858P - Preoperative neoadjuvant chemoimmunotherapy for locally advanced head and neck squamous cell carcinoma patients: A prospective, single-arm, phase II clinical study

Background

Neoadjuvant chemoimmunotherapy has emerged as a potential treatment option for resectable head and neck squamous cell carcinoma (HNSCC). This study aimed to investigate the efficacy and safety of combining immune checkpoint blockade (ICB) with neoadjuvant chemotherapy (NAC) in patients with locally advanced HNSCC (LA HNSCC), focusing on the pathological complete response (pCR) rate and objective response rate (ORR).

Methods

In this prospective, single-arm, phase II clinical trial (ChiCTR2200055809), LA HNSCC patients meeting the inclusion criteria received neoadjuvant chemoimmunotherapy with pembrolizumab (200 mg), cisplatin (75mg/m²), and 5-Fluorouracil (750μg/m²) intravenously on day one of each three-week cycle for three cycles, followed by radical surgery and adjuvant (chemo)radiotherapy. The primary endpoint was pCR, and secondary endpoints included ORR, major pathologic response (MPR), two-year progression-free survival rate, two-year overall survival rate, and toxicities. Additionally, pre-treatment tissue samples from patients achieving pCR and non-pCR were used for single-cell transcriptome sequencing analysis to identify specific immune cell subpopulations. All statistical analyses were performed using SPSS 24.

Results

A total of 51 patients were enrolled for this interim analysis. 30 achieved a pCR, resulting in a pCR rate of 58.8%. The ORR was 88.2%. Treatment-related adverse events of grade 3 or 4 occurred in 4 patients. There was no delay to surgery due to adverse drug reactions. The median follow-up time was 18.2 months, and only one patient (2.0%) suffered a regional recurrence. Survival outcomes were not mature at the time of data analysis. Furthermore, the single-cell transcriptome sequencing analysis revealed distinct immune cell subpopulations in pre-treatment tissue samples from patients achieving pCR.

Conclusions

The combination of pembrolizumab with NAC demonstrated a promising pathological response rate and ORR without increasing the risk of toxicity. These findings provide valuable pathological evidence for the use of NAC and ICB treatment in LA HNSCC patients.

Clinical trial identification

ChiCTR2200055809.

Editorial acknowledgement

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.