Summit Therapeutics (SMMT): Why Shares Jumped 21.50% on Breakthrough Phase 3 Results

Summit Therapeutics (SMMT) has captured the market’s attention with a dramatic 21.50% surge, closing at $33.23 on April 23, 2025. This remarkable move is rooted in a pivotal development: the company’s partner, Akeso, announced that their Phase 3 HARMONi-6 trial of ivonescimab in combination with chemotherapy achieved a statistically significant and clinically meaningful improvement in progression-free survival (PFS) for patients with locally advanced or metastatic squamous non-small cell lung cancer (NSCLC), regardless of PD-L1 expression. This news has sent a wave of optimism through the biotech sector and positioned Summit Therapeutics as a company to watch in oncology innovation.

Breakthrough Results in the HARMONi-6 Phase 3 Trial

The HARMONi-6 trial, conducted by Akeso in China, compared ivonescimab plus platinum-based chemotherapy to tislelizumab (an anti-PD-1 antibody) plus the same chemotherapy regimen. The trial met its primary endpoint, with ivonescimab demonstrating a statistically significant and clinically meaningful improvement in progression-free survival. Notably, the benefit was observed in both PD-L1-positive and PD-L1-negative tumor populations, underscoring the broad potential of this therapy.

What sets this result apart is its historical context. According to the press-release, this is the first known Phase 3 trial in NSCLC to show a statistically significant improvement over PD-(L)1 inhibitor therapy combined with chemotherapy in a head-to-head setting. No new safety signals were identified, further supporting the potential of ivonescimab as a next-generation immuno-oncology agent.

Why the Market Reacted So Strongly

Investors are always searching for transformative therapies that can disrupt established standards of care. The positive HARMONi-6 data positions ivonescimab as a credible challenger to current market leaders in first-line NSCLC treatment. The fact that the trial succeeded in a direct comparison against a leading PD-1 inhibitor, and did so across all PD-L1 expression levels, is a major milestone. This suggests ivonescimab could address a broader patient population than many current therapies.

Additionally, the absence of new safety concerns in the trial adds to investor confidence. Safety profiles are critical in oncology, where adverse events can limit a drug’s market potential. The clean safety data, combined with robust efficacy, creates a compelling value proposition for Summit Therapeutics and its shareholders.

Momentum Builds Around Ivonescimab

The excitement around Summit Therapeutics and SMMT is not limited to a single trial. The company has been steadily advancing ivonescimab through multiple late-stage studies. In September 2024, Summit released data from the HARMONi-2 trial, where ivonescimab monotherapy also achieved a statistically significant improvement in progression-free survival compared to pembrolizumab monotherapy, with a hazard ratio of 0.51. This consistent outperformance against established therapies is fueling speculation that ivonescimab could become a new standard in lung cancer care.

Further, Summit is currently enrolling patients in the HARMONi-3 Phase 3 study. This trial, sponsored by Summit, is evaluating ivonescimab combined with chemotherapy versus Merck’s Keytruda (pembrolizumab) plus chemotherapy in first-line metastatic, squamous, and non-squamous NSCLC. The company’s ability to design and execute global trials, and to partner with leading pharmaceutical companies, demonstrates its strategic vision and operational strength.

Strategic Partnerships Amplify Potential

Summit Therapeutics’ collaborative approach is another reason for investor enthusiasm. In February, the company announced a clinical trial collaboration with Pfizer to evaluate ivonescimab in combination with several of Pfizer’s antibody-drug conjugates (ADCs) across multiple solid tumor settings. Under the agreement, Summit will supply ivonescimab, while Pfizer will conduct the studies’ operations. Both companies retain their rights to their respective products, and the studies are expected to begin in the middle of this year. This partnership with a global pharmaceutical leader like Pfizer adds significant credibility to Summit’s pipeline and opens doors to new indications and markets.

Analyst Sentiment and Market Recognition

The market’s positive reaction to the HARMONi-6 results is echoed by Wall Street analysts. Cantor Fitzgerald recently reiterated its Overweight rating on Summit Therapeutics, reflecting continued confidence in the company’s prospects. The stock’s inclusion among the top performers for the week, as highlighted in recent market roundups, further signals growing recognition of Summit’s momentum and the potential impact of its clinical programs.

Investors are taking note of the company’s ability to consistently deliver positive clinical data and secure high-profile partnerships. This combination of scientific achievement and business acumen is rare in the biotech sector and positions Summit as a potential leader in the next wave of oncology innovation.

What’s Next for Summit Therapeutics?

Looking ahead, the full data set from the HARMONi-6 trial will be presented at a major medical conference later this year. This presentation will provide deeper insights into the efficacy and safety of ivonescimab, potentially attracting further interest from the medical community, investors, and potential partners.

Meanwhile, enrollment continues in the HARMONi-3 trial, which could further validate ivonescimab’s efficacy in a global setting and against another industry-leading therapy. The collaboration with Pfizer is also set to begin, expanding the scope of ivonescimab’s development into additional solid tumor types. These upcoming milestones offer multiple catalysts for continued investor interest and potential stock appreciation.

Big Picture: The Oncology Market Opportunity

Lung cancer remains one of the most challenging and deadly cancers worldwide. The market for innovative therapies in NSCLC is vast, with billions of dollars in annual sales at stake. Current standard-of-care treatments, such as PD-1 and PD-L1 inhibitors, have improved outcomes but leave significant unmet needs, especially for patients who do not respond to existing immunotherapies.

Ivonescimab’s ability to demonstrate superiority over established PD-1 inhibitors, regardless of PD-L1 status, could redefine treatment paradigms. If future data continue to support its efficacy and safety, ivonescimab could capture significant market share and become a cornerstone therapy in lung cancer and potentially other solid tumors.

Investor Takeaways: Why SMMT Deserves Attention

The 21.50% jump in SMMT shares is not just a reaction to a single press release—it reflects a growing consensus that Summit Therapeutics is on the cusp of something transformative. The company’s lead asset, ivonescimab, has now delivered positive results in multiple Phase 3 trials, outperforming some of the most widely used immunotherapies in lung cancer. Strategic partnerships with industry giants like Pfizer further validate the science and expand the commercial potential.

With additional data presentations and trial readouts on the horizon, Summit Therapeutics is well-positioned for continued momentum. For investors seeking exposure to breakthrough oncology innovation, SMMT offers a compelling story of scientific progress, strategic execution, and the potential for significant value creation.

Conclusion: SMMT’s Surge Signals a New Era in Cancer Therapy

Summit Therapeutics’ 21.50% stock surge is a testament to the power of clinical innovation and strategic vision. As ivonescimab continues to deliver unprecedented results in head-to-head trials, the company is rapidly emerging as a force in the fight against lung cancer. With more data on the way and partnerships expanding its reach, Summit Therapeutics and SMMT are firmly in the spotlight for investors looking to participate in the next generation of cancer breakthroughs.