Camrelizumab plus apatinib after progression on immune checkpoint inhibitors in patients with advanced esophageal squamous cell carcinoma (CAP 02 Re-challenge): A single-arm multicenter, phase II trial.

364 Background: The optimal therapies for patients with advanced esophageal squamous cell carcinoma (ESCC) who have progressed after immune checkpoint inhibitors (ICIs) are unclear. This phase II single-arm study aimed to assess the efficacy and safety of re-challenge with camrelizumab plus apatinib in this population. Methods: This study enrolled patients with unresectable locally advanced, locally recurrent, or metastatic ESCC who had experienced prior progression on ICI treatment. Enrolled patients received camrelizumab 200 mg intravenously every two weeks along with daily oral apatinib 250 mg. Treatment continued until disease progression, unacceptable toxicity, or patient withdrawal of consent. The primary endpoint was the confirmed objective response rate (ORR). Secondary endpoints included disease control rate (DCR), duration of response (DOR), time to response (TOR), progression-free survival (PFS), overall survival (OS), 3- and 6-month PFS rates, 6-, 9- and 12-month OS rates, and safety. Results: From September 1, 2021, to March 29, 2023, 49 eligible patients were enrolled and given treatment. Among 38 treated patients who had at least one post-baseline efficacy measurement, the ORR and confirmed ORR were 36.8% (95% CI 21.8–54.0) and 13.2% (95% CI 4.4–28.1); the DCR was 89.5% (95% CI 75.2–97.1); the median DOR was 3.0 months; and the median TOR was 2.2 months. Among the 49 treated patients, the median PFS was 4.6 months (95% CI 3.8–6.5) and OS was 7.5 months (95% CI 5.5–13.6). Patients who were both PD-L1 positive and had responded to previous ICI therapy had the longest median PFS (5.7 months, 95% CI 3.9–not reached) and OS (9.6 months, 95% CI 7.5–not reached). Grade ≥ 3 treatment-related adverse events occurred in 34.7% of patients (17/49). Conclusions: This study showed promising efficacy and an acceptable safety profile of camrelizumab plus apatinib for patients with advanced ESCC who had progressed after ICI therapy. The subset of patients who were both PD-L1 positive and had a prior ICI response seemed to benefit most. Clinical trial information: NCT03736863 .