FDA has scheduled an advisory committee meeting for Tuesday (Oct. 31) to address safety concerns on a high-profile experimental sickle cell treatment called exa-cel developed by Vertex Pharmaceutical and CRISPR Therapeutics. The upcoming meeting suggests FDA's cautious stance towards granting approval for this treatment. The primary concern lies in the adequacy of the sample size used for off-target editing analysis, as revealed in documents released by FDA on Friday (Oct. 27). Exa-cel is the most advanced effort in using the...