Summit Therapeutics Stock Sparks Retail Buzz After Ivonescimab Combo Cuts Cancer Progression Risk By 40%

Retail buzz around Summit Therapeutics picked up Sunday after the biotech reported what it called a first-of-its-kind result in a major lung cancer study, showing that its experimental antibody ivonescimab, used alongside chemotherapy, outperformed a leading immunotherapy treatment in patients with advanced squamous non-small cell lung cancer (NSCLC).

In the late-stage HARMONi-6 trial from Summit’s partner Akeso, the drug combination of ivonescimab plus chemotherapy helped people with the disease live about 11 months before their cancer worsened, compared with about 7 months for those taking the current standard therapy, tislelizumab plus chemotherapy. 

The results work out to a 40% lower risk of the disease progressing or causing death, a first for this type of lung cancer.

Safety Profile Remains Manageable

The PD-1/VEGF bispecific antibody, ivonescimab, also had a manageable safety profile. Serious side effects and discontinuations of treatment were at similar rates to tislelizumab. Most VEGF-related side effects (for example, mild hypertension or proteinuria) were reversible and did not cause patients to stop treatment.

Maky Zanganeh, Co-CEO and President of Summit, said the results demonstrate how ivonescimab’s novel mechanism may allow for longer treatment duration and stronger clinical benefit compared with other PD-1 and VEGF therapies given separately. “No more striking is this result than in squamous NSCLC, where the benefit of anti-VEGF therapy has been largely unrealized,” she said.

Expanding To Global Studies

Summit is also advancing its HARMONi-3 global Phase III trial, designed to test ivonescimab plus chemotherapy against pembrolizumab (Keytruda) plus chemotherapy in newly diagnosed NSCLC. 

The company has now split the trial into two parts to evaluate results separately for squamous and non-squamous tumors.

The squamous cohort is expected to finish enrollment in the first half of 2026, with data expected later that year, while the non-squamous group should complete enrollment in the second half of 2026.

What’s The Buzz On Stocktwits?

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

Some users were cautious, noting concerns about the lack of overall survival data and warning it could weigh on the stock, saying the update is “necessary by [the] FDA for approval.”

Others struck a more upbeat tone, with one trader expressing excitement for the market open and another calling the press release “very promising.” One user said they expected early volatility, speculating that “smart shorts” could start covering quickly once trading begins.

Summit’s stock has risen 18% so far in 2025.

For updates and corrections, email newsroom[at]stocktwits[dot]com.

Share

·

Add us on