A Randomized, Multicenter, Phase 2 Trial of Camrelizumab With or Without Metastasis-directed Stereotactic Body Radiation Therapy in Recurrent or Metastatic Nasopharyngeal Carcinoma

Purpose: To investigate the efficacy of metastasis-directed therapy (MDT) when added to camrelizumab (Cam) in patients with recurrent or metastatic nasopharyngeal carcinoma (R/M-NPC).

Methods and materials: We conducted a randomized, controlled, multicenter, phase 2 trial in 3 centers from China (NCT04830267). Patients with R/M-NPC, without prior exposure to immunotherapy, who presented with ≥2 lesions, and at least 1 measurable lesion were randomized 1:1 to either Cam alone or Cam plus MDT (Cam+MDT). Patients randomized to the MDT group must have 1 lesion that is amendable to stereotactic body radiation therapy (SBRT) prescribed to 27 Gy in 3 fractions every other day. The primary endpoint was objective response rate (ORR) of unirradiated lesions using Response Evaluation Criteria in Solid Tumors v1.1.

Results: Between April 2021 and August 2023, 39 patients were randomly assigned to receive either Cam (n = 20) or Cam+MDT (n = 19). In total, 17 out of 39 (43.6%) patients had oligometastatic disease (≤3 lesions), 18 out of 39 (46.2%) had liver involvement, and 3 out of 39 (7.7%) had locoregional recurrent disease. ORR of unirradiated lesions did not differ between the treatment groups (26.3% [Cam+MDT] vs 30.0% [Cam], P = 1.0). The disease control rate of unirradiated lesions was 73.7% in the Cam+MDT group compared with 60.0% in the Cam group (P = .571). After a median follow-up of 25.8 months, median progression-free survival was 9.3 (95% CI, 6.2-not reached [NR]) months in the Cam+MDT group and 8.8 (95% CI, 3.3-NR) months in the Cam group (P = .750). Exploratory analyses suggested a longer overall survival (OS) with Cam+MDT for patients with >3 lesions (HR, 0.23; 95% CI, 0.07-0.77; P = .009). G3 and above adverse events were comparable between the treatment groups (15.8% [Cam+MDT] vs 20.0% [Cam]). The overall rate of capillary proliferation was 17.9% (7/39) for the trial.

Conclusions: Our study did not meet its primary endpoint of superior ORR of unirradiated lesions with the addition of MDT to Cam in patients with R/M-NPC.