Sirturo is being approved under the FDA’s accelerated approval program, which allows the agency to approve a drug to treat a serious disease based on clinical data showing that the drug has an effect on a surrogate endpoint that is reasonably likely to predict a clinical benefit to patients. This program provides patients earlier access to promising new drugs while the company conducts additional studies to confirm the drug’s clinical benefit and safe use.
The FDA also granted Sirturo fast track designation, priority review and orphan-product designation. The drug demonstrated the potential to fill an unmet medical need, has the potential to provide safe and effective treatment where no satisfactory alternative therapy exists, and is intended to treat a rare disease, respectively.
Sirturo carries a Boxed Warning alerting patients and health care professionals that the drug can affect the heart’s electrical activity (QT prolongation), which could lead to an abnormal and potentially fatal heart rhythm. The Boxed Warning also notes deaths in patients treated with Sirturo. Nine patients who received Sirturo died compared with two patients who received placebo. Five of the deaths in the Sirturo group and all of the deaths in the placebo arm seemed to be related to tuberculosis, but no consistent reason for the deaths in the remaining Sirturo-treated patients could be identified.
Sirturo’s manufacturer, Janssen Therapeutics, will distribute the drug from a single source and will provide educational materials to help ensure the drug is used appropriately.
Sirturo’s safety and effectiveness were established in 440 patients in two Phase 2 clinical trials. Patients in the first trial were randomly assigned to be treated with Sirturo plus other drugs used to treat TB, or a placebo plus other drugs used to treat TB. All patients in the second trial, which is ongoing, received Sirturo plus other TB drugs. Both studies were designed to measure the length of time it took for a patient’s sputum to be free of M. tuberculosis (sputum culture conversion, or SCC).