Why Is SUMMIT THERAPEUTICS (SMMT) Stock Up Today?

Why SMMT stock is up today

Summit Therapeutics (SMMT) surged 17.33% to $17.13 in intraday trading on the heels of positive clinical trial results from its partner Akeso. The stock's sharp rise was driven by the release of Phase III HARMONi-2 trial data, which showed that ivonescimab, the company's lead cancer therapy, outperformed pembrolizumab in overall survival for patients with PD-L1-positive advanced non-small cell lung cancer (NSCLC). The results represent a significant milestone for the company and its development pipeline.

Akeso, Summit’s partner, reported that ivonescimab monotherapy demonstrated a statistically significant improvement in survival compared to pembrolizumab monotherapy. The data was announced by Summit on September 2, 2026, and followed by a filing of a Form 8-K on September 3. The positive outcome has generated renewed investor interest in the company’s prospects, especially as it positions ivonescimab as a potential alternative to Merck’s Keytruda in the lung cancer market.

What The Data Shows

The stock has gained 26.4% over the past eight sessions, rising from $13.23 to $16.72. This upward trend continued with today’s 17.33% move, which pushed the stock to $17.13. Summit’s market cap is currently $11.3 billion, though the company remains unprofitable with a trailing twelve-month EPS of -1.12 and a revenue decline of 100.0% TTM. The stock is trading within its 52-week range of $12.07 to $29.23 and hit 26 fresh 52-week highs on September 3. Additionally, two co-CEOs, Robert Duggan and Mahkam Zanganeh, each purchased shares on June 12, 2026, in transactions totaling $100.0 million.

What To Watch

Investors should monitor the November 2026 FDA PDUFA decision for ivonescimab in NSCLC, which has been highlighted as a key catalyst. Continued coverage and data releases from the HARMONi-3 trial will also be important to watch.