Objective: This study was designed to assess the efficacy and safety of cadonilimab monotherapy, a first-in-class, bi-specific PD-1/CTLA-4 antibody, in patients with previously treated recurrent or metastatic nasopharyngeal carcinoma (R/M-NPC).
Patients and methods: This multicenter, open-label, single-arm, phase II clinical trial enrolled patients with R/M-NPC who had failed first-line platinum-based chemotherapy and second-line single agent or combined chemotherapy, and immunotherapy-naive. Patients received cadonilimab for 6 mg/kg once every 2 weeks (Q2W). The primary endpoint was objective response rate (ORR) in full analysis set (FAS) assessed by investigators according to RECIST v.1.1. The secondary endpoint included progression-free survival (PFS), overall survival (OS), duration of response (DoR), time to response (TTR) and safety.
Results: A total of 23 patients were assessed. The median time from first dose to data cutoff was 16.56 (range, 0.8-25.2) months. ORR was 26.1 % (95 %CI:10.2-48.4). The ORR were 44.4 % (95 %CI: 13.7-78.8) and 14.3 % (95 %CI:1.8-42.8) in patients with tumor PD-L1 expression ≥50 % and <50 %, respectively. ORR was achieved in 40.0 % (95 %CI:12.2-73.8) of patients with EBV-DNA level <4000 IU/ml (n = 10) and 15.4 % (95 %CI:1.9-45.4) of those with ≥4000 IU/ml. The median PFS was 3.71 months (95 %CI: 1.84-9.30). respectively. Median OS was not reached, and the 12-month OS rate was 79.7 % (95 % CI:54.5-91.9). Only two patients (8.3 %) experienced Grade ≥3 treatment-related adverse events (TRAEs) with hypothyroidism (30.4 %), rash (21.7 %) and pruritus (21.7 %) being the most prevalent TRAEs.
Conclusion: Cadonilimab monotherapy demonstrated a promising efficacy and manageable toxicity in patients with previously treated R-M/NPC and provide an efficacious salvage treatment option.
Keywords: Bi-specific antibody; BsA; Cadonilimab; Immune checkpoint inhibitor; Immunotherapy; NPC; Nasopharyngeal carcinoma.
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