Shares in Jade Biosciences slid sharply on Wednesday, losing 9% in morning trading after the US Food and Drug Administration (FDA) issued a complete response letter rejecting the company's marketing application for its lead experimental therapy. The stock was trading at 412p, down from yesterday's close of 453p, marking its biggest single-day decline in six months.
The FDA's decision, announced after US markets closed on Tuesday, cited insufficient clinical data on the drug's long-term safety profile. Jade Biosciences, which focuses on rare disease treatments, had pinned its near-term growth hopes on the candidate, which was expected to generate significant revenue by 2026. The company said in a statement it would 'work closely with the FDA to address the outstanding questions' and expects to resubmit the application within 12 months.
The news weighed on the broader biotech sector. The FTSE 350 Pharmaceuticals & Biotechnology index fell 1.2% to 14,678 points, dragged lower by Jade and a handful of smaller drug developers with similar regulatory exposures. Analysts at Shore Capital noted that the rejection 'removes a key near-term catalyst' for the stock and could force the company to seek additional financing or partnership deals to bridge the gap until resubmission.
For UK-based investors and pension holders with exposure to biotech funds or AIM-listed healthcare stocks, the move serves as a reminder of the binary risk inherent in drug development. Jade Biosciences is listed on the London Stock Exchange's main market, and several large UK fund managers hold positions in the company. The FTSE 100 edged 0.3% lower to 8,215 points, while the FTSE 250 fell 0.5% to 20,430 points, with Jade among the worst performers on the mid-cap index.
Market observers cautioned against panic selling, noting that the company's pipeline includes two other early-stage programmes that are not affected by the FDA decision. However, Jefferies analysts downgraded the stock from 'buy' to 'hold' and cut their price target from 620p to 480p, citing increased uncertainty over the timeline to commercialisation. The stock remains down 22% year-to-date.