Abstract 882P
Background
Immune checkpoint inhibitors (ICI) in recurrent or metastatic head and neck cancer has shown clinical activity, but the objective response rate for single-agent ICI therapy is poor. We aimed to test whether anti-PD-1 antibody may act synergistically with chemoradiotherapy to improve responses.
Methods
We conducted a retrospective study of anti-PD-1 antibody combined with chemoradiotherapy in pts with recurrent or metastatic head and neck cancer from August 2018 to April 2021. 15 pts received a 60–68Gy total dose (2.0–2.2Gy per session) for recurrent lesions, 37 pts received SBRT for 1-4 metastases lesions with the median dose of 64Gy (BED 39-100Gy), anti-PD-1 antibody (pembrolizumab or toripalimab or camrelizumab or sintilimab) and platinum were given during radiotherapy. ORR was the primary outcome and DOR and PFS were secondary outcomes.
Results
Of 52 efficacy-evaluable pts, 38 were men, median age was 50 (24-75) years. Primary site was nasopharynx (N=32) and non-nasopharynx (N=20). 37 had metastatic and 15 recurrent disease. After a median follow-up of 11.2 months (range 1-27months), ORR and DCR were 76.9% (95% CI 65.4-88.4%) and 92.3% (95% CI 85.1-99.5%). ORR of nasopharynx and non-nasopharyngeal pts was 87.5% and 60% respectively (P=0.022). ORR of local recurrence and distant metastases pts was 78.4% and 73.3% respectively (P=0.696). Median DOR was 15months (95% CI: 10.0-20.1months), median PFS was 15.0 months (95% CI: 9.0–20.9months), 6-month and 1-year PFS rate were 76.4% and 57.7%. Median overall survial was not reached. Nasopharynx had significantly longer survival compared to non-nasopharyngeal pts (mPFS: 18 vs.7months, P=0.000), and local recurrence pts had a trend towards better survival than distant metastases (mPFS 18 vs. 15months, P=0.952). The most common treatment-related adverse events above grade 3 were leucopenia (31.3%), neutropenia (18.8%) and thrombocytopenia (12.5%). 22 pts received chest radiotherapy and 27.3% of pts had all grades of radiation-induced pneumonia events.
Conclusions
Anti-PD-1 antibody in combination with chemoradiotherapy shows a promising activity in patients with recurrent or metastatic head and neck cancer and an acceptable toxicity.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Sichuan Science and technology program (fund No. 2021JDRC0146); Immunoradiotherapy research fund project of radiotherapy and Oncology Society of Chinese Medical Association (fund No. Z-2017-24-2020).
Disclosure
All authors have declared no conflicts of interest.