Summit Therapeutics Plunges 17.24% on Mixed Trial Data

On September 8, 2025, Summit Therapeutics experienced a significant drop of 17.24% in pre-market trading, reflecting a notable shift in investor sentiment towards the biopharmaceutical company.

Summit Therapeutics recently announced data from the Phase III HARMONi trial, which featured the novel, potential first-in-class investigational bispecific antibody, Ivonescimab. This trial is a critical milestone for the company, as it aims to combine immunotherapy and anti-angiogenesis effects into a single molecule for the treatment of non-small cell lung cancer (NSCLC).

Analysts have shown mixed reactions to Summit Therapeutics' recent developments. Guggenheim initiated coverage on the company with a Buy rating and a $40 price target, while Piper Sandler initiated coverage with a Neutral rating and a $21 price target. UBS also initiated coverage with a Buy rating and a $30 price target, while Leerink Partners initiated coverage with an Underperform rating and a $12 price target. These varying opinions highlight the uncertainty surrounding the company's future prospects.

Summit Therapeutics' financial performance has also been a topic of discussion. The company reported a widening adjusted loss for the second quarter, which may have contributed to the recent stock price decline. Additionally, the company is set to discuss full presentation data from the HARMONi trial at the World Conference on Lung Cancer (WCLC) 2025, which could provide further insights into the potential of Ivonescimab.