Summit Therapeutics’ partner Akeso is set to present overall survival data for their PD-1/VEGF asset ivonescimab at the American Society of Clinical Oncology (ASCO) meeting this weekend. The results are expected to provide insights into how this emerging therapy may compete with established anti-PD-(L)1 agents such as Merck’s Keytruda in lung cancer, according to a note from BMO Capital Markets on May 29.
The plenary session, scheduled for Sunday, will feature updated findings from the Phase 3 HARMONi-6 study involving patients with first-line advanced squamous non-small cell lung cancer. Previously released progression-free survival data showed that ivonescimab achieved 11.14 months compared to 6.9 months in the comparator group. The new ASCO update will focus on overall survival and compare ivonescimab against BeOne’s Tevimbra and chemotherapy.
BMO Capital Markets said it expects the HARMONi-6 trial to show statistically significant improved survival, estimating a hazard ratio between 0.65 and 0.72 in its most optimistic scenario. “While HARMONi-6 won’t dethrone King Keytruda, positive data could start to change the narrative around IO [immuno-oncology] in NSCLC,” BMO wrote.
PD-(L)1/VEGF therapies target two cancer pathways by blocking checkpoint inhibition and preventing tumor blood vessel formation—a mechanism different from classic immuno-oncology agents like Keytruda. Several companies have developed similar assets; Merck has MK-2010 in development but has not announced Phase 3 plans or prioritized it over other projects such as sacituzumab tirumotecan (sac-TMT), an antibody-drug conjugate acquired through partnerships with Daiichi Sankyo and Kelun-Biotech.
Other competitors include BioNTech, which partnered with Bristol Myers Squibb in June 2025 on pumitamig under an $11 billion deal; their therapy’s Phase 2/3 ROSETTA Lung-02 results will also be showcased at ASCO. Summit Therapeutics is ahead of these rivals, having already submitted an FDA application for ivonescimab as a later line treatment in non-small cell lung cancer, while Pfizer and AbbVie are advancing similar bispecific drugs through clinical development.
Analysts predict that PD-(L)1/VEGF bispecifics could see broader use beyond lung cancer—potentially offering benefits where angiogenesis and immune escape play key roles—and emphasize that strong efficacy will be necessary once Keytruda loses patent exclusivity in 2029. “Bispecifics need to demonstrate significantly differentiated efficacy to succeed in a post-Keytruda market, as incrementally improved efficacy could limit uptake,” BMO wrote.
