Summit Therapeutics Inc. (SMMT) saw its shares plummet by 5.02% in Monday's pre-market trading session. The biopharmaceutical company's stock movement can be attributed to the following key developments:

Summit announced a clinical trial collaboration with Pfizer to evaluate its investigational drug ivonescimab in combination with several of Pfizer's antibody drug conjugates (ADCs) for the treatment of multiple solid tumors. Under the agreement, Summit will provide ivonescimab for the proposed studies, which are expected to begin in mid-2025. Pfizer will be responsible for conducting the operations and associated costs of these trials.

Additionally, Summit reported its financial results for the fourth quarter and full year ended December 31, 2024. The company posted a wider net loss of $221.3 million, or $0.31 per share, for the full year 2024, compared to a net loss of $614.9 million, or $0.99 per share, in the previous year. Research and development expenses increased significantly to $150.8 million in 2024, up from $59.4 million in 2023, reflecting the company's expanded clinical studies and development costs related to ivonescimab.