Ivonescimab reduced the risk of death by 34% in squamous NSCLC | ASCO 2026

A bispecific antibody that is already approved in China but in phase 3 development in the United States reduced the risk of death by 34% in patients with advanced squamous non-small cell lung cancer (NSCLC). Additionally, ivonescimab plus chemotherapy increased overall survival regardless of PD-L1 protein levels compared with Tevimbra (tislelizumab) plus chemotherapy, according to results presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, taking place May 29 to June 2 in Chicago and published simultaneously in The Lancet.

Lung cancer is the second most common cancer in the United States. The American Cancer Society estimates that there will be 229,410 new cases of lung cancer this year, and there will be about 124,990 deaths from lung cancer. Squamous non-small cell lung cancer makes up about 25% of cases of lung cancer and is a difficult cancer to treat. The typical treatment for squamous NSCLC is chemotherapy plus a checkpoint inhibitor, such as Tevimbra.

“Squamous non-small cell lung cancer is associated with worse clinical outcomes than non-squamous non-small cell lung cancer. This is one of very few studies in advanced squamous non-small cell lung cancer that has shown median survival beyond two years,” lead study author Shun Lu, MD, PhD, Shanghai Chest Hospital, Jiao Tong University School of Medicine, Shanghai, China, said in a news release.

“There’s been a largely unmet medical need in squamous lung cancer,” David Spigel, M.D., president and chief medical officer at Sarah Cannon Research Institute, said during a press briefing during the meeting. “Although we’ve had advanced immunotherapy, this group still often has a very poor prognosis, even with advanced therapies like chemotherapy and immunotherapy.”

Ivonescimab is a first-in-class bispecific monoclonal antibody that helps the immune system recognize and attack cancer cells by addressing two different targets. It is able to block the protein PD-1 that cancer uses to hide from the immune system. It is also able to block VEGF, a protein that triggers new blood vessel formation.

Ivonescimab was developed by the Chinese company Akeso Biopharma and is available in China. Akeso has partnered with Summit Therapeutics for development and commercialization in the United States.

The phase 3 HARMONi-6 study was designed to compare ivonescimab and chemotherapy with Tevimbra for first-line treatment in advanced squamous NSCLC. The trial included 532 people in China with advanced squamous NSCLC. Of these, 266 received ivonescimab and the chemotherapies paclitaxel and carboplatin. The 266 people in the control group received Tevimbra and the same chemotherapies.

Earlier results from the trial showed that ivonescimab improved progression-free survival by about 11 months compared with 9 months for Tevimbra. Researchers wanted to determine if progression-free survival was an indicator of overall survival.

They found that after a median follow-up of 21.4 months, the median overall survival after ivonescimab and chemotherapy treatment was about 28 months, compared with 24 months with Tevimbra and chemotherapy. Adverse events were similar in both groups. Bleeding occurred in about 3% of the ivonescimab group and about 1% of the Tevimbra group.

“We’ve been waiting for overall survival data, albeit a secondary endpoint [in the HARMONi-6 study]," Spigel said. “This is a first randomized, controlled trial, albeit in a region of the world that is limited in its geography in a Chinese population. It's hard to know how this applies to a population of patients beyond that. There are differences in ethnicity that affect how drugs like this work. We wait on other studies like the HARMONi-3 study.”

HARMONi-3 is a phase 3 trial sponsored by Summit Therapeutics that is looking at the effects of ivonescimab in people with NSCLC in populations worldwide, including the United States, Europe, and Asia. This trial will enroll 1,600 patients in two cohorts (squamous and non-squamous) and compare ivonescimab and chemotherapy with Keytruda (pembrolizumab) and chemotherapy.

Additionally, Summit Therapeutics has submitted a biologic license application for ivonescimab in patients with epidermal growth factor receptor (EGFR)-mutated locally advanced or metastatic non-squamous NSCLC after treatment with tyrosine kinase inhibitor (TKI) therapy. The Prescription Drug User Fee Act (PDUFA) goal date is Nov. 14, 2026. This application is based on the HARMONi trial.

Summit Therapeutics and Akeso are also studying ivonescimab plus chemotherapy as a treatment for first-line metastatic colorectal cancer in patients with unresectable microsatellite stable (MSS) disease. Data from an open-label phase 2 study was also presented at ASCO. This study found that the overall study population achieved an objective response rate (ORR) of 70.8%.