An immunotherapeutic vaccine for multibacillary leprosy.

On January 30, 1998, a vaccine for leprosy based on Mycobacterium w (the code word under which this species hitherto unspecified was investigated) was launched for public use for therapeutic purposes. The vaccine has completed phase III immunotherapeutic trials as an adjunct to chemotherapy in urban and rural leprosy control centres and has received the authorization from the Drugs Controller of India for industrial manufacture. It will be made available by M/s Cadila Pharmaceuticals, Ahmedabad. As an adjunct to chemotherapy, the vaccine expediates bacterial clearance and accelerates clinical regression of lesions. It shortens significantly the period for release from treatment (RFT) of patients. It is effective in inducing a fall of bacterial index (BI) in multibacillary patients who are either nonresponders or slow responders to the standard multidrug therapy and who have persistent BI over long periods. An additional benefit of immunization with this vaccine is the conversion of >60% of LL, 71% of BL and 100% of BB patients from lepromin negativity to lepromin positivity status. A significant number of vaccinated patients showed histopathological upgrading and eventually attainment of a state of nonspecific infiltration without dermal granulomas. The vaccine was well tolerated and the incidence of Type 2 reactions and their severity was less in combined immuno cum chemotherapy group than in the group receiving only chemotherapy. This review describes the nature of the vaccine and the way it was developed.