Tuberculosis diagnostics: which target product profiles should be prioritised?

To the Editor: Globally, a third of all tuberculosis (TB) cases are not notified and many patients do not receive drug susceptibility testing (DST) [1]. New diagnostics can contribute to increased case detection, shorter diagnostic delay and reduced TB transmission. While the Xpert MTB/RIF assay (Cepheid Inc., Sunnyvale, CA, USA) is a much needed breakthrough [2], it may not reach lower tiers of the healthcare system [3] and doesn’t meet all needs ( e.g. cannot detect resistance against multiple drugs). Several promising diagnostics are under development and companies are showing interest in TB products, inspired by the success of Xpert MTB/RIF [4]. But which new TB diagnostics should they invest in, and what is the potential market size for these products? Stakeholders have expressed a need for different products, including a test for childhood TB [5], a simple point-of-care-test for active pulmonary TB [6], a molecular smear replacement test [7], DST for expected new drug regimens [8], predictive biomarkers for latent TB infection (LTBI) [9], and treatment monitoring [10]. Given the variety of these needs, it is important for product developers to have access to: 1) a clearly identified list of diagnostics that are considered high priority by the TB community; 2) well developed, detailed target product profiles (TPPs) for priority diagnostics; and 3) up-to-date market size estimates for the priority TPPs. These issues are being addressed by ongoing activities, supported by the Bill and Melinda Gates Foundation (Seattle, WA, USA) and other partners [3, 7, 11]. TPPs are useful to align the end-users needs …