A novel neoadjuvant immunotherapy confers improved overall survival in oral cancer patients with low tumor PD-L1 expression The IT-MATTERS Clinical trial – Prognostic role of tumor PD-L1 expression

Objective Five-year overall survival (OS) remains < 50% for patients with resectable, locally advanced (LA) primary oral squamous cell carcinoma (OSCC) and soft palate, receiving current standard of care (SOC). The aim of our study was to examine neoadjuvant Leukocyte Interleukin Injection (LI) with CIZ (intravenous low dose cyclophosphamide, indomethacin and zinc multivitamins) effect on OS, in low-risk (LR) OSCC patients. Patients and Methods In a randomized, controlled Phase 3 trial, treatment-naïve locally advanced patients, with stage III/IVa OSCC and soft-palate cancer, had surgical tumor samples assessed for pre-defined thresholds of PD-L1 tumor proportion score (TPS). OS was analyzed using proportional hazard models for LI + CIZ + SOC vs SOC, in the intention-to-treat (ITT) population. Results OS was superior in low risk (LR) patients receiving LI + CIZ + SOC compared to SOC; OS advantage hazard ratio (HR) 0.64, p = 0.0569 (without selecting for N0, PD-L1 TPS < 10%), and the Kaplan-Meier (K-M) lifetable achieved significance (log rank p = 0.0340) favoring LI + CIZ + SOC vs SOC. Applying the selection criteria (cN0 and TPS < 10%) to ITT, OS reached HR 0.34p = 0.0012, Kaplan-Meier log rank p = 0.0015. The ITT LR cohort (cN0 and TPS < 10%) achieved a HR 0.26 (p = 0.0023), Kaplan-Meier log rank p = 0.0013, supported by progression free survival (PFS) HR 0.43, p = 0.0178, Kaplan-Meier log rank p = 0.0431, with 32% absolute survival advantage over control at 60 months. Conclusions. Significant OS prolongation was observed in ITT population for LI + CIZ + SOC vs SOC, in LR and in ITT LR cN0, PD-L1TPS < 10% cohort having locally advanced squamous cell carcinoma tumors in oral cavity/soft-palate. Trial Registration Clinicaltrials.gov Identifier: NCT01265849; EudraCT (Identifier: 2010–019952-35).