A phase II exploratory study (NCT06208826) on maintenance immunotherapy in patients with resectable locally advanced head and neck cancer who achieved MPR after neoadjuvant immunotherapy combined with chemotherapy.

Abstract

e18083 Background: Induction chemotherapy could improve functional preservation but could not provide long-term survival benefits in head and neck squamous cell carcinoma (HNSCC). Immunotherapy has achieved great success in the salvage treatment of recurrence and metastasis HNSCC. Many clinical studies have found that lots of patients (pts) achieved a major pathologic response (MPR)after neoadjuvant immunotherapy combined with chemotherapy. Nevertheless, the optimal subsequent treatment for pts who have attained MPR remain to be further explored. Methods: This was a randomized, controlled, open label, phase II study. 268 pts were planned to enrolled. Key inclusion criteria: Head and neck squamous cell carcinoma pts with MPR after neoadjuvant immunotherapy combined with chemotherapy. Eligible pts were randomly assigned (1:1) to receive toripalimab (240mg, D1, q3w) for 15cycles (experimental arm) or routine treatment (control arm). The primary endpoint was disease free survival (DFS). Secondary endpoints were overall survival (OS) and safety. Results: As of Jan. 2025, 57 pts were enrolled (experimental 29, control 28). Median age of the enrolled pts was 61years (range: 33–76) and 91.23% were male.73.68% of them achieved a pathological complete response (pCR)..Median follow-up time is 8.8 months，and the longest follow-up time is 22 months. In the experimental group, 1 case died of unknown cause and 1 case died of secondary primary pancreatic cancer. No death occurred in the control group. At present, the data on DFS and OS are immature. There was no significant difference in 1-year DFS rate (experimental 91.83%, control 95.53%), or 1-year OS rate (experimental 88.99%, control 100%) between the two groups. In the control arms, the proportion of Grade ≥3 treatment-related adverse events (TRAEs) was higher (experimental 24.14%, control 42.86%). No new safety signals were observed and no TRAEs led to death. Conclusions: Compared with routine treatment, maintenance immunotherapy has not shown a decline in survival on pts who achieved MPR after neoadjuvant immunotherapy combined with chemotherapy. Moreover, maintenance immunotherapy has higher safty. Therefore, maintenance immunotherapy is expected to become a new alternative postoperative adjuvant therapy. Clinical trial information: NCT06208826 .