RARE Rises as FDA Accepts Resubmitted BLA for Sanfilippo Syndrome

The FDA accepted Ultragenyx's UX111 BLA resubmission, setting a regulatory decision date in September 2026 for a potential first treatment for MPS IIIA. Shares jumped ~5% on the news; the acceptance meaningfully de-risks the program but ultimate value depends on the FDA's upcoming review and approval outcome.

Analysis

The FDA accepted Ultragenyx's UX111 BLA resubmission, setting a regulatory decision date in September 2026 for a potential first treatment for MPS IIIA. Shares jumped ~5% on the news; the acceptance meaningfully de-risks the program but ultimate value depends on the FDA's upcoming review and approval outcome.