Cadonilimab Demonstrates Manageable Toxicity and Promising Efficacy in Heavily Pretreated Solid Tumor Patients

Strategic Insights -

Researchers at Peking University Third Hospital have conducted a phase 1b study to evaluate the safety and efficacy of stereotactic body radiotherapy (SBRT) combined with cadonilimab, a humanized immunoglobulin G1 bispecific antibody targeting programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4). The study involved 63 patients with advanced recurrent or refractory solid tumors who had progressed after at least two lines of systemic treatment, including immunotherapy. The patients received SBRT in combination with intravenous cadonilimab, and the primary endpoint was safety.

Patients received cadonilimab at a dose of 6 mg/kg every 2 weeks, and the median follow-up was 9.1 months. The most common treatment-related adverse events (TRAEs) included pain, elevated transaminases, pneumonia, fatigue, nausea, and fever, with a grade 3 TRAE rate of 3.2%. The objective response rate (ORR) was 23.8%, with a median progression-free survival (PFS) of 7.2 months and a median overall survival (OS) of 10.0 months.

A subgroup analysis of 23 non-small cell lung cancer patients showed an ORR of 17.4%, a median PFS of 6.9 months, and a median OS of 9.1 months. Multivariate analysis indicated that receiving ≥ 6 cycles of cadonilimab and having an Eastern Cooperative Oncology Group performance status score of 0-1 were significantly associated with improved PFS and OS.

Key Takeaways:

  • The phase 1b study of SBRT combined with cadonilimab demonstrated manageable toxicity and promising efficacy in heavily pretreated patients with refractory solid tumors.
  • Treatment-related adverse events (TRAEs) occurred in 38.1% of patients, with a grade 3 TRAE rate of 3.2%.
  • The most common TRAEs included pain, elevated transaminases, pneumonia, fatigue, nausea, and fever.
  • The objective response rate (ORR) was 23.8%, with a median progression-free survival (PFS) of 7.2 months and a median overall survival (OS) of 10.0 months.
  • A subgroup analysis of 23 non-small cell lung cancer patients showed an ORR of 17.4%, a median PFS of 6.9 months, and a median OS of 9.1 months.
  • Multivariate analysis indicated that receiving ≥ 6 cycles of cadonilimab and having an Eastern Cooperative Oncology Group performance status score of 0-1 were significantly associated with improved PFS and OS.

Statistics:

  • 63 patients were enrolled in the study.
  • The median follow-up was 9.1 months.
  • 38.1% (24/63) of patients experienced treatment-related adverse events (TRAEs).
  • 3.2% (2/63) of patients experienced grade 3 TRAEs.
  • The objective response rate (ORR) was 23.8% (95% CI, 14.0%-36.2%).
  • The median progression-free survival (PFS) was 7.2 months (95% CI, 6.3-8.2 months).
  • The median overall survival (OS) was 10.0 months (95% CI, 7.7-12.4 months).
  • 98.4% (61/63) of patients achieved 6-month local control.
  • 93.0% (58/63) of patients achieved 12-month local control.

Sources:

  • NewsRx. Studies from Peking University Third Hospital Have Provided New Data on Solid Cancer [Stereotactic Body Radiotherapy Plus Cadonilimab (Pd-1/ctla-4 Bispecific Antibody) As Third-line or Beyond Therapy for Refractory Solid Tumors: a Phase 1b Study]. Immunotherapy Weekly. August 20, 2025; p 2767.
  • Stereotactic Body Radiotherapy Plus Cadonilimab (Pd-1/ctla-4 Bispecific Antibody) As Third-line or Beyond Therapy for Refractory Solid Tumors: a Phase 1b Study. Cancer Communications, 2025.