865P - Adjuvant toripalimab for locally advanced head and neck squamous cell carcinoma patients who achieved pathological complete response after neoadjuvant immunochemotherapy and surgery: A single-arm, phase II trial

Background

Neoadjuvant immunochemotherapy (NICT) showed favorable efficacies and anticipated outcomes for locally advanced head and neck squamous cell carcinoma (LA-HNSCC). However, optimal adjuvant therapy remains uncertain for LA-HNSCC patients who achieved pathological complete response (pCR) after NICT and surgery. This study aimed to explore an optimal adjuvant strategy with low-toxicity and survival benefits for these patients.

Methods

In this single-arm, phase II trial, 25 LA-HNSCC patients were planned to be enrolled. Key inclusion criteria were: pathologically confirmed LA-HNSCC patients (stage III-IVB for non-oropharyngeal cancers and HPV-negative oropharyngeal cancer; stage II-III or stage I with adverse features for HPV-positive oropharyngeal cancer, according to the 8th edition of the AJCC staging manual), receipt of at least 1 cycle of NICT (platinum-based chemotherapy and anti-PD-1 immunotherapy) and surgical resection, and achievement of pCR to the primary tumor and regional lymph nodes. Eligible patients received adjuvant immunotherapy with toripalimab (240mg) on day 1 of each 21-day cycle for 8 cycles. The primary end point was 2-year disease-free survival rate. Secondary end points included 2-year overall survival rate, 2-year disease specific survival rate, quality of life, and safety.

Results

Up to April, 2024, 22 patients were enrolled and 18 finished the planned therapy. The median age was 52 years (29-75) and 86.4% were males. After a median follow-up time of 8.3 months, only 1 (4.5%) patient suffered local recurrence and underwent salvage surgery, while no deaths occurred. Most common treatment-related adverse events (TRAEs) included increased blood creatinine (22.7%), skin toxicity (13.6%), and hypothyroidism (9.1%). 2 (9.1%) patients experienced grade 3 TRAEs including 1 (4.5%) anaemia and 1 (4.5%) ulcerative colitis.

Conclusions

For LA-HNSCC patients who achieved pCR after NICT and surgery, adjuvant immunotherapy with toripalimab showed promising efficacy and tolerable toxicity. This study is ongoing and further follow-up is needed to confirm the long-term efficacy.

Clinical trial identification

ChiCTR2300067960.

Editorial acknowledgement

Funding

Has not received anyfunding.

Disclosure

All authors have declared no conflicts of interest.