MoH, Uganda

NIMR, Tanzania

Impamel III

Abridged schedule for treatment of late stage East African sleeping sickness with melarsoprol (IMPAMEL III)


The treatment of human African trypanosmiasis (HAT) is highly unsatisfactory and melarsoprol (Arsobal®) remains the only available drug to treat the second stage of T.b. rhodesiense HAT. However, its use is hampered by high toxicity and lengthy and complicated treatment schedules. Based on the findings of the IMPAMEL I & II programs an abridged 10-day melarsoprol schedule was recommended for the treatment of second stage T.b. gambiense HAT in 2003. The new schedule demonstrated a clinical non-inferiority over the standard regimens in use but was favorable due to a reduction of the total hospitalization time by 50% and a more economic use of the drug.

However, due to the clinical and epidemiological differences between the two forms of HAT a separate assessment of the safety and efficacy of the 10-day melarsoprol schedule was crucial in order to ensure the safety of the patients. The conduct of the necessary trials was declared a high priority by the WHO.

In the framework of the IMPAMEL III program (2006-2009) a proof-of-concept trial and a utilization study were sequentially conducted in two trial centers in Uganda and Tanzania. The results were compared to historic controls and showed that T.b. rhodesiense patients treated with the 10-day melarsoprol schedule were not subject to a higher incidence of serious adverse events than the historic controls treated with the national regimens.

The 10-day melarsoprol schedule is favored by the patient due to a reduction of the individual hospitalization time from an average of 29 to 13 days. The health system favors it due to the more economic use of the drug and an increase in hospital capacity resulting from the shortened treatment period.
The studies were approved by the ethics committees in Tanzania (National Institute for Medical Research/NIMR) and Uganda (Ministry of Health) and the ethics committee of both cantons of Basel (EKBB), Switzerland.

In September 2009 the results of the IMPAMEL III program will be disseminated at at the 30th International Scientific Council for Trypanosomiasis Research and Control (ISCTRC) Meeting in Uganda. The WHO and the T.b. rhodesiense affected countries will discuss the potential implementation of the 10-day melarsoprol schedule based on these data.

Cattle, main reservoir for T.b. rhodesiense (IK)
Application of Melarsoprol (IK)