Merck, AstraZeneca dip as FDA reviews cancer drug ahead of AdCom meeting
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Shares of Merck (NYSE:MRK) and AstraZeneca (NASDAQ:AZN) fell sharply on Wednesday after the FDA issued briefing documents ahead of an AdCom meeting on a potential label expansion for companies' prostate cancer therapy Lynparza (olaparib).
In December, citing the need for more time to review, the FDA extended its regulatory action date for the companies' supplementary new drug application (sNDA) for Lynparza after initially grating priority review, with a decision expected in Q4 2022.
Lynparza, a PARP inhibitor, is already approved in the U.S. as a late-line option for metastatic castration-resistant prostate cancer (mCRPC) in patients with homologous recombination repair (HRR) gene-mutations such as BRCA-mutations.
With the sNDA, MRK, and AZN had submitted data from their PROpel Phase 3 trial, seeking clearance for Lynparza in combination with Johnson & Johnson's (JNJ) Zytiga (abiraterone) and prednisone or prednisolone to treat adults with mCRPC.
While companies targeted patients with and without BRCA mutations in Lynparza sNDA, the FDA questioned its efficacy for those without BRCA mutations.
"FDA is concerned that efficacy and safety have not been demonstrated outside of the small population of patients with tumor BRCA mutations," the FDA staff wrote in briefing documents released ahead of the AdCom meeting on Friday.
 "â¦.and that the addition of olaparib to abiraterone may cause harm in patients who are definitively negative for tumor BRCA mutations," they explained.
Given the safety concerns, the FDA requests its expert panel on cancer drugs to consider if the approval should be restricted for mCRPC patients with BRCA mutations.
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