Du's gene therapy late-stage trial fails, precision gene leader Sarepta plunges over 39% in after-hours trading

According to the Zhitong Finance APP, after the late-stage clinical trials of two gene therapies for Duchenne muscular dystrophy (DMD), AMONDYS 45 (casimersen) and VYONDYS 53 (golodirsen), failed to meet their primary endpoints, the stock price of the globally renowned biotech company Sarepta Therapeutics (SRPT.US), which focuses on rare disease therapies, plummeted significantly, dropping over 39% in after-hours trading.

The clinical trial included a group of 225 boys aged 6 to 13 who had a specific Duchenne mutation that could be addressed by skipping exon 45 or 53.

The biotech company stated that this nine-year study faced severe challenges due to the COVID-19 pandemic, which significantly impacted the participants and the overall trial results.

In terms of safety, the company's overall research demonstrated good and stable safety characteristics observed over the years in exon-skipping therapies.

Sarepta also reported a slight decline of approximately 14.5% in its third-quarter revenue, totaling $399 million, but this was $62.37 million higher than Wall Street analysts' general expectations.

Sarepta Therapeutics is a biotech company headquartered in Cambridge, Massachusetts, USA, positioned to develop precision genetic medicine. Its core and most well-known business area/biotech route focuses on rare hereditary muscle diseases, particularly targeting Duchenne muscular dystrophy (DMD) and certain limb-girdle muscular dystrophies (LGMD).

Sarepta's commercial products and R&D pipeline are primarily centered around DMD/muscular dystrophy, with two main technical routes: the first is RNA exon-skipping therapy, which utilizes PMO and other oligonucleotide technologies to allow the DMD gene to "skip" mutated exons, thereby restoring a portion of the shortened dystrophin protein; the second route is gene therapy (AAV vector), represented by Elevidys, which is the first FDA-approved gene therapy product for Duchenne muscular dystrophy, used for specific DMD patients. However, this line has faced significant safety and regulatory pressures over the past year (multiple cases of liver failure deaths, FDA requests to halt shipments/clinical trials, etc.).

The sharp decline in Sarepta's stock price after hours is primarily due to the critical failure of the Phase III clinical trials combined with a sharp increase in pipeline uncertainty, rather than merely fluctuations in financial data. The late-stage Phase III ESSENCE clinical trials for the two exon-skipping drugs, AMONDYS 45 and VYONDYS 53, failed to achieve statistical significance on the primary endpoints, casting greater uncertainty over future full approval, pricing, and sales. Against a backdrop of already significant safety and regulatory pressures, this triggered a "panic" sell-off in the market Despite setbacks, Sarepta stated that it still plans to meet with officials from the U.S. Food and Drug Administration (FDA) to discuss converting the current accelerated approval of these drugs to full approval.

Duchenne muscular dystrophy typically begins in early childhood and worsens over time, making walking, breathing, and other daily activities increasingly difficult.

Due to the increasing intensity of regulatory scrutiny in recent years, as well as the deaths of three patients related to the company's other gene therapy Elevidys, which previously led to a suspension of the company's clinical trials and raised concerns about the company's safety oversight, Sarepta has lost about 80% of its market value this year, meaning its stock price has also significantly declined