Incorporation of PD-1 blockade into induction chemotherapy improved tumor response in patients with locoregionally advanced nasopharyngeal carcinoma in a retrospective patient cohort.

OBJECTIVE: To investigate the short-term efficacy and safety of induction chemotherapy (IC) combined with anti-PD-1 immunotherapy in locoregionally advanced nasopharyngeal carcinoma (LA-NPC). METHODS: A total of 217 patients diagnosed with LA-NPC at the First Affiliated Hospital of Nanchang University, including 67 who received IC combined with anti-PD-1 and 150 who received IC, were retrospectively enrolled. Efficacy was evaluated at the end of the IC cycles and one month after radiotherapy based on RECIST v1.1 criteria. Acute toxicities were graded based on the CTCAE v5.0 criteria. Quantitative variables were compared by unpaired t-tests, and categorical variables were evaluated by Fisher Freeman-Halton test or Pearson Chi-square test. RESULTS: At the end of all induction therapy cycles, the objective response rate (ORR) of the IC + anti-PD-1 group was 88.1 % (59/67) as opposed to 70.0 % (105/150) in the IC group. Subgroup analysis showed that patients in both stage Ⅲ and ⅣA achieved a significant improvement in ORR with the inclusion of anti-PD-1 therapy. Patients with T3-4 or N2-3 category appeared to benefit more from anti-PD-1 compared to patients with T1-2 or N0-1 category. However, neither ORR nor the complete response (CR) rate was significantly different between the two treatment groups one month after the end of radiotherapy. In addition, the frequency of Grade 3-4 adverse events were also similar in both groups. CONCLUSIONS: IC combined with anti-PD-1 immunotherapy significantly improved the ORR of LA-NPC patients after induction therapy compared to IC alone.