Summit Therapeutics Inc. (NASDAQ:SMMT) saw its stock decline by 3.5% today after releasing topline results from its Phase III HARMONi clinical trial. The study examined the effectiveness of ivonescimab when combined with chemotherapy in treating patients with EGFR-mutated non-small cell lung cancer who had progressed after prior treatment with third-generation EGFR tyrosine kinase inhibitors.
The trial met its primary endpoint, demonstrating a statistically significant improvement in progression-free survival (PFS), with a hazard ratio of 0.52 — translating to a 48% reduction in the risk of disease progression or death compared to chemotherapy alone. However, the overall survival (OS) data, another key measure, did not achieve statistical significance, showing a hazard ratio of 0.79.
While the PFS results are encouraging, the lack of a confirmed OS benefit could pose a challenge for regulatory approval. Summit stated that it plans to pursue a Biologics License Application (BLA) for ivonescimab but acknowledged that the FDA has emphasized the importance of a significant OS improvement for approval.
Despite the stock dip, Truist Securities analyst Asthika Goonewardene expressed cautious optimism. He noted that the trial’s results, particularly the similarities in outcomes between Eastern and Western patient populations, suggest potential for broader regulatory acceptance. He remarked that the data from China may be sufficiently consistent to support applications in both the U.S. and Europe.