Cancer Diagnostics, Clinical Trials and the FDA
If you have any stake in an oncologic or hematologic asset, you are likely familiar with the topic of the significance of cancer diagnostics. Even more so, if your asset is biomarker-driven, especially a non-traditional biomarker, then you are also likely familiar with the significance of the role of Companion Diagnostics (CDx).
It is a common understanding that oncologists treating advanced cancer patients must rapidly progress from insight to action. As such, they need comprehensive, reliable information regarding what exactly might be driving a patient’s cancer. This is because we have an ever-expanding list of targeted options, also termed personalized medicine. There have been massive advances in diagnostics and the development of drugs targeted to the diagnostic indicator. Improvements have come in leaps and bounds in regard to awareness, the adoption of comprehensive genomic profiling (CGP), and clinical accessibility.
This genetic profiling can guide informed decisions on available therapeutic options, most notably those that fall into the targeted therapy category, based on the unique genomic profile of a single patient’s tumor.
Currently, we know of hundreds of relevant genes known to drive cancer, including all guideline-recommended genes in solid tumors and additional genes that may be of relevance for targeted therapies in the future. This number is expected to continue to climb. Most importantly, these diagnostics can provide information on if and when a patient may benefit from a particular therapy. In this scenario, there are FDA-approved companion diagnostics for FDA-approved therapies. The FDA is now more deeply investing in the topic and its role in drug development.
In June, 2023, the FDA announced a new voluntary pilot program for certain oncology drug products used with certain corresponding in vitro diagnostic tests to help clinicians select appropriate cancer treatments for patients. More interestingly, in such, the FDA’s voluntary pilot program is intended to address the risks when targeted cancer treatments are approved without a companion diagnostic.
Companion diagnostic tests analyze human samples for biomarkers to help match patients to specific treatments. Typically, the FDA will approve a CDx and a therapeutic product contemporaneously, but in some circumstances, a cancer therapy that requires the use of a CDx will be approved even if a corresponding test has not yet received marketing authorization (1).
In these cases, healthcare providers may use tests developed by laboratories—a laboratory-developed test to make treatment decisions, which are intended to fill the gap merely but are not necessarily regulated by the FDA in the same way as other in vitro diagnostics (1).
The FDA views such laboratory developed tests as medical devices under its regulatory purview
This is raising concern with FDA over the reliability and accuracy of such results which may be driving critical therapeutic decisions. The FDA previously made a stand on the subject in 2015 when they published 20 case studies highlighting the potential dangers of unauthorized tests, including false negatives in detecting breast cancer and false positives in detecting ovarian cancer.
The FDA views such laboratory-developed tests as medical devices under its regulatory purview but exercises chooses not to enforce it at this time, so such testing developers are not required to submit a test for FDA approval. So how is quality and accuracy validated? They are overseen by the Centers for Medicare and Medicaid Services through the Clinical Laboratory Improvement Amendments (CLIA). The CLIA requires labs to establish a test’s analytical validity when developed without FDA clearance or approva.
So here is the crux of the matter: even though CLIA requires analytical validity to be established, it does not require labs to establish clinical validity. So how accurately does a test identify people with a specific clinical condition or risk (1)? Such laboratory-developed diagnostics must seek FDA approval through the in vitro diagnostic pathway and are required to provide information about both analytical and clinical validity.
The newly announced FDA pilot program is designed to specifically address this regulatory gap and will publish minimum performance characteristics recommended for such diagnostics which are not authorized by the FDA. These will entail performance information for tests that were used to enroll clinical trial patients trials testing subsequently approved therapies and then post to its website the minimum recommended performance characteristics for similar tests that could be used after approval (1). Then, such diagnostic manufacturers can use the published characteristics to guide the development of such tests.
So, all onboard? Not exactly. Many have expressed skepticism that the pilot program will be beneficial for the industry, noting that such lab derived diagnostics are still effectively unregulated regardless of whether companies participate. It is doubted that the FDA will not review any of the tests and thus are effectively legitimizing tests that FDA has never looked at, just taking word value from the manufacturer.
This leaves the manufacturer and corresponding drug developers to rely on their own evaluations of test performance and rely on gathered clinical trial data only.
OncoBay Clinical specializes in early-phase, biomarker-driven immunotherapy cancer trials. We are well-versed in companion diagnostics and co-development CDx strategies. Connect with us to hear more.
Sources:
- Shasteen, H: FDA Pilot Program for Cancer Diagnostics Met with Skepticism, 21Aug23
