US FDA approves Sirturo
As part of a combination therapy to treat adults with multi-drug resistant TB
The US Food and Drug Administration (FDA) has approved Sirturo (bedaquiline) as part of combination therapy to treat adults with multi-drug resistant pulmonary tuberculosis (TB).
According to the US Centers for Disease Control and Prevention, nearly nine million people worldwide and 10,528 people in the US contracted TB in 2011.
Multi-drug resistant TB occurs when Myobacterium tuberculosis, the bacterium that causes the disease, becomes resistant to isonazid and rifampin, two drugs commonly used to treat TB.
The FDA says Sirturo works by inhibiting an enzyme needed by M. tuberculosis to replicate and spread throughout the body.
‘Multi-drug resistant tuberculosis poses a serious health threat throughout the world, and Sirturo provides much-needed treatment for patients who have don’t have other therapeutic options available,’ said Edward Cox, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research. ‘However, because the drug also carries some significant risks, doctors should make sure they use it appropriately and only in patients who don’t have other treatment options.’
Sirturo has been approved under the FDA’s accelerated approval programme, which provides patients with earlier access to promising new drugs while the manufacturer conducts additional studies to confirm the drug’s clinical benefit and safe use. The FDA has also granted Sirturo fast track designation, priority review and orphan-product designation.
Sirturo carries a warning that the drug can affect the heart’s electrical activity (QT prolongation), which could lead to an abnormal and potentially fatal heart rhythm. The warning says 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 patients taking placebo seemed to be related to TB, but no consistent reason for the deaths in the remaining Sirturo-treated patients could be identified, the FDA said.
Sirturo’s manufacturer, Janssen Therapeutics, based in Titusville, NJ, US, will distribute the drug and provide educational materials to help ensure the drug is used appropriately.
Sirturo’s safety and effectiveness were established in 440 patients in two Phase II clinical trials. Both studies measured the length of time it took for a patient’s sputum to be free of M. tuberculosis (sputum culture conversion, or SCC).
Results from the first trial showed patients treated with Sirturo combination therapy achieved SCC in 83 days, compared with 125 days in patients treated with placebo combination therapy. Results from the second trial showed that the average time to SCC was 57 days, supporting the findings of the first trial.