Shares of Sarepta Therapeutics closed down as much as 42% to hit a nine-year low of $18.30 on Monday after a second death of a male teenage patient who had received its gene therapy, Elevidys, raising doubts on the safety and future demand for the treatment.

WASHINGTON (AP) — Shares of Sarepta Therapeutics plunged Monday after the biotech drugmaker reported a second death in connection with its gene therapy for muscular dystrophy.