378P - A real-world retrospective analysis of the efficacy of pembrolizumab combined with chemotherapy as neoadjuvant treatment for locally advanced head and neck squamous cell carcinoma (LA HNSCC)

Background

Pembrolizumab combined with chemotherapy has already become the standard first-line treatment for R/M HNSCC. However, data on pembrolizumab in LA HNSCC remains limited, primarily focusing on monotherapy. This study aimed to analyze and explore the efficacy and safety of pembrolizumab combined with chemotherapy as a neoadjuvant treatment.

Methods

A single center, retrospective real-world study was conducted using the database. We included adult resectable LA HNSCC patients who received pembrolizumab plus TP or DP as neoadjuvant therapy between 2021-09-01 and 2023-06-10. Patients were excluded if their histopathological diagnosis was non-squamous cell carcinoma, had received systemic treatment before. Primary endpoint was ORR, and secondary endpoint were pCR and 1y-DFS.

Results

A Total of 21 patients with resectable LA HNSCC were Included. The baseline showed that the median age was 61. PS=0 (19/21), PS=1 (2/21). The location of primary site: oral was 38.1% (8/21); oropharynx was 33.3% (7/21); hypopharyngeal were 23.8% (5/21); sinus was 4.8% (1/21). TNM stage: stage II was 14.3% (3/21); stage III was 38.1% (8/21); stage IVA was 42.6% (9/21); stage IVB was 4.8% (1/21) . CPS status showed 62.0% (13/21) patients were CPS ≥ 20, 38.1% （8/21）1≤CPS＜20. 4 (19.0%) patients received 2 cycles, other patients got 3-5 cycles. No grade ≥3 TRAEs detected during neoadjuvant therapy. ORR was 90.5% (19/21), 3 patients achieved CR, and ORR in CPS≥20 was 100%, while 62.5% in CPS＜20. In total 13 (62.0%) patients underwent surgery after neoadjuvant therapy, 4 (19.0%) patients did not undergo surgery but received radiation therapy, and the remaining patients have not yet decided on the follow-up treatment plan. pCR reached 72.7% (8/11), pCR+MPR was 100%, and pCR was 75.0% (6/8) in CPS≥20, 33.3% (1/3) in CPS＜20 . pCR (≥3 cycles) was 87.5% (7/8) and pCR(2 cycles) was 33.3% (1/3).1y-DFS data is not yet mature.

Conclusions

This study shows that pembrolizumab combined with chemotherapy as a neoadjuvant therapy for LA HNSCC has excellent short-term curative effect and good security. Patients with high CPS expression and long cycles of treatment can see higher pCR.

Clinical trial identification

Editorial acknowledgement

We thank Hui Li and Binjie Li from MSD China Medical Affair oncology team for giving scientific support to the abstract.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.