FDA Proposes Lower Risk Classification for Certain Tuberculosis Tests

The Food and Drug Administration (FDA) has issued a proposed rule today that would encourage the development of a type of test used to detect cases of tuberculosis (TB). This rule would lower the current risk classification for nucleic acid-based tests allowing manufacturers to utilize the faster, more streamlined clearance pathway for medical devices.

Nucleic acid-based tuberculosis tests can detect the presence of copies of tuberculosis bacterium genetic materials (RNA or DNA) in a mucus (sputum) sample obtained from the patient. This allows timely identification of TB disease.

Currently, these tests are Class III (high-risk) devices that require the more rigorous pre-market approval application. In proposing to downclassify to Class II (moderate-risk), the FDA also issued a draft guidance for manufacturers that identifies the risks associated with false positive and false negative test results, the risks to healthcare workers handling specimens, and makes recommendations on how to mitigate those risks. 

The FDA has assessed the risk and benefits of nucleic acid-based diagnostics for TB and believes that we can continue to address their safety and effectiveness through our draft guidance, says Alberto Gutierrez, director of the Office of In Vitro Diagnostic Device Evaluation and Safety in FDAs Center for Devices and Radiological Health. Taken together, these actions will encourage the development of new TB diagnostics while continuing to assure their safety and effectiveness.

Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis that usually attacks the lungs. People infected with TB who also have weakened immune systems are at much higher risk for developing the disease, and the disease can be fatal if left untreated. The disease is a leading killer of people with HIV worldwide.

Not everyone infected with TB develops the disease, and only people with disease can spread TB. 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.

Nucleic acid-based tests, which detect the genetic material of infecting bacteria, can shorten the time needed to diagnose TB disease from one to two weeks to one to two hours.  When used in conjunction with other clinical tests, nucleic acid-based tests can result in earlier treatment, improved patient outcomes, and interrupt further spread of TB.

The Centers for Disease Control and Prevention (CDC) recommends health care providers perform nucleic acid testing on at least one sample of mucus coughed up from the lower airways (sputum) from patients with signs and symptoms of TB disease, when the test result would alter patient treatment or TB control activities.

Improving access to promising new TB tests is critical to advancing TB prevention efforts. New tools for diagnosis, and greater emphasis on tools that will help identify drug resistance, are essential for eliminating TB in the United States, says Kenneth G. Castro, MD, director of the CDCs Division of Tuberculosis Elimination.

General controls include requirements regarding good manufacturing practice, labeling, registering all establishments with the FDA, listing all devices to be marketed and submitting a premarket notification [510(k)] before marketing a device.

However, general controls alone are insufficient to assure safety and effectiveness of Class II and Class III devices. In addition to complying with general controls, Class II devices are also subject to special controls, which may include special labeling, mandatory performance standards, and post-market surveillance.

The FDA is seeking public input on the draft guidance for 90 days. Comments can be submitted online or in writing to: Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, Rm. 1061, Rockville, Md.  20852.