This news release summarizes the results of two clinical trials gauging the efficacy of a new test for tuberculosis — C-Tb. The study compared the new test with a more complex, and expensive, alternative and measures whether the new test works better in patients who are HIV-positive and/or who are vaccinated with the Bacillus Calmette–Guérin (BCG) vaccine. The release provides adequate data for readers to trust its claims but doesn’t mention funding sources or address whether there was any potential for conflicts of interest. To its credit, however, the release includes a basic research abstract providing more detailed information on the results from the trials.
Tuberculosis is a serious problem worldwide and the World Health Organization (WHO) has a stated goal of controlling, if not eradicating, the disease by 2035. As is noted, the most often used test (TST) is associated with a high false positive rate making inappropriate treatment more likely. Given the increasing resistance of the tuberculosis bacteria, a reduction in unnecessary antibiotic treatment is welcomed. Any new test that is more accurate, less expensive and convenient to use will certainly be an asset to that effort.
This release provides a very good discussion of costs, stating, “There is also a dramatic price difference between the two diagnostic tests. According to Dr. Ruhwald, a TST costs about $2; an IGRA is 20 to 40 times more expensive depending on setting.” This gives readers a clear idea of the fiscal advantage of using the new test.
The release provides information that the new test — the C-Tb — is almost as effective as the IGRA, or interferon gamma release assays, which are more expensive, require blood samples and complicated lab work. It also explains that C-Tb is less prone to produce false positives than the TST in BCG-vaccinated individuals. News releases on diagnostic tests should also address the balance between sensitivity — which is how good the test is at positively identifying people who actually have the problem – and specificity – how good the test is at ruling out people who don’t have the problem. This release addresses the specificity issue, stating “The specificity of C-Tb, unlike the TST, was not impacted by the BCG vaccine, the partially effective vaccine that many residents in the developing world receive. TST specificity in this group was only 62 percent. The sensitivity of C-Tb was comparable to the IGRA in confirmed TB cases (77 percent vs. 81 percent), indicating similar abilities to detect infection.”
There is no mention of potential harms with this new test, leaving readers to assume its safety. Although relatively minor, side effects have been noted in previous clinical trials including: “Local adverse reactions following C-Tb injection included transient itching and discomfort as expected components of the immune response.”
In addition, as with most diagnostic tests, there is a risk of false-positive (over-diagnosis) or false-negative (under-diagnosis) results. This should have been mentioned along with data on the test’s reliability.
The release discusses the results of two phase-3 clinical trials comparing the new C-Tb test against existing tests for tuberculosis. It provides specific numerical data comparing the new and existing tests in several categories, and identifies both the number of sites where the trials were held and the number of participants in each trial — information that might give readers more confidence in the reported findings.
The release does not commit disease mongering.
Unfortunately, the release offers no information on either funding sources for these trials or on any possible conflicts of interest that might affect the researchers.
Since the release is showing results of comparisons between existing tests for tuberculosis and the new C-Tb test, there clearly are alternatives, so we’ll give it a satisfactory grade in this category.
The release informs readers that the test still faces a regulatory and commercial path, which strongly implies it is not yet available: “Regulatory approval for C-Tb is currently being sought and Statens Serum Institute is actively seeking a commercial partner for marketing of C-Tb. The cost of a C-Tb test is to be determined; however, it is expected to be significantly less than an IGRA.”
The release basically says that this is a new test that’s cheaper and at least as effective, if not more effective, than existing diagnostic tools — and is less complicated to perform. That certainly qualifies as novel enough for a release.
The release does not appear to use any unjustifiable language.