On September 28, 2023, Akeso (9926.HK) announced that its subsidiary, Akeso Pharma, will collaborate with RemeGen (Yantai) Co., Ltd. (688331.SH/09995.HK) to advance the development of Akeso's globally first PD-1/CTLA-4 bispecific antibody, cadonilimab (trade name: 开坦尼®), and RemeGen's first domestically developed antibody-drug conjugate (ADC) injection, Disitamab Vedotin (trade name: 爱地希®) in combination therapy. The collaboration will also initiate a phase II clinical study for gastric cancer.

Cadonilimab is a human tetravalent bispecific IgG1 antibody with symmetric IgG-single-chain variable fragment (scFv) structure that targets both PD-1 and CTLA-4. It has shown higher affinity for tumor-infiltrating lymphocytes (TILs) than for surrounding tissues in the tumor microenvironment (TME). With Fc-null design, cadonilimab contributes to better safety compared to combination of anti-PD-1 and anti-CTLA-4 antibodies while fully exerting the synergistic anti-tumor effects of inhibiting PD-1 and CTLA-4 immune checkpoints.

Cadonilimab has shown excellent anti-tumor efficacy in clinical trials for various solid tumors. According to the two-year follow-up data presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, cadonilimab demonstrated a high overall response rate and long-term survival benefit in the first-line treatment of advanced gastric/esophagogastric junction adenocarcinoma in the entire population (regardless of PD-L1 expression). The study results also indicate that cadonilimab has the potential to overcome the limited efficacy of immunotherapy in populations with low PD-L1 expression or negative PD-L1 expression, making it a superior immunotherapeutic option for patients with advanced gastric cancer.

爱地希® (Disitamab Vedotin) utilizes a novel, highly affinity, and better internalization effect humanized antibody, Disitamab Vedotin monoclonal antibody, combined with advanced linker and small molecule cytotoxic drugs. It demonstrates specific targeting abilities, exceptional efficacy, and excellent safety profiles. The study results have been presented at major domestic and international conferences such as the ASCO Annual Meeting.

The 2023 version of the Chinese Society of Clinical Oncology (CSCO) Guidelines for Diagnosis and Treatment of Gastric Cancer, announced in April this year, recommends Disitamab Vedotin as a preferred third-line treatment for HER2-positive (IHC3+ or 2+) advanced gastric cancer, upgrading its recommendation level from "Grade II Recommendation" to "Grade I Recommendation."

Multiple preclinical studies have demonstrated the synergistic and enhanced efficacy of immune checkpoint inhibitors in combination with ADC drugs. The combination therapy of cadonilimab and Disitamab Vedotin has a solid theoretical basis and may achieve synergistic efficacy in anti-tumor treatment, potentially bringing a new generation of more efficient and safer combination therapy for cancer patients.

Currently, Akeso is fully committed to advancing the exploration of cadonilimab as a cornerstone cancer treatment by developing more combination therapies. This includes not only the development of combination therapies with the Akeso's self-developed innovative product pipeline but also the development of combination therapies with new molecules and mechanisms within the industry that have excellent clinical value potential, in order to fully tap into the clinical value of cadonilimab.