Summit Therapeutics stock dips after clinical trial results

Investing.com -- Shares of Summit Therapeutics Inc. (NASDAQ:SMMT) traded down 3.5% today as the company released topline results from its Phase III HARMONi clinical trial. The study evaluated the efficacy of ivonescimab in combination with chemotherapy for patients with EGFR-mutated non-small cell lung cancer who had progressed after treatment with a third-generation EGFR tyrosine kinase inhibitor.

Despite demonstrating a statistically significant improvement in progression-free survival (PFS) with a hazard ratio of 0.52, the overall survival (OS) trend did not reach statistical significance, showing a hazard ratio of 0.79. The trial’s primary endpoint was met for PFS, but the OS benefit, a key factor for marketing authorization by the FDA, remains unconfirmed at this time.

The mixed results showed that ivonescimab plus chemotherapy reduced the risk of disease progression or death by 48% compared to chemotherapy alone. Summit Therapeutics announced its intention to file a Biologics License Application (BLA) based on these findings but will consider the timing of this filing, as the FDA has indicated that a statistically significant OS benefit is necessary for approval.

Truist analyst Asthika Goonewardene provided a positive outlook on the trial’s implications, stating, "This is good, and the East vs West populations looks similar enough for us to remain optimistic that the data generated for Ivonescimab in China will be reproducible in Western populations." The analyst highlighted the alignment between the Eastern and Western patient data and suggested that the results could be sufficient for seeking US and EU approval.

The safety profile of ivonescimab in combination with chemotherapy was deemed acceptable, with no new safety signals observed. The study reported Grade 3 or higher treatment-emergent adverse events (TEAEs) for 56.9% of patients in the ivonescimab plus chemotherapy arm versus 50.0% with chemotherapy alone.

Summit’s leadership expressed confidence in ivonescimab’s potential to benefit patients globally, including in the United States. The company plans to present more complete data from the clinical study at a future major medical conference and continues to follow patients for long-term outcomes.

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