Summit Therapeutics (US:SMMT) Globenewswire·2025-09-10 04:43Core Viewpoint - The Portnoy Law Firm has initiated an investigation into Summit Therapeutics Inc. for potential securities fraud, following significant stock price declines related to clinical trial results [2][4]. Group 1: Investigation Details - The investigation is focused on possible violations of federal securities laws concerning Summit Therapeutics [4]. - A class action may be filed on behalf of investors affected by the alleged fraud [2]. Group 2: Clinical Trial Results - On May 30, 2025, Summit announced topline results from the Phase III clinical trial of ivonescimab, which showed that patients treated with ivonescimab and chemotherapy were 48% less likely to progress or die compared to those receiving chemotherapy alone [4]. - Despite the initial results, the drug did not demonstrate a statistically significant difference in overall survival, leading to a stock price drop of $7.99 per share, or 30.5%, closing at $18.22 on the same day [4]. - On September 7, 2025, additional data revealed weaker results for ivonescimab in North American and European patients, causing a further decline of $6.54 per share, or 25.15%, to close at $19.45 on September 8, 2025 [4].