Abstract 1237: Randomized phase II trial of pre-operative afatinib in non-metastatic head and neck squamous cell carcinoma patients: Identification of predictive biomarkers of response

Abstract Background: Epidermal growth factor receptor (EGFR) inhibitors, including monoclonal antibodies and tyrosine kinase inhibitors, have limited efficacy in head and neck squamous cell carcinoma (HNSCC) patients. In the randomized phase II PREDICTOR trial, we aimed at identifying predictive and pharmacodynamics biomarkers of 2-4 weeks afatinib (an irreversible pan-HER inhibitor) versus no treatment in the pre-operative setting (NCT01415674). We previously reported a 59% metabolic response rate on PET imaging in the afatinib arm. We report here the evaluation of predictive genomic and transcriptomic biomarkers of afatinib efficacy. Patients and Methods: All patients (41 in the afatinib arm and 20 in the no treatment arm) underwent a pre-treatment biopsy. We performed targeted DNA sequencing using an in-house NGS panel of 571 genes on baseline biopsies from 56 patients, and RNA-sequencing (RNAseq) in 54 patients. In the afatinib arm, 26 patients had paired pre- and post-treatment tumor samples. DNA and RNA alterations were correlated with metabolic response to afatinib using PET imaging, as well as overall survival (OS). Results: Most frequent molecular alterations, including known activating mutations and/or focal amplifications for oncogenes or homozygous deletions and inactivating mutations for tumor suppressor genes, involved genome integrity (TP53 [70%]), cell cycle (CCND1 [38%], CDKN2A [32%], CDKN2B [14%]), senescence (TERT [23%]), Wnt signaling (NOTCH1 [16%]), and the PI3K pathway (PIK3CA [14%]). In the afatinib arm, metabolic response was observed in 1 out of 7 patients (14%) and in 19 out of 28 patients (68%) in the Wnt altered and unaltered groups (p = 0.03, fisher exact test), respectively. In the whole cohort of patients, homozygous deletions of both CDKN2A and CDKN2B correlated with shorter OS, with 6-year survival of 22% in the CDKN2A/B altered group and 70% in the CDKN2A/B wild-type group (p = 0.004; log-rank test). In the afatinib treated patients, using a generalized linear mixed model with a patient as random effect and a quasi-binomial family, the ratio of B cells expression levels in the post-treated versus pre-treated samples was significantly higher in responder as compared to non-responder patients (p = 0.001). Conclusions: Wnt signaling pathway alterations and treatment-related dynamic changes in B cells proportions were identified as predictive and pharmacodynamics biomarkers of afatinib efficacy. CDKN2A/B homozygous deletions were associated with a poor prognosis in HNSCC patients treated with upfront surgery. Citation Format: Grégoire Marret, Maud Kamal, Jocelyn Gal, Stéphane Temam, Jerzy Klijianenko, Jean-Pierre Delord, Caroline Hoffmann, Gilles Dolivet, Olivier Malard, Jerôme Fayette, Olivier Capitain, Caroline Even, Sébastien Vergez, Lionel Geoffrois, Frédéric Rolland, Philippe Zrounba, Laurent Laccourreye, Joël Guigay, Nicolas Aide, Valérie Bénavent, Constance Lamy, Elodie Girard, Marta Jimenez, Ivan Bièche, Christophe Le Tourneau. Randomized phase II trial of pre-operative afatinib in non-metastatic head and neck squamous cell carcinoma patients: Identification of predictive biomarkers of response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1237.