SMMT Stock Surges Overnight: Cancer Drug Survival Win Raises The Bar As PFE, BMY, MRK Chase Keytruda's Successor

• New ASCO data boosted the case for Ivonescimab as a potential challenger to Merck's blockbuster cancer drug Keytruda.
• Phase 3 Harmoni-6 data showed that Ivonescimab plus chemotherapy extended survival versus the study's control arm.
• Big Pharma is piling into the space, with BMY, PFE and MRK all advancing rival therapies aimed at the same opportunity. 

Shares of Summit Therapeutics (SMMT) surged 13% in overnight trading heading into Monday after new survival data boosted the case for Ivonescimab as a potential challenger to Keytruda, raising the stakes for Pfizer (PFE), Bristol Myers Squibb (BMY) and Merck (MRK), which are all chasing the same next-gen cancer drug opportunity.

Shares of big pharma players were down overnight, with PFE down 0.3%, BMY down 0.5%, and MRK down over 1%. Meanwhile, SMMT snapped two straight weeks of losses, ending last week up 6%.  

Why SMMT's New Data Matters

The new data came from the Phase 3 Harmoni-6 study, presented during ASCO's Plenary Session. In patients with advanced squamous non-small cell lung cancer, Ivonescimab plus chemotherapy helped patients live longer than Tislelizumab plus chemotherapy, extending median overall survival to 27.9 months from 23.7 months. 

Nearly 65% of patients treated with Ivonescimab were still alive after two years, compared with about 49% in the control arm. Benefits were seen regardless of PD-L1 status, a biomarker used to predict how well patients may respond to immunotherapy.

The results help answer one of the biggest questions surrounding Ivonescimab: whether the strong disease-control benefits seen in earlier studies would ultimately translate into patients living longer. Summit said Harmoni-6 is the first Phase 3 study to show a “statistically significant” survival advantage over a PD-1 inhibitor plus chemotherapy regimen in first-line, driver-mutation-negative advanced non-small cell lung cancer.

The findings also come after earlier Phase 3 results from Summit and its Chinese partner Akeso first put Ivonescimab in the spotlight in 2024. In the Harmoni-2 study, the drug outperformed Merck's Keytruda in first-line PD-L1-positive lung cancer, helping fuel investor enthusiasm around a new class of cancer drugs known as PD-(L)1xVEGF therapies. The interest has since spread across the industry, with Pfizer, Bristol Myers Squibb and Merck all advancing competing programs.

Beyond overall survival, patients receiving Ivonescimab went nearly twice as long before their cancer worsened, and tumors shrank more often and for longer periods than in the comparison group.

The Race Beyond Keytruda

Keytruda has become the world's best-selling medicine and the backbone of modern cancer immunotherapy. However, Merck faces a major patent cliff later this decade, with key protections expected to begin expiring in 2028, intensifying the search for the next major immunotherapy drug.

That's where PD-(L)1xVEGF therapies come in. These drugs combine two established anti-cancer approaches in one molecule. One component helps the immune system attack tumors, while the other blocks VEGF, a protein tumors use to create blood vessels that fuel growth.

PFE, BMY And MRK Are Building Rivals

The latest ASCO meeting highlighted how quickly competition is building around this emerging class of cancer drugs. Over the weekend, Bristol Myers Squibb and BioNTech reported Phase 2 data showing that Pumitamig plus chemotherapy shrank tumors in 57.1% of patients with non-squamous lung cancer and 68.4% of those with squamous disease. The companies have already launched multiple late-stage Phase 3 trials.

Pfizer is also advancing its own PD-1xVEGF therapy, PF-08634404, through Phase 3 studies in lung cancer and colorectal cancer. Merck, meanwhile, is developing MK-2010, a similar drug licensed from LaNova Medicines, as it looks beyond Keytruda, its blockbuster cancer treatment that faces a major patent cliff later this decade.

What's Next For SMMT?

While Pfizer, Bristol Myers Squibb and Merck are still advancing competing programs through clinical trials, Summit is already one step closer to the market. The company has an FDA application under review for Ivonescimab plus chemotherapy in EGFR-mutated lung cancer after progression on EGFR-targeted therapy. The filing was accepted in January, with a regulatory decision expected by Nov. 14, making Summit the only company in the group with a therapy currently under FDA review. 

Beyond lung cancer, Summit recently reported a 70.8% objective response rate in a Phase 2 colorectal cancer study, while the global Phase 3 Harmoni-GI3 trial continues enrollment. Investors are also closely watching Harmoni-3, a global Phase 3 study comparing Ivonescimab plus chemotherapy directly against Keytruda plus chemotherapy in over 1,000 patients with first-line non-small cell lung cancer.

How Do Retail Traders Feel About SMMT?

On Stocktwits, retail sentiment for SMMT surged to an all-time high, reaching an ‘extremely bullish’ reading of 97/100, reversing from ‘bearish’ territory just a week ago as message volume jumped by over 9,200% over the same period. The ticker’s watcher base has also climbed 2% in a week.

One user said, “It also looks like Ivonescimab will be the standard of care across many types of cancer in the future. Hard to measure the overall impact on SMMT stock but lets just say I wouldn't want to be short.”

Another user noted, “The problem is regulatory, since this was an Akeso sponsored trial, great for a label add to Ivon already approved in China, but FDA will question China trials. They will see it as excellent supportive data, but not sufficient as a sole single trial for US full approval unless of course they suddenly are progressive in their approach.”

SMMT stock has declined 33% over the past year. 

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