On October 19, 2025 Akeso (9926.HK) reported the final analysis results from the COMPASSION-15/AK104-302 study at the 2025 European Society of Medical Oncology (ESMO) (Free ESMO Whitepaper) Congress (ESMO 2025) . COMPASSION-15 is a Phase III clinical trial evaluating cadonilimab, Akeso’s first-in-class PD-1/CTLA-4 bispecific antibody, in combination with oxaliplatin and capecitabine as first-line treatment for unresectable, locally advanced, recurrent, or metastatic gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. Professor Shen Lin, principal investigator from Peking University Cancer Hospital, presented the findings in an oral session at ESMO (Free ESMO Whitepaper) 2025.

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In this final analysis presented at ESMO (Free ESMO Whitepaper) 2025 (median follow-up: 33.9 months), the cadonilimab regimen demonstrated enhanced long-term survival benefits in first-line advanced G/GEJ adenocarcinoma. With the extended follow-up period and more mature data, the cadonilimab treatment regimen showed a further reduction in the risk of death compared to the control group. This consistent benefit was observed across all PD-L1 expression subgroups.

The interim analysis of COMPASSION-15, with a median follow-up of 18.7 months, was previously published in Nature Medicine in January 2025. The data presented at ESMO (Free ESMO Whitepaper) 2025 were analyzed using the same statistical methodology.

COMPASSION-15 2025 ESMO (Free ESMO Whitepaper) Data

In the intent-to-treat (ITT) population:

With long-term follow-up, the cadonilimab regimen demonstrated a significant 39% reduction in the risk of death (OS HR 0.61) versus the control group, showing further improvement over the data from the median 18.7-month follow-up (OS HR 0.66).
With extended follow-up, in the PD-L1 CPS ≥5 population, the cadonilimab regimen demonstrated a significant 51% reduction in the risk of death (OS HR 0.49; p < 0.001) compared to the control group, showing further improvement over the data from the median 18.7-month follow-up (OS HR 0.58).
With long-term follow-up, in the PD-L1 CPS <5 population, the cadonilimab regimen showed a significant 24% reduction in the risk of death (OS HR 0.76; 95% CI: 0.59-0.99; p = 0.019) versus the control group, with a strengthening trend of benefit compared to the data from the median 18.7-month follow-up (OS HR 0.75; 95% CI: 0.56-1.00).
Following extended the follow-up period, the cadonilimab combination regimen maintained a favorable safety profile, with no new safety signals emerging.
In the COMPASSION-15 study, patients with PD-L1 CPS <5 (low expression) and CPS <1 (negative expression) are 49.8% and 23%, respectively, of the ITT population. This represents a higher proportion of PD-L1 low and negative patient population in COMPASSION-15 compared to previous Phase III trials of other immune checkpoint inhibitors used in the treatment of first-line gastric cancer. Previous studies have shown limited responses to PD-1/L1 inhibitors in PD-L1 low-expression or negative patients.

Cadonilimab was approved by the NMPA in September 2024 for the first-line treatment for advanced gastric cancer, offering a new and effective immunotherapy option. Cadonilimab has been included in the 2025 CSCO Gastric Cancer Guidelines as the only Category I recommendation (Level 1A evidence) for first-line immunotherapy, regardless of PD-L1 expression, and is currently widely used in clinical practice.

(Press release, Akeso Biopharma, OCT 19, 2025, View Source [SID1234656792])