FDA Approves Fourth-Generation Blood Test

The US Food and Drug Administration (FDA) has approved a next-gen assay for latent tuberculosis (TB) infection that combines breakthrough CD4/CD8 design for comprehensive immune response detection with flexible blood collection workflow.

The FDA approved test QuantiFERON-TB Gold Plus (QFT-Plus) is QIAGEN’s (Germantown, MD, USA, and Hilden, Germany) fourth-generation blood test for detecting latent-TB infection. QFT-Plus builds on the foundation of QuantiFERON-TB Gold (QFT), the third-generation version of Qiagen’s leading interferon gamma release assay (IGRA). QFT is well proven, with a vast body of clinical evidence, as a cost-effective and efficient tool for TB infection testing. Availability in the US is planned to begin later this year (2017).

“We are pleased by the timely FDA approval for QuantiFERON-TB Gold Plus and that we can now bring a range of very attractive clinical and workflow benefits to customers,” said Thierry Bernard, senior VP and head of QIAGEN’s Molecular Diagnostics Business Area, “Tuberculosis is a global disease that is having an impact in the United States as well, where up to 13 million people are infected and nearly 10,000 people are currently suffering with active disease.”

With the addition of proprietary CD8+ technology, QFT-Plus represents a key milestone in the development of diagnostic tests for latent-TB infection. For the first time, a test has the potential to offer the ability to capture a much broader picture of an individual's immune response to TB infection. This technological advancement is critical to improving the understanding of how the immune system reacts to TB infection, and is expected to set a new standard for future disease management.

Among the new features of QFT-Plus is workflow flexibility that allows for even more efficient implementation, especially in large-scale TB screening programs. These include a standard single-tube blood collection option that allows blood samples to be processed up to 53 hours after venipuncture without affecting the accuracy of the test. This adds to the existing, unique "assay in collection tube" design allowing for immediate stimulation of the blood sample.

Another new feature includes advances to support research into the risk-stratification of latent-TB infections developing into active disease based on the first-time incorporation of CD8+ T cell response data, which provides valuable new information by measuring a broader range of immune response. Published scientific evidence underlines the future potential of CD8+ T cells in distinguishing active from latent TB, discerning recent vs. old infections, detecting TB in certain risk populations (such as HIV co-infection and young children), as well as assessing response to TB treatment.

QFT-Plus is set to be released in the US amid new recommendations that are broadening the use of IGRAs. In December 2016, a task force supported by the American Thoracic Society (ATS), US Centers for Disease Control and Prevention (CDC), and Infectious Diseases Society of America published new evidence-based guidelines recommending the use of IGRA tests in wider groups of people at risk for TB infection. This followed recommendations by the US Preventive Services Task Force (USPSTF) in September 2016 that primary care physicians should screen adult patients in groups at high risk for latent TB infection. Both referred to QFT as an FDA-approved IGRA at the time, preferable in certain patient groups to the century-old tuberculin skin test (TST).

Nine independent peer-reviewed publications to date have supported the performance of QFT-Plus, and additional studies underway in 22 countries involve more than 30,000 patients. QFT-Plus is the only IGRA TB test on the pathway to evaluation by the World Health Organization (WHO) as part of its global campaign to eradicate the disease.