Twenty five years follow up of MB leprosy patients retreated with a modified MDT regimen after a full course of dapsone mono-therapy

[[[ Background: ]]] The relentless emergence of dapsone resistance amongst M. leprae threatened leprosy control programmes, and increased the relapse rate of patients cured with dapsone monotherapy. [[[ Objective: ]]] The study aimed to analyse the effect on the relapse rate of dapsone-cured multibacillary (MB) leprosy patients, of re-treatment, using a multidrug therapy (MDT) regimen which differed from the WHO recommended regimen. [[[ Design: ]]] 794 MB leprosy patients who had been released from treatment after dapsone monotherapy were selected, amongst them 657 were re-treated for 1 year using the modified multidrug therapy regimen (mMDT) including rifampicin, clofazimine and dapsone, and 137 patients were observed as control cases. [[[ Results: ]]] The regimen was well tolerated with good compliance: 620 patients completed re-treatment with mild side effects and a low incidence of leprosy reactions. There was a statistically significant difference between the relapse rates of re-treated and control groups (chi squaredf = 57.44, P < 0.001). Furthermore, the relapses in the re-treated group were significantly more likely to be later than those in the control group (t = 25.62, P < 0.001). [[[ Conclusions: ]]] Re-treatment with this modified regimen is acceptable and can reduce the risk of early relapse in dapsone-cured patients. The problem of persisters causing late relapse is likely to remain.