Trials, tribulations, and formulations in access to new TB drugs for children: learning from rifapentine.

Historically, there has been considerable delay between stringent regulatory authority approval for new TB drugs in adults, and subsequent trials, registration, and access for children. This has been due to the exclusion of older children from phase 3 trials, the failure to study novel drugs in younger children earlier on, and delays in developing and testing paediatric formulations. Specific barriers include the failure to develop paediatric investigational plans early on, regulatory barriers, inefficient trial design and implementation, limited site capacity, and lack of advocacy and funding. The successful implementation of paediatric clinical trials depend on timely access to appropriate paediatric formulations. We review the delayed evaluation of rifapentine in children and describe barriers, costs in time and resources, and lost opportunities resulting in delayed clinical trials and access in the field, and highlight avoidable delays. Lessons regarding enablers and inhibitors from the rifapentine experience could prevent similar delays in future.