FDA votes to extend review process for PI3K inhibitors

April 22, 2022

A panel of outside advisors for the U.S. FDA has voted that future approvals of cancer-treating phosphatidylinositol-3-kinase (PI3K) inhibitors should be supported by randomized data in addition to just single-arm trials.

The vote was unanimous, with all 16 advisors voting in favor of the change, and one abstaining. The advisors made their decision after a presentation from the agency which discussed the toxicities of PI3K inhibitors and looked at benefit-risk ratios of the drug for patients with certain blood cancers.

PI3K inhibitors, which are a class of drug mainly used in treating advanced cancer, have been under scrutiny lately with concerns raised about whether or not they actually help cancer patients. Although they have good overall response rates, and improve progression-free survival, overall survival data is in some cases worse for patients treated with PI3K than those who were not.

“While the trials show a favorable impact on efficacy end points … the overall survival results are concerning,” said Nicole Gormley, director of the division of hematologic malignancies II in the FDA’s Office of New Drugs.

Gormley, who voted in favor of randomized data, said that in single-arm trials, safety findings and efficacy are difficult to interpret without another treatment for comparison.

Anthony Sung, an associate professor at Duke Medicine, was the only member to abstain saying he was hesitant to vote on something that could impact future clinical development, while noting that the future cannot be predicted.

After reviewing the data, the other members of the advisory board decided that the risks did not outweigh benefits and opted for the longer process.

Currently there are four FDA-approved PI3K inhibitors on the market for hematologic malignancies: Gilead’s Zydelig, Bayer’s Aliqopa, Secura Bio’s Copiktra and TG’s Ukoniq.