Adverse event casts shadow over Neurogene’s Rett syndrome readout

Despite early signs of efficacy in a Phase I/II study of Neurogene’s gene therapy for Rett syndrome, the emergence of a treatment-related serious adverse event spooked investors, and the company appears to be moving only a lower dose forward in pediatric patients.

The safety signal resulted in an abrupt loss of value for Neurogene Inc. (NASDAQ:NGNE), whose shares slipped 44% to $40 on Tuesday, effectively completing a round trip this month. A $200 million PIPE announced Nov. 4 had helped propel the shares to a 52-week high of $74.49 on Friday, up 62% from their last close of $46.07 before the investment...