FDA Denies Regeneron's Blood Cancer Drug, Delaying Rival to J&J and Pfizer

The FDA has caused a significant delay for Regeneron in its quest to compete with Johnson & Johnson and Pfizer in the blood cancer market. The regulatory body issued a complete response letter due to issues found at a third-party manufacturing facility. Regeneron had sought approval for its BCMAxCD3 bispecific antibody, linvoseltamab, based on promising phase 1/2 data for treating relapsed or refractory multiple myeloma. The FDA had initially set an August 22 decision date after accepting the application for priority review. However, at the beginning of August, Regeneron warned that the decision might be postponed beyond the target date due to manufacturing concerns.

On Tuesday evening, Regeneron disclosed that the FDA's complete response letter was tied to problems identified during a preapproval inspection at a third-party fill/finish manufacturer responsible for another company’s product candidate. The third-party manufacturer communicated to Regeneron that it believes the issues raised by the FDA have been addressed and is now waiting for a reinspection to conclude the matter. Regeneron echoed this sentiment during its earnings call earlier this month, indicating that it has been several weeks since the manufacturer implemented the required fixes. The reinspection is anticipated to occur "in the coming months."

During the earnings call, Regeneron's CEO Leonard Schleifer, M.D., Ph.D., remarked that manufacturing-related rejections and issues with third-party fill-finish facilities are common across the industry. He added that the FDA might be planning a public hearing to address these widespread concerns. Regeneron has faced similar setbacks before; its filing for Eylea HD was rejected last year due to inspection findings at a Catalent facility. However, the company managed to secure approval for Eylea HD seven weeks after announcing the rejection. Regeneron is now collaborating with its third-party manufacturer and the FDA to resolve the issues affecting linvoseltamab.

Despite the delay, linvoseltamab has shown promising data that could help it gain a foothold in the multiple myeloma market, even though it has lagged behind competing products. The overall response rate for linvoseltamab stands at 71%, which is higher than the response rates for J&J’s Tecvayli and Pfizer’s Elrexfio. However, these differences may be attributable to variations in the trials rather than the drugs' efficacy. Linvoseltamab's complete response rate is also competitive at 46%.

Regeneron has identified additional advantages of linvoseltamab beyond its efficacy. The company points to the rate and timing of cytokine release syndrome as a differentiating factor. Patients on linvoseltamab may spend fewer days in the hospital compared to those on rival treatments. Regeneron has also explored the possibility of reducing the frequency of dosing, which could further benefit patients.

As the European Medicines Agency continues its review of linvoseltamab, Regeneron is working diligently to address the FDA's concerns and move forward with its plans to introduce the bispecific antibody to the market. The upcoming reinspection of the third-party facility will be a critical step in resolving the current setback and advancing linvoseltamab’s approval process.