Retail Traders Flock To Summit Therapeutics After New Cancer Drug Data Shows Survival Gains

Retail traders turned their attention to Summit Therapeutics late Sunday after the company released new follow-up data from its Phase III HARMONi trial. The study is testing ivonescimab, an experimental cancer drug, together with chemotherapy in patients with advanced non-small cell lung cancer.

The trial focused on people whose tumors carried Estimated Glomerular Filtration Rate (EGFR) mutations and who had already failed a third-generation EGFR therapy. In this group, past attempts with PD-1 drugs had not delivered survival gains.

In fresh results presented at the World Conference on Lung Cancer in Barcelona, patients on ivonescimab plus chemotherapy lived longer on average than those on chemotherapy alone. 

The overall survival hazard ratio was 0.78, indicating an improvement from the earlier analysis. Median survival was 16.8 months with the drug compared to 14.0 months with chemotherapy.

Among Western patients, the median overall survival was 17 months with ivonescimab versus 14 months for the placebo. In North America specifically, median overall survival had not yet been reached in the ivonescimab arm compared with 14 months on chemotherapy alone. 

Median survival in Asian patients was 16.7 months for ivonescimab versus 14 months for chemotherapy.

The primary analysis, conducted in April, had shown a positive trend in overall survival but did not meet statistical significance. The company noted that the median follow-up for Western patients was shorter than their median overall survival at that time.

Earlier results had already demonstrated that the trial met its main goal. Patients on ivonescimab plus chemotherapy were 48% less likely to see their cancer worsen or to die compared with those on chemotherapy alone.

The treatment also produced better responses: 45% of patients saw their tumors shrink versus 34% on chemotherapy, and those responses lasted longer, with a median of 7.6 months compared with 4.2 months.

Safety data showed the combination was generally manageable and consistent with prior studies. 

Grade 3 or higher treatment-related adverse events occurred in 50% of ivonescimab patients versus 42.2% in the chemotherapy arm. Discontinuations due to adverse events were 7.3% versus 5%, and treatment-related deaths were reported in 1.8% and 2.3% of patients, respectively. The most common events were anemia and reduced blood counts, with less than 1% of ivonescimab patients experiencing severe hemorrhage.

Ivonescimab, also known as SMT112 outside China, is a first-in-class bispecific antibody targeting both PD-1 and Vascular Endothelial Growth Factor (VEGF). 

It was engineered by China’s Akeso and has been tested in more than 2,800 patients globally. The drug is already approved in China and has a U.S. FDA Fast Track designation in the HARMONi trial setting.

On Stocktwits, retail sentiment for Summit was ‘extremely bullish’ amid ‘extremely high’ message volume.

One retail user said that long-term investors in Summit had grown used to the stock falling even on positive news, but pointed out shares are still up nearly 700% over the past five years.

Another user noted that while the day had been volatile, “the markets don’t lie” and suggested Summit CEO Robert Duggan might have more to reveal, adding that he has a reputation for frustrating short sellers. The user speculated the stock could hit $30 by the end of the day.

Summit’s stock has risen 45.6% so far in 2025.

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