Circulating T cell status and molecular imaging may predict clinical benefit of neoadjuvant PD-1 blockade in oral cancer.

Background: Addition of neoadjuvant immune checkpoint inhibition to standard-of-care interventions for locally advanced oral cancer could improve clinical outcome.
Methods: In this study, 16 evaluable patients with stage III/IV oral cancer were treated with one dose of 480 mg nivolumab 3 weeks prior to surgery. Primary objectives were safety, feasibility, and suitability of programmed death receptor ligand-1 positron emission tomography (PD-L1 PET) as a biomarker for response. Imaging included ¹⁸ F-BMS-986192 (PD-L1) PET and ¹⁸ F-fluorodeoxyglucose (FDG) PET before and after nivolumab treatment. Secondary objectives included clinical and pathological response, and immune profiling of peripheral blood mononuclear cells (PBMCs) for response prediction. Baseline tumor biopsies and postnivolumab resection specimens were evaluated by histopathology.
Results: Grade III or higher adverse events were not observed and treatment was not delayed in relation to nivolumab administration and other study procedures. Six patients (38%) had a pathological response, of whom three (19%) had a major (≥90%) pathological response (MPR). Tumor PD-L1 PET uptake (quantified using standard uptake value) was not statistically different in patients with or without MPR (median 5.3 vs 3.4). All major responders showed a significantly postnivolumab decreased signal on FDG PET. PBMC immune phenotyping showed higher levels of CD8 ⁺ T cell activation in MPR patients, evidenced by higher baseline expression levels of PD-1, TIGIT, IFNγ and lower levels of PD-L1.
Conclusion: Together these data support that neoadjuvant treatment of advanced-stage oral cancers with nivolumab was safe and induced an MPR in a promising 19% of patients. Response was associated with decreased FDG PET uptake as well as activation status of peripheral T cell populations.
Competing Interests: Competing interests: RvdV has received research funding from Genmab BV. TDdG is scientific advisor to Immunicum, GE Health, and Lava Therapeutics, holds stock from LAVA Therapeutics and received research funding from Idera Pharmaceuticals (now Aceragen). RHB received research grants from KWF Kankerbestrijding/Dutch Cancer Society, Cancer Center Amsterdam Foundation, ZonMW and NWO, Genmab BV and the Hanarth Foundation and is on the advisory board of Nanobiotix. He has a scientific collaboration with Orfenix BV and Qialix DoT. CRL received research grants from KWF Kankerbestrijding/Dutch Cancer Society, Cancer Center Amsterdam Foudation, Genmab BV, BMS and the Hanarth Foundation and is on the advisory board of Merck & Co. CWM-vdHvO received research grants from BMS, Boeringher Ingelheim, GSK, Pfizer and AstraZeneca and consulted for GE Health Care, Novartis and EliLilly. All other authors report no competing interests.
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