A phase 1a/1b first-in-human study (COMPASSION-01) evaluating cadonilimab in patients with advanced solid tumors.

Simultaneous inhibition of programmed cell death protein-1 (PD-1) and cytotoxic T lymphocyte-associated protein-4 (CTLA-4) with bispecific antibodies may improve efficacy over single-agent treatment while limiting toxicity. Cadonilimab is a humanized, bispecific antibody targeting PD-1 and CTLA-4. This is a phase 1 study of cadonilimab including dose escalation (n = 39) and dose expansion (n = 80). One dose-limiting toxicity event is observed, with the maximum tolerated dose not reached. 6 mg/kg cadonilimab once every 2 weeks is established as the recommended dose for future studies. The most common treatment-related adverse event is infusion-related reaction (18.5%), mostly grade 1/2 in severity. The incidences of any grade and grade ≥3 immune-related adverse events are 44.5% and 6.7%, respectively. The confirmed overall response rate is 13.4%, and the median duration of response is 12.9 months. Cadonilimab is well tolerated and showed promising efficacy in patients with advanced solid tumors. This study is registered with ClinicalTrials.gov: NCT03261011.