FDA allows marketing of Xpert MTB/RIF Assay for treatment of TB

FDA permits marketing of first U.S. test labeled for simultaneous detection of tuberculosis bacteria and resistance to the antibiotic rifampin

The U.S. Food and Drug Administration today allowed marketing of the Xpert MTB/RIF Assay, the first FDA-reviewed test that can simultaneously detect bacteria that cause tuberculosis (TB) and determine if the bacteria contain genetic markers that makes them resistant to rifampin, an important antibiotic for the treatment of TB.

The new test is less complex to perform than other previous FDA-cleared tests for the detection of TB bacteria. Test results, including the detection of TB bacteria and whether the bacteria are drug resistant, are available in approximately two hours. Traditional methods to detect drug resistant TB usually require one to three months.

"Less complex tests such as the Xpert MTB/RIF Assay can be used in more diverse settings," said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological. "The early and rapid detection of rifampin-resistant TB can help curb the spread of drug-resistant TB, a major public health threat."

TB is caused by bacteria that belong to a group known as Mycobacterium tuberculosis complex, which usually attacks the lungs. Not everyone infected with M. tuberculosis develops active TB, and only people with active TB can spread the bacteria to other people. Those with weakened immune systems are at a much higher risk for developing TB once infected with the bacteria, and TB can be fatal if left untreated. TB is a leading killer worldwide of people with HIV.

Common signs and symptoms of TB disease include: a bad cough lasting three weeks or longer, chest pain, coughing up blood, weakness and fatigue, and weight loss.

"New tools, including rapid and accurate diagnostic tests, are critical to advance the fight against TB," said RADM Kenneth G. Castro, M.D., director of CDC's Division of Tuberculosis Elimination. "Early diagnosis and effective treatment for both drug-susceptible and drug-resistant cases are essential for improving patient health, preventing the spread of disease to others, and ultimately, achieving our goal of TB elimination in the U.S."

The FDA reviewed the Xpert MTB/RIF Assay through the de novo classification process, a regulatory pathway for some low- to moderate-risk medical devices that are not substantially equivalent to an already legally marketed device.

In support of the de novo petition the manufacturer submitted data that included an assessment of the test's accuracy in identifying the TB bacteria and the rifampin-resistant strains of the bacteria as compared to validated test methods.

The Xpert MTB/RIF Assay is manufactured and marketed by Cepheid of Sunnyvale, Calif.