- Regeneron and Sanofi are withdrawing an application for Food and Drug Administration approval of their immunotherapy Libtayo in cervical cancer, announcing Friday that they "were not able to align on certain post-marketing studies" with the regulator. Their decision leaves Merck & Co.'s Keytruda as the only drug of its type approved for that indication.
- The companies had hoped to make Libtayo a new option for cervical cancer patients whose tumors return after chemotherapy. However, since Keytruda is already approved for newly diagnosed patients, many second-line patients will have already received an immunotherapy like Libtayo, which could reduce its usefulness.
- Regeneron and Sanofi's withdrawal is the latest in a recent series of regulatory readjustments by drugmakers. It's the second time this week, for instance, that a company has withdrawn a cancer drug application due to differences with regulators on post-approval requirements. On Tuesday, Incyte said the FDA's demands for confirmatory trials didn't "support the investment."
Libtayo was a relative latecomer in the field of cancer immunotherapy, trailing Keytruda and Bristol Myers Squibb's Opdivo to market by four years. As a result, the drug is much less widely used and hasn't been nearly as big a seller for its makers. Regeneron recorded $337 millilion in Libtayo revenue through the first nine months of 2021. Keytruda and Opdivo, by comparison, generate many billions of dollars in sales each year.
A cervical cancer approval might have helped widen the market for Libtayo, however, and the companies had reason to be optimistic. In clinical testing, Libtayo helped patients whose cancer had returned or spread live longer than those receiving chemotherapy. Treatment also helped keep their disease in check.
Libtayo's path, though, appears to be blocked by Keytruda. Merck's drug and Libtayo work the same way — inhibiting a protein called PD-1 that tumors use to evade the immune system. Many of those eligible for Libtayo likely would have already received treatment with Keytruda.
The FDA doesn't disclose communications with companies and Regeneron and Sanofi shared few details on their discussions with the regulators. Still, the agency might be interested in seeing outcomes for patients who get Libtayo after progressing on Keytruda, since such treatment might not be as effective if used a second time. Libtayo showed a benefit in testing regardless of how much PD-1 was expressed on patients' tumors. Higher levels of PD-1 are associated with more frequent responses to immunotherapy.
The setback follows a string of negative news for biotech companies, which have further weighed on the sector's public market performance. In recent weeks, U.S. regulators have stopped clinical tests for two Gilead drugs, an experimental Alzheimer's drug being developed by Cortexyme, a gene therapy for immune deficiency and a drug for a rare neurodegenerative disorder.
Incyte also pulled a cancer drug application on Tuesday amid a push by the FDA to reshape company decisions about pursuing accelerated approvals in cancer.
The seeming uptick in regulatory scrutiny has in turn renewed questions about the FDA's standards and whether it's becoming a tougher regulator in certain areas.