Dyne Therapeutics shares fell 31.0% in premarket trading without a confirmed company announcement.

While the company is developing treatments for neuromuscular diseases, including z-rostudirsen for Duchenne muscular dystrophy and z-basivarsen for myotonic dystrophy type 1, no specific connection between these programs and the share-price decline was established. The U.S. Food and Drug Administration is currently reviewing a Biologics License Application for z-rostudirsen, with a target action date of January 21, 2027. In its most recent quarter, Dyne Therapeutics reported a net loss of approximately $178.6 million, with a loss per share of $1.08. This figure exceeded the consensus estimate of $0.75 per share. The stock decline occurred while major U.S. equity indices also traded lower, but the decline of Dyne Therapeutics was substantially larger than the moves in the S&P 500, the Dow Jones, and the Nasdaq.