Target product profile for a diagnostic test to detect Mycobacterium leprae infection among asymptomatic household and familial contacts of leprosy patients

Prior to attracting developers and companies to invest in producing innovative diagnostics for leprosy, a TPP is essential to recognize and document gaps, priority areas for diagnostics, use cases, needs statements and requirements for ideal and optimal test scenarios for each of these priority areas.

The Leprosy Diagnostic Working Group of the Global Partnership for Zero Leprosy, in partnership with DTAG and in technical consultation with the Bill & Melinda Gates Foundation, developed this TPP using existing technical and modelling resources to pave a way for a future with effective diagnostics for leprosy.

A point-of-care, field-friendly diagnostic tool is required to detect infection with M. leprae (and M. lepromatosis in ideal cases) among contacts of leprosy cases, especially those who are household or blood-related contacts. Such a diagnostic can detect M. leprae and M. lepromatosis infection at subclinical stage, enabling programmes to intervene with appropriate chemoprophylactic or immunoprophylactic tools to prevent progression to clinical leprosy and curb transmission. However, if clinical leprosy is suspected, the individual should move into an appropriate diagnostic pathway to determine the need for MDT. Given the expansion of PEP interventions in countries endemic for leprosy, a guiding diagnostic tool is essential to decide on those individuals needing enhanced PEP interventions as well as to monitor the effect/efficiency of the intervention at an individual level. This TPP was developed with a view to defining the ideal and optimal characteristics of the diagnostics that will be used to detect M. leprae and M. lepromatosis infection among household and familial contacts of leprosy cases.