The National Institutes of Health (NIH) said today that the first clinical trial of a 3-month treatment regimen for tuberculosis (TB) is closing enrollment because of a high rate of unfavorable outcomes.
The randomized controlled CLO-FAST trial sought to evaluate the safety and efficacy of a 3-month regimen containing clofazimine and high-dose rifapentine compared with the standard 6-month regimen. The trial began in November 2021 and had enrolled 104 of 185 planned participants in Haiti, India, Malawi, South Africa, and Zimbabwe.
While the study's independent Data Safety and Monitoring Board (DSMB) determined there were no safety concerns with the investigational regimen, an interim analysis found participants taking the 3-month regimen experienced ongoing or recurring TB rates above thresholds set in the study protocols, which led DSMB to recommend closing enrollment. The National Institute of Allergy and Infectious Diseases, part of the NIH accepted the recommendation.
"Identifying shorter TB treatment regimens is crucial for limiting the spread of infection, reducing drug resistance, improving quality of life for people with TB disease, and reducing demands on health systems worldwide," the NIH said in a news release. "The interim results of the CLO-FAST trial do not support advancing this specific regimen for further evaluation, but the study data will provide essential evidence to inform TB science."
Identifying shorter TB treatment regimens is crucial for limiting the spread of infection, reducing drug resistance, improving quality of life.
NIH noted that participants who were randomized to receive the investigational regiment will complete the treatment as planned, then take an additional 3 months of rifampin and isoniazid. Participants who already successfully completed the regimen will be monitored closely to ensure they remain TB-free.