Leprosy research: future targets and priorities
In addition to ofloxacin, two more drugs - minocycline (a tetracycline) and clarithromycin (a macrolide) - have shown very promising anti-leprosy activity in experimental animals and short-term clinical trials. These drugs offer the opportunity to develop and test new regimens which will not only be more effective but also more practicable and acceptable to the patient. The efficacy and safety of combinations of rifampicin, ofloxacin and minocycline as fully supervised, intermittent regimens will be studied in multicentre field trials. Two new protocols have been developed as follows: (a) one dose treatment for single-lesion paucibacillary cases; (b) measuring safety and efficacy of fully-supervised, intermittent drug regimens in the treatment of leprosy. The recruitment of centres for these multicentre field trials will be completed in 1994. The patient intake is likely to continue until the end of 1995. Some of the preliminary results from (a) and (b) are expected to be available by early 1997.
Priorities for research (in collaboration with TDR)
The most important area for research will continue to be the development of better treatment for affected individuals with existing and new drugs. In particular, using the combinations of rifampicin, ofloxacin, clarithromycin and minocycline as fully supervised, intermittent regimens.
Continuing to evaluate the efficacy, acceptability and operational feasibility of ofloxacin-containing multidrug regimens in field trials underway in 15 centres in eight leprosy endemic countries. The impact of HIV infection on the individual patient and the epidemiology of the disease will also need close monitoring. In addition studies to monitor post-treatment relapses and development of resistance to existing and new drugs will be important.
Some major priorities for research in immunology of leprosy will include new diagnostics for detection of early cases, relapses, drug resistance and viability of M.leprae. Evaluation of the immunoprophylactic efficacy of candidate anti-leprosy vaccines in field studies, and assessment of possibilities for immunotherapy will be continued. Studies addressing the significant issue of nerve and tissue damage need further support. To develop more sensitive and specific in vitro systems for M.leprae viability testing, drug screening and drug susceptibility testing. To promote operational research on implementation of WHO/MDT through primary health care, aiming to improve the coverage of MDT in leprosy endemic countries. Studies with skin test antigens, their application and evaluation in the field. Development of PCR-based technology as a tool for epidemiological and clinical studies. The highest priority, however, will remain with research studies in areas which would be directly beneficial for the patients in the community.