A New TB Drug May be Less Likely to Save Lives

by Jennifer Yttri, PhD and Diana Zuckerman, PhD

February 2013

Tuberculosis (TB) is a major cause of death around the world, especially in countries where patients are too poor to receive treatment. Although antibiotics have saved the lives of TB patients for decades, some TB bacteria are now resistant to most antibiotics.  In December 2012, the FDA approved the first new TB drug in 40 years, although the drug is not yet for sale. The new drug will be called Sirturo, also known as bedaquiline.  While this could be a big win for Jannsen, the Johnson & Johnson company that makes it, it may be a loss for patients. The company’s own studies show that patients treated with Sirturo in addition to standard therapy had a 10% higher death rate than patients receiving standard antibiotic therapy alone.  The difference was statistically significant, which means it is very unlikely that it happened by chance.

The FDA will require Sirturo to carry a Black Box that warns about the higher death rate. A Black Box Warning, also used on cigarettes and some risky medical products, is the strongest type of warning that FDA requires.  However, many TB patients won’t know about the warning, and even if they do, what are they to think?  Most patients will assume that the doctor has prescribed Sirturo because it is the best treatment.  They would be shocked to learn that Sirturo may instead be a less effective treatment for TB.

Why is this product approved by the FDA, and what doctor would prescribe an antibiotic that is less likely to save a patient’s life?  The FDA was under pressure to approve it by groups such as the Global Alliance for TB Drug Development, which received funding from Johnson & Johnson to help recruit patients for the clinical trials of Sirturo, and is now suggesting that the higher deaths are just a “bad coincidence” or chance finding.  They don’t seem to understand that the purpose of conducting controlled, randomized trials is to ensure that a statistically significant difference in death or other outcomes is due to the treatment, not due to coincidence or chance.

Sirturo has only been approved for use in combination with other antibiotics that are established as effective treatment for TB. In other words, it is approved as a type of back-up drug, which will substantially add to the cost of treatment.  Sirturo is not yet for sale, so we don’t know how much it will cost. However, new antibiotics always cost much more than older antibiotics, and in this case the cost of the new drug would be added to (rather than instead of) the older, less expensive antibiotics.

Using Sirturo as a back-up drug in case the bacteria are resistant to the older treatment would make sense except that patients taking Sirturo in combination with the established treatment are more likely to die than those taking only the established treatment.

In summary, Sirturo will cost more, patients taking it will be more likely to die, and there is no clear benefit of Sirturo compared to other antibiotic treatments for TB.

The National Research Center for Women & Families has expressed its opposition to the FDA’s approval decision and you can read more about our concerns here.

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