TB Notes Newsletter
No. 2, 2013
LABORATORY BRANCH UPDATE
The Federal TB Task Force Diagnostics Workgroup has made substantial progress in several areas. These include Food and Drug Administration (FDA) policy efforts aimed at improving commercial interest in the development of devices that detect M. tuberculosis and related drug resistance. Various activities are coming together to make this happen. For example, progress was reported on the establishment of an FDA and National Institutes of Health (NIH) co-sponsored Frozen Trial Initiative; joint CDC-NIH activity on improving the testing for pyrazinamide (PZA) resistance; the NIH-sponsored TB Diagnostics Research Forum; and CDC and NIH coordination on moving from research to international field tests for the molecular detection of drug resistance.
In March 2012, draft guidance regarding reclassification of nucleic acid TB diagnostic assays was published. Although reclassification was affected by passage of the July 2012 FDA Safety and Innovation Act (FDASIA) policy, progress continues to move forward with reclassification in the context of the new law. On June 19, 2013, the FDA published a Special Controls document asking for public comment within the next 90 days. This document provides guidance to manufactures to make TB diagnostic tests.
Because of the importance of biomarkers for TB treatment efficacy, the FDA and NIH are sponsoring a storage bank of clinical trial frozen specimens (Frozen Trial Initiative) to aid in biomarker discovery. The Consortium for TB Biomarkers currently consists of the TB Alliance, the AIDS Clinical Trial Group, and the TB Trials Consortium. Efforts are underway to store prospectively collected specimens from TB clinical trials.
Similarly, the workgroup is involved in several activities between U.S. agencies and other partners. Much of this activity has focused around improving the accuracy of diagnosis of PZA resistance, because of its important role in both current and future TB drug regimens. There are several ongoing efforts, which include improving PZA testing, improving our understanding of pncA mutations and their role in PZA resistance, enlarging the database of PZA resistant isolates, and promoting cooperation between developers of new molecular diagnostics and the TB drug development field.
Future priorities of the workgroup include understanding molecular markers for resistance of other important drugs besides PZA (e.g., fluoroquinolones and new drugs) for drug-susceptible and drug-resistant TB. They also include improved platforms for rapid resistance testing for drugs other than rifampin, the use of molecular detection of drug resistance for drug resistance surveillance, standardization of laboratory processes for clinical trials, and pediatric diagnostics.
The Xpert MTB/RIF rollout globally is being addressed largely by the International Workgroup of the Federal TB Task Force.
—Reported by Michael F. Iademarco, MD, MPH
Div of TB Elimination
1. FDA background document. Discussion and Recommendations Regarding the Classification of NAAT-based Rapid M. tuberculosis Diagnostics and the Classification of Interferon Gamma Release Assays. Available athttp://www.fda.gov/
2. Summary of PZA Day at CDC. Available athttp://www.newtbdrugs.org/
3. Journal of Infectious Diseases 2012 May 15; Supplement 2: Tuberculosis and Tuberculosis/ HIV/ HIV/AIDS. Table of contents: http://jid.oxfordjournals.org/content/205/suppl_2.toc
4. "Demystifying Pyrazinamide — Challenges and Opportunities" Workshop 2012. September 5 - 6, 2012, Baltimore, Maryland. Information available at http://www.newtbdrugs.org/meetings/pza-workshop-2012.php