Are 18 doses of WHO/MDT sufficient for multibacillary leprosy; results of a trial in Malawi.

A trial comparing 18 monthly and 30 monthly doses of the World Health Organization-recommended multidrug therapy (WHO/MDT) in 305 multibacillary leprosy patients in Malawi is described. Patients were randomly allocated to one of the two regimens at the time of taking the 18th supervised dose of WHO/MDT. The mean follow-up period was 3 years (maximum 6 years). No relapse was observed in either group. The cumulative probabilities of remaining slit-skin smear positive were significantly higher among patients receiving only the 18 monthly doses of WHO/MDT, but reached zero at month 60 of follow up. The percentage of patients who developed new disabilities during the trial period was similar in both groups. However, the overall percentage of patients who developed new disabilities (50/305, 16.4%) remains disturbingly high. On the whole, the results of the trial argue in favor of 18 monthly doses of WHO/MDT taken within 24 months as being sufficient for the treatment of multibacillary leprosy.