Sarepta Therapeutics (SRPT) late Thursday announced mixed results for its gene therapy targeting a form of muscular dystrophy, leading SRPT stock to plummet.
In after-hours trading on the stock market today, SRPT stock tanked 51.9% near 81.50.
The biotech company said its gene therapy produced large amounts of a key protein needed for muscle function and strength. That protein is deficient in children born with Duchenne muscular dystrophy. But the increases didn’t lead to statistically significant improvements in muscle function after one year.
Sarepta tested its gene therapy in 41 patients with Duchenne muscular dystrophy. The one-time treatment aimed to increase the amount of the missing protein, called dystrophin. The drug delivers a shortened form of the gene that codes for dystrophin.
SRPT Stock Crumbles On Long-Term Results
At 12 weeks after treatment, patients showed an increased amount of dystrophin in their muscle fibers. But at 48 weeks following treatment, patients who received the gene therapy didn’t show statistically significant improvements in muscle function. That led SRPT stock to crumble.
However, patients who received the gene therapy consistently outperformed those given a placebo, Sarepta said in a news release. Still, SRPT stock plunged as investors questioned the future of the one-time gene therapy.
The news also sent shares of Solid Biosciences (SLDB) tumbling 25.7% near 6.30. Solid Biosciences is also working on a gene therapy to cure Duchenne muscular dystrophy. Pfizer (PFE), which also has a competing gene therapy in the works, fell a fraction to near 37.
Shares of SRPT stock fell to their lowest point since March.
Follow Allison Gatlin on Twitter at @IBD_AGatlin.
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