Onyx Pharmaceuticals (NASDAQ: ONXX) has announced that they are delaying their NDA filing for FDA approval of carfilzomib—their investigational treatment for refractory/relapsed multiple myeloma—until at least mid-2011. During a pre-NDA meeting, the agency requested more information on the highly selective proteasome inhibitor’s manufacturing process as the company is transitioning from clinical manufacturing to commercial manufacturing.
While preparing for commercial-scale production, Onyx specifically said that relatively routine enhancements to the manufacturing process for carfilzomib were made, however after these enhancements, the company observed minor variations in the handling of the drug that it believes are mainly related to equipment temperature variances. The problem, although considered minor, may not have been cause for an announcement, but Onyx has been planning on getting accelerated approval based on its Phase 2b data.
As a result, Onyx stock sold off over 7% in after-hours trading reflecting that the market does not like the approval process delay. On the other hand, Onyx is only down 2.5% on the NASDAQ today, perhaps reflecting the unwavering potential of the NDA submission. Anthony Coles, MD, CEO of Onyx, said on a conference call that the FDA has not yet signaled whether the Phase 2b data is enough for its review, but he remains confident in the data.
Given the recent problems for Roche/ImmunoGen’s investigational agent trastuzumab-DM1 and their inability to file an NDA based on Phase 2 data in refractory breast cancer patients, we can acknowledge why investors would be nervous about carfilzomib. After the recent string of unapproved FDA decisions, anything negative with FDA in a headline is bound to keep investors at bay.
That being said this appears to be an addressable manufacturing delay, and not a change in the overall filing strategy for Onyx. The American Society of Hematology meeting in December should have more data that supports the filing for carfilzomib in 2011, and should also help assuage investors’ concerns regarding the potential for an accelerated approval.
By John McCamant, Editor of The Medical Technology Stock Letter. You can learn more about MTSL at www.bioinvest.com.
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