Summit's Ivonescimab Shows Promise in Lung Cancer, but FDA Hurdles Remain

Summit Therapeutics and its Chinese partner Akeso have reported mixed results from a Phase 3 trial of their dual-acting cancer drug ivonescimab, potentially complicating the path to U.S. approval. The study, which evaluated ivonescimab in combination with chemotherapy for non-small cell lung cancer (NSCLC) patients with EGFR mutations, demonstrated a significant reduction in tumor progression risk but fell short on survival benefit.

Promising Efficacy in Tumor Progression

The Phase 3 trial results showed that ivonescimab, when administered alongside chemotherapy, reduced the risk of death or disease progression by 48% compared to chemotherapy alone. This outcome aligns closely with previous data from a China-based study, suggesting consistency in the drug's performance across different patient populations.

Summit's chairman and co-CEO Robert Duggan emphasized the potential global impact of these findings, stating that the data "demonstrates the potential benefit ivonescimab has to bring to patients around the world, including the United States."

Survival Benefit: A Critical Hurdle

Despite the positive results in tumor progression, ivonescimab failed to demonstrate a statistically significant improvement in overall survival. The drug showed a 21% reduction in death risk, which did not meet the threshold for statistical significance. This shortfall presents a significant challenge for Summit, as the FDA has indicated that a survival benefit is "necessary" to support a submission for approval.

The company noted that the follow-up time for "western" patients in the trial was less than the median overall survival figure at the time of data analysis, suggesting that survival outcomes could potentially improve with longer follow-up.

Implications for FDA Approval and Market Position

Summit's path to FDA approval now faces uncertainty due to the lack of clear survival benefit. The company acknowledged that the FDA's stance on survival data "will weigh into Summit's considerations" regarding the timing of a potential submission.

Ivonescimab is at the forefront of a new class of cancer drugs that simultaneously target PD-1 and VEGF proteins. Its performance is being closely watched by scientists and investors alike, as it could have broad implications for cancer research and treatment strategies.

While the drug has shown promising results in China-based studies, including outperforming Merck's Keytruda in progression-free survival, it has yet to demonstrate superiority over the standard Keytruda-chemotherapy regimen in the types of multi-country trials preferred by the FDA.

An ongoing study comparing ivonescimab plus chemotherapy against Keytruda plus chemotherapy in NSCLC is expected to report results in 2027, potentially providing more definitive data on the drug's efficacy relative to current standard-of-care treatments.