Shares of Summit Therapeutics (SMMT -9.90%) were sinking 22.6% as of 11:10 a.m. ET on Tuesday. This sell-off follows a similar steep decline of 22% on Friday after Summit revealed late-stage data for its lead candidate, ivonescimab, in combination with chemotherapy in treating non-small cell lung cancer (NSCLC).
In a regulatory filing on Friday, Summit referenced top-line data included in a presentation by its Chinese partner, Akeso, at the 2024 American Society of Clinical Oncology (ASCO) annual meeting. Patients receiving ivonescimab in combination with chemotherapy had a median progression-free survival of 7.06 months compared to 4.8 months for patients receiving only chemotherapy. However, 61.5% of patients receiving the combo experienced severe or medically significant treatment-emergent adverse events.
Some good news for Summit Therapeutics
Investors reacted negatively to the late-stage data for ivonescimab. However, there was some good news: China's National Medical Products Administration gave the drug its first regulatory approval on Friday as a second-line treatment for patients with epidermal growth factor receptor (EFGR) mutated, advanced or metastatic NSCLC.
Was there any silver lining in the safety data presented by Akeso? Perhaps: Summit noted that the most common serious adverse events were related to chemotherapy rather than ivonescimab.
Is Summit Therapeutics stock a buy on the pullback?
Some aggressive investors could view Summit Therapeutics' pullback as a buying opportunity. However, I think that most investors will be better off staying on the sidelines with this clinical-stage biotech stock. Other stocks offer more attractive risk-reward propositions, in my view.
