Chemotherapeutic trials in leprosy. 2. Comparative trial of dapsone plus ditophal (Etisul) and dapsone alone in the treatment of lepromatous leprosy

A controlled clinical trial, using the "double blind " technic, is reported of combined dapsone and ditophal therapy compared with dapsone and placebo in the treatment of pure lepromatous and near lepromatous leprosy. Twenty-five untreated, matched pairs were admitted, and the final analysis was made on 23 pairs and 47 patients studied for one year. Dapsone and ditophal were commenced simultaneously, and over the treatment period 0-1.5 months, a statistically significant (at the 1 per cent level) greater decrease in the percentage of solid-staining bacilli occurred in the smears of pure lepromatous patients treated with ditophal and dapsone than occurred in the smears of patients treated with placebo and dapsone. Therefore, it is evident that combined therapy resulted in a faster rate of killing of leprosy bacilli than did dapsone alone. However, only one method of clinical assessment of the pure lepromatous pairs favored combined therapy; the two other methods of clinical assessment used, and the bacterial index and biopsy index results, all failed to reveal any significant differences between the two treatment groups. In addition, the incidence and severity of erythema nodosum leprosum did not differ in the two groups. Since the more rapid death of bacilli early in treatment had little effect on the rate of improvement of patients after 12 months, the widespread use of ditophal with dapsone does not appear to be justified. Special circumstances are envisaged, however, in which ditophal would be a useful adjunct to treatment. The small number (11) of near-lepromatous patients studied showed a high incidence of lepra reactions, and 4 underwent histologic change during their year in the trial. There was no evidence that the addition of ditophal to dapsone treatment increased the rate of improvement, clinically, histologically or bacteriologically, in this type of leprosy, which, because it is so unstable, appears unsuitable for formal clinical drug trials. Although the majority of the patients included were light-skinned Chinese, no contact dermatitis or other toxic effects of ditophal were observed.