A comparative clinical trial in multibacillary leprosy with long-term relapse rates of four different multidrug regimens.

As a participant in a multicenter trial, we evaluated the relapse rate in 189 multibacillary (MB) leprosy patients treated with four different regimens and followed-up for as many as 12 years after the initiation of treatment. Treatment regimens included 1 year of WHO MDT (a regimen including dapsone, clofazimine, and rifampin), 2 years of WHO MDT, 1 month of daily rifampin and daily ofloxacin, and 1 year of WHO MDT plus an initial 1 month of daily rifampin and daily ofloxacin. Relapse rates after 9 and 12 years from the initiation of therapy in the three regimens that included WHO MDT were 0-3%, whereas relapses occurred in those treated with the 1-month regimen alone at a significantly greater rate (P < 0.05): 11% at 9 years and 25% at 12 years. Relapses occurred late, beginning at 5 years after the initiation of therapy, and were confined to those patients histopathologically borderline lepromatous and polar lepromatous having a high bacterial burden. Prospects for an alternative effective short-course therapy of leprosy are presented.