AUTHOR=Seront Emmanuel , Schmitz Sandra , Papier Matthias , van Maanen Aline , Henry Stéphanie , Lonchay Christophe , Rottey Sylvie , van Caloen Gabrielle , Machiels Jean-Pascal 

TITLE=Phase 1 Study Evaluating the Association of the Cyclin-Dependent Kinase 4/6 Inhibitor Ribociclib and Cetuximab in Recurrent/Metastatic p16-Negative Squamous Cell Carcinoma of the Head and Neck

JOURNAL=Frontiers in Oncology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2019.00155

DOI=10.3389/fonc.2019.00155

ISSN=2234-943X

ABSTRACT=<p><bold>Background:</bold> The majority of human papillomavirus (HPV)-negative squamous cell carcinoma of the head and neck (SCCHN) present upregulation of the epidermal growth factor receptor (EGFR) and frequent alterations in the cyclin D1-cyclin dependent kinase (CDK) 4/6 (CDK 4/6)-retinoblastoma protein (pRb) pathway, resulting in cell cycle progression and tumor proliferation. This study investigated the combination of ribociclib, an orally highly selective inhibitor of CDK 4/6, and cetuximab in recurrent and/or metastatic (R/M) SCCHN.</p><p><bold>Methods:</bold> A phase I trial using a 3 + 3 design was performed to determine the dose limiting toxicity (DLT) and maximum tolerated dose (MTD) of ribociclib with standard dose of weekly cetuximab in HPV-negative patients with R/M SCCHN. Ribociclib was administered orally (3 weeks on/1 week off) at dose level 1 of 400 mg daily and dose level 2 of 600 mg daily. The MTD of ribocilib was then further evaluated in an expansion cohort.</p><p><bold>Results:</bold> 10 patients were enrolled in the escalation trial. No DLTs were observed at dose level 1 (<italic>n</italic> = 3); at dose level 2, one patient was replaced due to rapid disease progression, and one patient out of six evaluable patients experienced a DLT (grade 4 thrombocytopenia &gt;7 days). Ribociclib 600 mg daily was thus determined to be the MTD. Eleven additional patients were enrolled in the expansion cohort. Diarrhea (52%), rash (52%), fatigue (43%), nausea (33%), and mucositis (28%) were the most frequent grade 1–2 adverse events (AE). Neutropenia was the most frequent grade 3–4 AE (20%). Median progression-free survival (PFS) was 3.5 months (range 0.4–17.3 months) and median overall survival (OS) was 8.3 months (range 0.4–24.1 months). Among the 19 radiologically evaluable patients, two (10.5%) achieved a partial response and 11 (58%) had stable disease.</p><p><bold>Conclusions:</bold> The MTD of ribociclib is 600 mg daily when administered in combination with standard dose cetuximab for 3 weeks on and 1 week off. This combination was safe and showed efficacy. Further clinical trials should be conducted to evaluate the antitumor effects of this combination.</p><p><bold>Trial Information:</bold><ext-link ext-link-type="uri" xlink:href="https://clinicaltrials.gov/" xmlns:xlink="http://www.w3.org/1999/xlink">ClinicalTrials.gov</ext-link>: NCT02429089; Eudract number 2014-005371-83.</p>