) mg/kg/d, every 8 h for 10 d. Patients were followed up for 24 mo.
Outcome Measures:
Outcomes were cure rates and adverse events attributable to treatment.
Results:
Randomization was performed on 54 patients before enrollment was suspended due to unacceptable toxicity in one of the three arms. Cure rates obtained with the intention to treat analysis were M+N 44.4%, M+E 78.9%, and N+E 94.1%, and were significantly higher with N+E (p = 0.003) and M+E (p = 0.045) than with M+N. Adverse events were less frequent and less severe with N+E, resulting in fewer treatment interruptions and no fatalities. Four patients died who were taking melarsoprol-nifurtimox and one who was taking melarsoprol-eflornithine.
Conclusions:
The N+E combination appears to be a promising first-line therapy that may improve treatment of sleeping sickness, although the results from this interrupted study do not permit conclusive interpretations. Larger studies are needed to continue the evaluation of this drug combination in the treatment of T. b. gambiense sleeping sickness.
Background: African trypanosomiasis, or sleeping sickness, is a serious illness that is thought to affect many tens of thousands of people each year in sub-Saharan Africa. The disease is caused by a single-celled parasite that is transmitted to people when they are bitten by an infected Tsetse fly. If the initial phase of the disease is not recognized and treated, the parasite infects the brain, resulting in confusion, sleep problems, and ultimately coma and death. Few treatment options exist, and the most commonly used drug, melarsoprol, is highly toxic; furthermore, parasites are evolving resistance to it in some regions. There is an urgent need to develop new drugs and to evaluate combinations of existing drugs for activity against African trypanosomiasis. Therefore a group of researchers from Epicentre, Médecins Sans Frontières, and the National Sleeping Sickness Control Programme in Uganda performed a trial evaluating the efficacy and safety of three drug combinations. The combinations compared were melarsoprol-nifurtimox, melarsoprol-eflornithine, and nifurtimox-eflornithine, and the researchers planned to recruit 435 people with second-stage African trypanosomiasis in Uganda who would be followed up for 24 months. The primary outcome for the trial was cure rate following treatment. However, once 54 patients had been recruited into the trial, it was obvious that the death rate was much higher among individuals receiving melarsoprol-nifurtimox; the trial was therefore stopped for ethical reasons and this paper reports the results obtained up to that point.
What this trial shows: At follow-up, the cure rate observed for the nifurtimox-eflornithine combination was over twice that for melarsoprol-nifurtimox and substantially higher than that for melarsoprol-eflornithine. Although the number of participants recruited into the trial was much lower than originally planned, the differences in cure rates between nifurtimox-eflornithine and the other two treatments were statistically significant. Deaths and serious adverse events were much more common among patients receiving melarsoprol-nifurtimox than the other two combination therapies.
Strengths and limitations: Trials evaluating treatments for African trypanosomiasis are very rare, and properly randomized studies such as this one provide important data on the efficacy and safety of different treatments. A high proportion of individuals recruited into the trial were followed up for the full two years, and the primary outcome of the trial—the cure rate—was appropriate. A key limitation of the study is that the trial was terminated early; therefore, the differences in efficacy observed in this trial should not be seen as definitive.
Contribution to the evidence: The results from this trial suggest that the nifurtimox-eflornithine combination has potential as a future therapy for stage 2 African trypanosomiasis, and should be evaluated further in clinical trials. Very little other data currently exist on the efficacy and safety of this drug combination.
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