FDA: Tissue biopsies used in trials must be justified

The US FDA advises that tissue biopsies in clinical trials should be used only when strictly necessary due to the associated risks.

The US drug regulator made the recommendation last week, explaining that while there are legitimate uses for biopsies in clinical trials, there are some instances where tissue sampling should be avoided.

Richard Pazdur, director of the FDA’s Oncology Center of Excellence, said, “Tissue biopsies in clinical trials are often needed to determine eligibility or to understand the effect of the medical product being studied in the trial.”

The draft guidelines, which were developed by the Oncology Center of Excellence but would also apply to non-cancer drug studies, state biopsies should only be required to gather “information important to the trial,” citing eligibility as an example.

Primary – and key secondary – endpoints are also legitimate reasons to require biopsies in trial protocols under the proposed guidelines.

The FDA writes that when biopsies are the “only way … to evaluate the clinical trial’s primary endpoints or a key secondary endpoint, requiring biopsies as a condition of trial participation may be reasonable.”

In contrast, biopsies used to examine “non-key secondary endpoints and or exploratory endpoints specified in the clinical protocol, or solely for facilitating unspecified future research uses,” should be optional, according to the FDA.

Similarly, for clinical trials involving children, biopsies should only be required if they offer a direct benefit or pose minimal risk.

Risk assessment

The FDA also underlined the need to consider the risk involved in any tissue biopsy included in a trial protocol.

“The degree of risk involved in the biopsy also should be considered, as biopsies of different tissues have inherently different types and levels of risk,” the agency wrote, citing skin shave biopsies and brain tissue biopsies as examples of procedures where the risks are significantly different.

The FDA also stresses the need to consider other approaches. “For tissue sites that pose higher risk, alternative approaches to the biopsy should be considered and a strong scientific justification for the critical need for the biopsy in the clinical trial should be provided.”

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