Summit Therapeutics (US:SMMT) Globenewswire·2025-09-16 20:31Core Viewpoint - The Portnoy Law Firm has initiated an investigation into Summit Therapeutics Inc. for potential securities fraud, with plans to file a class action on behalf of investors [1][3]. Group 1: Investigation Details - The investigation focuses on possible violations of federal securities laws related to the company's Phase III clinical trial results for ivonescimab [3]. - On May 30, 2025, Summit announced that patients treated with ivonescimab and chemotherapy were 48% less likely to progress or die compared to those receiving chemotherapy alone, but the drug did not show a statistically significant difference in overall survival [3]. Group 2: Stock Price Impact - Following the announcement of the Phase III trial results, Summit's stock price dropped by $7.99 per share, or 30.5%, closing at $18.22 on May 30, 2025 [4]. - On September 7, 2025, additional data revealed weaker results for ivonescimab in North American and European patients, leading to a further decline of $6.54 per share, or 25.15%, with a closing price of $19.45 on September 8, 2025 [4].