Clinical problems in the initiation and assessment of multidrug therapy.

The chemotherapy of leprosy needs both to be as effective and also, certainly under field conditions, as safe, cheap, short, acceptable and easy to apply as possible. Now, 4 years after the introduction of the WHO Study Group regimens ! is a very appropriate moment to review progress in multidrug therapy (MDT) . The possibility of MDT of limited duration was pioneered by Professor Freerksen and his colleagues in Malta,2 at the time when the WHO 4th Expert Committee3 had just extended the recommended duration of dapsone monother­ apy in lepromatous leprosy (LL) to ' 1 0 years after achieving inactivity' , i . e . smear negativity. This entailed a total duration of about 20 years of dapsone in severe LL cases, although with the increasing number of relapses then being seen, many due to dapsone resistance, most leprologists were recommending that LL patients should be treated for life . Borderline-tuberculoid (BT) patients were usually treated for around 4-5 years; the time of achieving clinical inactivity was often difficult to determine and the bacteriological end-point, essential for assessing the effectiveness of chemotherapy, was not differentiated from the ending of immunological activity . In the 1 983 assessment of the small and mixed group of Maltese multibacillary leprosy (MBL) patients (mixed because most had received various durations of dapsone therapy before MDT and their sensitivities to dapsone were not investigated), Jopling4 found no case of relapse among 1 1 6 MBL patients studied 5-1 08 months after stopping MDT. The significance of the ' solid' bacilli detected in a few smears was uncertain and warranted further investigation, although the ultimate and significant test of chemotherapeutic effectiveness is and will be the relapse rate . Dr Jopling's update on these selected smear positive patients, S finding no relapses in April 1 986, is therefore of special interest . The second series of data supporting limited duration treatment has been known for some years, but unfortunately is only now in press . In Malaysia, we