Phase II Data of Cadonilimab Regimen as Neoadjuvant Therapy for Resectable Gastric Cancer Presented at ESMO Asia 2025

HONG KONG, Dec. 9, 2025 /PRNewswire/ -- Akeso, Inc. (9926.HK) ("Akeso" or the "Company") announced that data from the Phase II study (COMPASSION-25) for its first-in-class PD-1/CTLA-4 bispecific antibody, cadonilimab, in combination with SOX regimen (oxaliplatin + tegafur/gimeracil/oteracil) as neoadjuvant therapy for resectable gastric or gastroesophageal junction (G/GEJ) adenocarcinoma, was presented at the 2025 ESMO Asia Congress.

Currently, Akeso is running the pivotal Phase III study (AK104-310/COMPASSION-33) investigating cadonilimab combined with the SOX regimen for perioperative treatment of resectable G/GEJ adenocarcinoma. This regimen is expected to further push the efficacy boundaries beyond existing single-target immunotherapies and establish a new standard for perioperative immunotherapy in gastric cancer.

Promising Pathologic Complete Response (pCR) Rate

Among all evaluable patients, the overall pCR rate was 28.6%. Notably, in patients receiving the cadonilimab Q3W dosing regimen, the pCR rate reached 50.0%. pCR, defined as the absence of viable tumor cells in both the primary tumor site and regional lymph nodes upon surgical resection, is considered the "gold standard" surrogate endpoint for evaluating neoadjuvant treatment efficacy and predicting long-term survival benefits.

High Rate of Major Pathologic Response (MPR)

The overall MPR rate (defined as ≤10% residual viable tumor cells) across all evaluable patients was 71.4%. For the cadonilimab Q3W regimen, the MPR rate was as high as 85.7%. This suggests that the cadonilimab-based regimen induces substantial tumor regression in the majority of patients.

100% R0 Resection Rate

All patients who underwent surgery achieved an R0 resection (microscopically margin-negative resection), providing a solid foundation for curative intent and potentially reducing the risk of recurrence.

Significant Tumor Downstaging

Among all evaluable patients, 85.7% achieved downstaging of the primary tumor (ypT), and 75.0% achieved nodal downstaging (ypN). These results confirm the efficacy of the cadonilimab regimen in reducing tumor burden and lowering the pathological stage, thereby improving the conditions for successful surgical intervention.

Manageable Safety Profile with Good Tolerability

Treatment-related adverse events were consistent with the known safety profiles of the SOX regimen and immune checkpoint inhibitors. No new or unexpected safety signals were observed, indicating an overall manageable and favorable safety profile.

In perioperative treatment of resectable G/GEJ adenocarcinoma, chemotherapy remains the standard therapy for locally advanced gastric cancer. However, chemotherapy has limited efficacy. Cadonilimab, the first PD-1/CTLA-4 bispecific antibody, works by synergistically activating the immune system, achieving a dual blockade of the tumor immune suppressive microenvironment. This mechanism provides a stronger anti-tumor effect compared to PD-1/L1 monotherapies.

Currently, cadonilimab's clinical value in gastric cancer is scientifically well-established. Beyond its ongoing phase III clinical trial in the perioperative setting, cadonilimab combined with chemotherapy as a first-line treatment for advanced gastric cancer (with survival benefits across the PD-L1 expression levels) has been approved for commercialization in China. Additionally, a pivotal phase III trial exploring cadonilimab in combination with pulocimab (VEGFR-2) for immune therapy-resistant advanced gastric cancer is currently ongoing and is expected to offer a new therapeutic option for later-line gastric cancer. Collectively, these pivotal phase III studies will expand the use of cadonilimab, paving the way for a comprehensive gastric cancer treatment options that spans from advanced, unresectable gastric cancer to early-stage, resectable disease.

Forward-Looking Statement of Akeso, Inc.

This announcement by Akeso, Inc. (9926.HK, "Akeso") contains "forward-looking statements". These statements reflect the current beliefs and expectations of Akeso's management and are subject to significant risks and uncertainties. These statements are not intended to form the basis of any investment decision or any decision to purchase securities of Akeso. There can be no assurance that the drug candidate(s) indicated in this announcement or Akeso's other pipeline candidates will obtain the required regulatory approvals or achieve commercial success. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in P.R.China, the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; Akeso's ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the Akeso's patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

Akeso does not undertake any obligation to publicly revise these forward-looking statements to reflect events or circumstances after the date hereof, except as required by law.

About Akeso

Akeso (HKEX: 9926.HK) is a leading biopharmaceutical company committed to the research, development, manufacturing and commercialization of the world's first or best-in-class innovative biological medicines. Founded in 2012, the company has created a unique integrated R&D innovation system with the comprehensive end-to-end drug development platform (ACE Platform) and bi-specific antibody drug development technology (Tetrabody) as the core, a GMP-compliant manufacturing system and a commercialization system with an advanced operation mode, and has gradually developed into a globally competitive biopharmaceutical company focused on innovative solutions. With fully integrated multi-functional platform, Akeso is internally working on a robust pipeline of over 50 innovative assets in the fields of cancer, autoimmune disease, inflammation, metabolic disease and other major diseases. Among them, 26 candidates have entered clinical trials (including 15 bispecific/multispecific antibodies and bispecific ADCs. Additionally, 7 new drugs are commercially available. Through efficient and breakthrough R&D innovation, Akeso always integrates superior global resources, develops the first-in-class and best-in-class new drugs, provides affordable therapeutic antibodies for patients worldwide, and continuously creates more commercial and social values to become a global leading biopharmaceutical enterprise.

SOURCE Akeso, Inc.