FDA recently issued a draft guidance for companies that are developing new treatments for patients who are in the early stages of Alzheimer’s disease (AD). The recommendations specifically address the selection of patients with early AD, or those who are at risk of developing the disease, for enrollment into clinical trials, as well as what outcomes can be used as primary endpoints.
It can be difficult to determine which patients have early-onset AD, and once selected for a clinical trial, which patients are responding to treatment. One way to track progress of the disease has been to measure levels of biomarkers, such as beta-amyloid protein plaques seen on PET scans.
If these types of biomarker results could be used as a surrogate endpoint, showing effects more precisely and more quickly than cognition and functioning abilities, companies would then be able to bring new treatments to market more quickly and less expensively under an accelerated approval program, as has been the case with many cancer drugs.
FDA, however, said it would not accept biomarker or imaging-based outcomes as a primary endpoint; instead, primary efficacy must reflect a benefit in, preferably, both patients’ cognition and functioning abilities.
“Until there is widespread evidence-based agreement in the research community that an effect on a particular biomarker is reasonably likely to predict clinical benefit, we will not be in a position to consider an approval based on the use of a biomarker as a surrogate outcome measure in AD (at any stage of the illness),” according to the draft guidance.
But, the agency said it is “open to considering the argument that a positive biomarker result (generally included as a secondary outcome measure in a trial) in combination with a positive finding on a primary clinical outcome measure may support a claim of disease modification in AD.”
Released on February 7, the draft guidance is open for comment for 60 days. Following that time frame, FDA will issue a final version.