The Invitation to Manufacturers of Antituberculosis Medicines to submit an Expression of Interest for Product Evaluation to the WHO Prequalification Unit was recently updated following a request by the WHO Global Tuberculosis Programme.
In particular, the following new formulation of rifampicin was added
- Rifampicin dispersible tablet 100 mg (scored)
Rationale:
WHO/HTH recently commissioned a review of available pharmacokinetic (PK) evidence and pharmacometrics models to potentially inform updated dosing guidance of first-line medicines. The main objective of this work was to perform simulations for dosing for first-line TB medicines (isoniazid, rifampicin, pyrazinamide and ethambutol) fitted into the harmonized weight bands using the currently available fixed dose combinations (FDCs) for adults and children as a priority and if needed with additional top-up with a separate formulation of rifampicin (100 mg scored dispersible tablet) to optimize the dosing of this drug in children.
A Technical Advisory Group on dosing of TB medicines (TAG) of experts in clinical pharmacology, clinical medicine, national TB programmes and civil society and community was established to advise WHO on potential dosing updates for TB medicines, including for prevention and treatment of drug-susceptible TB. The TAG reviewed modelling proposals on dosing and made final decisions on dosing based on harmonized weight or age bands. Among these was a suggestion to use a rifampicin “top‑up” option to achieve optimal drug exposure. Implementing this approach requires the availability of the 100 mg rifampicin dispersible formulation, to be used in combination with the existing paediatric fixed‑dose combination (FDC).