Sirturo (bedaquiline) has been approved by the FDA as part of combination therapy for adults with multi-drug resistant tuberculosis when other alternatives are not possible. This is the first TB medication to be approved in four decades, the FDA informed.

The Food and Drug Administration (FDA) says that Sirturo has been approved for use with older medications for a very hard-to-treat TB strain that has not responded properly to other drugs. The agency added that Sirturo should be prescribed with caution because it carried risks of potentially lethal heart problems.

Multi-resistant tuberculosis is a form of TB that does not respond to isonazid and rifampin – two of the four main antibiotics prescribed for the disease. Sirturo (bedaquiline) is designed specifically for treating multidrug-resistant TB.

Tuberculosis is an infection caused by Mycobacterium tuberculosis. Experts say it is one of the deadliest diseases. Humans spread TB through the air. It usually affects the lungs, but may also affect the brain, kidneys and other parts of the body.

The Centers for Disease Control and Prevention says that in 2011, nearly nine million people worldwide became sick with TB, including 10,528 in the USA.

Bedaquiline inhibits the enzyme that Mycobacterium tuberculosis needs to replicate and spread throughout the human body.

Edward Cox, M.D., M.P.H, director of the Office of Antimicrobial Products in the FDA’s Center for Drug Evaluation and Research, said:

“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. 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.”

Despite nine patients receiving Sirturo in a clinical trial dying compared to two on placebo, the FDA approved Sirturo under its accelerated approval program. In such cases, the Agency can approve new medications based on promising preliminary data while Johnson & Johnson (Janssen Therapeutics), Sirturo’s makers, carries out additional studies to confirm its efficacy and safety.

Sirturo was also granted fast-track designation, priority review and orphan-product designation. The medication showed 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.”

The FDA says Sirturo (bedaquiline) has a Boxed Warning, explaining to patients and doctors that the medication can interfere with the heart’s electrical activity (QT prolongation), which may result in an abnormal and possibly fatal heart rhythm.

All the deaths in the placebo arm of the human studies the FDA examined were linked to tuberculosis. Among the participants taking Sirturo, the causes of four deaths could not be identified, meaning that they might have been related to the drug.

Janssen Therapeutics will provide educational materials to make sure the medication is used properly. The company will distribute the drug from a single source.

The FDA looked at two Phase 2 clinical trials to determine Sirturo’s safety and efficacy.

  • In the first trial, patients were randomly selected to be treated with Sirturo alongside other TB medications, or a placebo alongside other TB medications.
  • In the second trial patients received Sirturo plus other TB medications. This study is ongoing.

In both studies, the aim was to determine how long it took for the patient’s sputum to be free of M. tuberculosis.

In the first trial, the Sirturo-combination therapy patients’ sputum became M. tuberculosis free in 83 days, versus 125 days for those on placebo. The second trial has so far supported the results of the first trial.

During the two trials, the most commonly reported side effects included headache, joint pain and nausea.

Paul Stoffels, M.D., Chief Scientific Officer and Worldwide Chairman, Pharmaceuticals, Johnson & Johnson, said “Sirturo was first discovered in our laboratories more than a decade ago and it is gratifying to see our discovery and development lead to the accelerated approval of the first TB therapy in 40 years with a new mechanism of action. This underscores our commitment as a company to discover, develop and responsibly deliver innovative medicines that address serious unmet medical needs.”

Dr. Lee Reichman, Executive Director of the New Jersey Medical School Global Tuberculosis Institute said that Sirturis is the first MDR-TB (multi-drug resistant tuberculosis) drug, for which the current needs are so great. He described the medication’s approval as an important step in the development of new active ingredients for this “serious and contagious disease”.

The consumer advocacy group, Public Citizen, wrote to the FDA urging the Agency not to approve bedaquiline, because of the dangers linked to the drug which appears in the clinical trials.

In a letter to the FDA, Public Citizen expressed its strong opposition to the accelerated approval of Sirturo because patients on the drug were “five times likely to die than those who took a placebo”.

The letter stated:

“In the face of clinical evidence of increased deaths, including deaths from TB or TB-related causes in patients getting bedaquiline, compared to those getting a placebo, it is not possible to give accelerated approval to the drug.”

Written by Christian Nordqvist