Ivonescimab, an experimental lung cancer treatment developed by Akeso and Summit Therapeutics (SMMT), demonstrated a 34% reduction in death risk during a China Phase 3 study, according to data unveiled at ASCO on Sunday.
This survival advantage could establish the bispecific antibody as a serious competitor to Merck’s leading cancer therapy Keytruda, which delivered more than $30 billion in revenue last year.
Key Takeaways
- Ivonescimab extended median survival by four months versus standard care
- Drug targets both PD-1 and VEGF pathways simultaneously
- Global Phase 3 results expected in second half 2026
Market Context and Trial Results
The Harmoni-6 study included patients with squamous non-small cell lung cancer in China, evaluating ivonescimab combined with chemotherapy against conventional immunotherapy regimens 1. Subjects treated with the experimental therapy achieved a median survival of 27.9 months compared to 23.7 months in the control arm.
Summit Therapeutics stock has climbed approximately 600% over the past two years following initial promising data, although shares have dropped recently due to questions about global effectiveness 1. The firm obtained licensing rights to ivonescimab outside China from Chinese biotech company Akeso.
Clinical Significance and Expert Views
The bispecific antibody concurrently targets PD-1 and VEGF pathways, replicating the combined effects of Merck’s Keytruda with Roche’s Avastin within a single molecule 1. Earlier research demonstrated the treatment’s ability to control tumors effectively, but overall survival outcomes were required for potential FDA approval consideration.
“The fact that it shows an improvement in overall survival in a difficult-to-treat patient population is very encouraging,” said Dr. Suresh Ramalingam, executive director of the Winship Cancer Institute of Emory University 1. However, he noted the China-only trial raises questions about applicability to broader patient populations.
Safety Profile and Market Competition
Bleeding complications occurred in nearly 25% of patients receiving ivonescimab, double the rate seen with standard treatment, though severe cases remained below 3% 1. The safety profile was described as comparable to existing therapies by investigators.
The drug faces competition from other emerging therapies, including antibody-drug conjugates also being presented at the ASCO meeting. A separate study showed Merck’s partnership with Kelun-Biotech reduced tumor progression risk by 65% in Chinese lung cancer patients 2.
Industry Outlook and Future Development
PD-1/VEGF combination drugs represent a hotly debated new class of cancer medicines, with licensing deals reaching $30 billion last year 1. While some view these agents as potential successors to current blockbusters, others remain skeptical about broad clinical impact.
Summit plans to report progression-free survival data from its global Harmoni-3 trial in the second half of this year, with results from non-squamous patients expected in early 2027. These results will be crucial for determining the drug’s commercial potential outside China.
Not investment advice. For informational purposes only.
References
1Angelica Peebles (2026-05-31). “A hotly debated lung cancer drug cut the risk of death by 34% in a late-stage trial in China”. CNBC. Retrieved May 31, 2026.
2Adam Feuerstein (2026-05-21). “Merck-Kelun lung cancer drug cut risk of tumor progression by 65%, ASCO abstract shows”. STAT News. Retrieved May 31, 2026.