New PD-1/VEGF Drug Shows Promise, But Survival Benefit Uncertain

Akeso and Summit Therapeutics' dual-acting cancer drug ivonescimab has demonstrated potential in improving survival rates compared to Merck & Co.'s Keytruda in a recent clinical trial. However, the results have sparked debate among industry experts due to the lack of statistical significance in the survival benefit.

Ivonescimab's Performance Against Keytruda

Interim results from a Phase 3 trial in China revealed that ivonescimab, a PD-1/VEGF inhibitor, reduced the risk of death by 22% compared to Keytruda in patients with non-small cell lung cancer. While this reduction is considered clinically meaningful by some, the difference did not reach statistical significance, leading to mixed reactions from investors and analysts.

The drug had previously shown promise by cutting the risk of disease progression in half versus Keytruda, which led to its first regulatory approval in China on April 28, 2025. This earlier success had sparked increased investment in PD-1/VEGF inhibitors across the pharmaceutical industry.

Market Response and Expert Analysis

Following the release of the interim survival data, shares of both Akeso and Summit Therapeutics experienced significant declines. Summit's stock price plummeted by more than one-third, while Akeso saw a double-digit percentage drop.

Analysts have expressed varying opinions on the results. Eric Schmidt of Cantor Fitzgerald described the outcome as "solid, not spectacular," noting that investors had hoped for at least a 24% reduction in death risk. Leerink Partners' Daina Graybosch suggested that while it was unrealistic to expect statistical significance at this early stage, the reported survival benefit was still "modest."

Future Outlook and Ongoing Studies

The debate surrounding ivonescimab's efficacy is expected to continue as more data becomes available. A final analysis of the survival results is anticipated later this year, which may provide more definitive conclusions about the drug's potential.

Additionally, a direct comparison between ivonescimab and the current standard of care is underway in the Harmoni-3 trial. This study is evaluating ivonescimab combined with chemotherapy against the Keytruda-chemo combination in lung cancer patients, with results expected in 2027.

As the pharmaceutical industry closely watches the development of PD-1/VEGF inhibitors, the coming months and years will be crucial in determining whether these drugs can truly surpass the efficacy of established immunotherapies like Keytruda in the treatment of various cancers.