Summit Therapeutics Inc. (SMMT) is having a good Thursday. Its development partner, Akeso Inc., just dropped some very encouraging data from a late-stage trial, and investors are clearly liking what they see.
The news comes from the Phase 3 HARMONi-2 study, which pitted ivonescimab as a standalone treatment against Merck & Co. Inc.'s (MRK) blockbuster immunotherapy Keytruda (pembrolizumab). The target: locally advanced or metastatic non-small cell lung cancer (NSCLC) with positive PD-L1 expression.
In a preplanned interim analysis, Akeso reported that ivonescimab monotherapy delivered a statistically significant improvement in overall survival compared to pembrolizumab. Overall survival was a key secondary endpoint in the study, and hitting it is a big deal. The company plans to present the full findings at an upcoming medical conference.
This isn't the first time ivonescimab has shown promise against Keytruda. The HARMONi-2 study is being conducted exclusively in China, with Akeso handling all the data generation and analysis. Back in the primary analysis, the Independent Radiologic Review Committee found that ivonescimab significantly improved progression-free survival compared to Keytruda, with a hazard ratio of 0.51. That's a strong result, and the benefit was seen across various patient subgroups, including those with high and low PD-L1 expression, as well as squamous and non-squamous tumor types.
These earlier results were enough to get ivonescimab approved in China. In April 2025, the country's National Medical Products Administration granted marketing authorization for the drug, and it's now commercially available there for NSCLC indications.
But the regulatory picture is different elsewhere. In Summit Therapeutics' licensed territories, which include the U.S., ivonescimab is still strictly investigational. That means there's a long road ahead before it could potentially challenge Keytruda on a global scale. Still, the data so far is certainly turning heads.
Investors reacted swiftly. Summit Therapeutics shares were up 10.79% at $15.55 at the time of publication on Thursday, according to market data.
While it's still early days, the HARMONi-2 results add to the growing evidence that ivonescimab could be a serious contender in the lung cancer space. For now, all eyes will be on the upcoming medical conference where the full overall survival data will be unveiled.
