Does PET-CT have a role in the evaluation of TB treatment in Phase II Clinical Trials?

Positron Emission Tomography and Computed Tomography (PET-CT) has the potential to revolutionise research in infectious diseases, as it has done with cancer. There is growing interest in it as a biomarker in the setting of early phase tuberculosis clinical trials, particularly given the limitations of current biomarkers as adequate predictors of sterilizing cure for tuberculosis. PET-CT is a real-time tool that provides a three-dimensional view of the spatial distribution of tuberculosis within the lung parenchyma and the nature of lesions with uptake (i.e., whether nodular, consolidative or cavitary). Its ability to provide functional data on changes in metabolism, drug penetration and immune-control of tuberculous lesions has the potential to facilitate drug development and regimen selection for advancement to phase 3 trials in tuberculosis. In this narrative review, we discuss the role PET-CT may have in evaluating responses to drug treatment in active TB treatment and discuss the challenges in taking PET-CT forward as predictive biomarker of relapse free cure in the setting of Phase II clinical trials.