A Standardized Approach for Collection of Objective Data to Support Outcome Determination for Late-Phase TB Trials.

INTRODUCTION: We developed a standardized method, "Possible poor treatment response" (PPTR), to help ascertain efficacy endpoints in Study S31/A5349 (NCT02410772), an open-label trial comparing two 4-month rifapentine-based regimens with a standard 6-month regimen for the treatment of pulmonary TB. We describe the use of the PPTR process and evaluate whether the goals of minimizing bias in efficacy endpoint assessment and attainment of relevant data to determine outcome for all participants were achieved.

METHODS/DESIGN: A PPTR event was defined as the occurrence of one or more pre-specified triggers. Each PPTR required initiation of a standardized evaluation process that included obtaining multiple sputum samples for microbiology.

RESULTS: Among 2,343 participants with culture-confirmed drug-susceptible TB, 454 individuals (19.4%) had a total of 534 individual PPTR events, of which 76.6% were microbiological (positive smear or culture at or after 17 weeks). At least one PPTR event was experienced by 92.4% (133 of 144) of participants with TB-related unfavorable outcome, and between 13.8 and 14.7% of participants with favorable and not assessable outcomes. 75% of participants with TB-related unfavorable outcomes had microbiological confirmation of failure to achieve disease-free cure.

DISCUSSION: Standardized methodologies, such as our PPTR approach, could facilitate unbiased efficacy outcome determinations, improve discrimination between outcomes that are related and unrelated to regimen efficacy, and enhance the ability to conduct pooled analyses of contemporary trials. Clinical trial registration available at www.

CLINICALTRIALS: gov, ID: NCT02410772.