Neglected Diseases

Leprosy

29K
DALYs in 2019
Disease burden of leprosy

Leprosy, also known as Hansen’s disease, is caused by Mycobacterium leprae and is transmitted via air droplets from the nose or mouth of infected people. Leprosy mainly affects the skin and nerves and has an incubation period that can be as long as 20 years.

The disease is curable with multidrug therapy using a combination of rifampicin, clofazimine and dapsone (for multibacillary leprosy), or rifampicin and dapsone (for paucibacillary leprosy). However, if left untreated, leprosy can cause nerve damage, muscle weakness and permanent impairments.

R&D needs

Drug regimens used for leprosy treatment, though effective, require 6-24 months of treatment. With surveillance data suggesting emergence of resistance to first-line drugs in high-endemic countries, there is a growing need for drugs with simpler regimens and shorter treatments. WHO’s recommendation of single-dose rifampicin as post-exposure prophylaxis constitutes major progress in disease prevention, though we still lack an effective preventive vaccine, with all but one candidate in early-stage development. Leprosy diagnosis is primarily based on clinical criteria and/ or positive microscopy of skin slit specimens. As both methods exhibit suboptimal sensitivity and specificity and rely on individual expertise, novel diagnostic tools are needed. The WHO Diagnostic Technical Advisory Group notes that gaps in the detection of infection, nerve loss function and prediction of future disease need to be addressed. In a proof-of-concept study, a multi-biomarker finger prick point-of-care test showed encouraging results in detecting infection and early-stage disease.

Pipeline spotlight

Dovramilast (previously AMG 634) has received the United States Food and Drug Administration’s Orphan Drug Designation for the treatment of erythema nodosum leprosum. Janssen is currently funding Phase III clinical trials by the Institute of Tropical Medicine, Antwerp, evaluating a combination of Bedaquiline and Rifampicin as post-exposure prophylaxis (PEP) for leprosy in Comoros. Early development of an AI-powered image-based diagnostic tool for leprosy, known as AI4Leprosy, is underway with support from Novartis Foundation and Microsoft.