Randomized phase II trial of ficlatuzumab with or without cetuximab in pan-refractory, advanced head and neck squamous cell carcinoma (HNSCC).
Authors: Julie E. Bauman, Nabil F. Saba, Denise Roe, Jessica R. Bauman, John M. Kaczmar, Aarti K. Bhatia, Jameel Muzaffar, Ricklie Ann Julian, Steven Wang, Shethal Bearelly, Audrey Baker, Conor Ernst Steuer, Anshu Giri, Barbara Burtness, Sara Centuori, Carlos Caulin, Kathylynn Saboda, Stefanie Obara, Christine H. Chung
Journal: Journal of Clinical Oncology (2021)

6015 Background: Cetuximab (C), an anti-EGFR monoclonal antibody (mAb), is approved for advanced HNSCC but benefits a minority. Crosstalk between the EGFR and hepatocyte growth factor (HGF)/cMet pathways is a known resistance mechanism. HGF is also immunosuppressive within the tumor microenvironment. A Phase I study confirmed the safety of C and ficlatuzumab (F), an IgG1 anti-HGF mAb, with preliminary efficacy and biomarker data suggesting that dual pathway inhibition may overcome tumor-intrinsic or immune cetuximab resistance. Methods: The primary objective of this phase II randomized, non-comparative trial was to evaluate the efficacy of F (20 mg/kg every 2 wks), with or without C (500 mg/m 2 every 2 wks), in pan-refractory, advanced HNSCC. Eligibility criteria included recurrent/metastatic HNSCC, performance status (PS) 0-1, C resistance (defined as progression on or within 6 months of exposure), and resistance to or ineligibility for platinum and anti-PD1 mAb. Randomization was stratified by HPV status and center. The primary endpoint was median progression-free survival (mPFS). An arm was deemed worthy of further study if the lower bound of the 90% 1-sided confidence interval (CI) excluded the historical control of 2 months. Secondary objectives included overall response rate (ORR) in the overall and HPV-stratified populations. A Bayesian continuous monitoring rule for futility was applied. Results: 60 patients were randomized and 58 treated between Jan 2018 and Dec 2020 (27 to F; 33 to FC). Baseline characteristics were balanced across major prognostic variables including age, PS, HPV status, platinum resistance, and PD1 mAb exposure. Median time since prior cetuximab was 3.5 months (range 0-48 months). Grade ≥3 adverse events attributed to F included: pneumonitis (2); edema (3); diarrhea (1); LFT elevation (1); rash (2); electrolyte abnormality (2). The Table presents efficacy data. The F arm stopped for futility after 26 evaluable subjects accrued. The FC arm completed accrual and met the primary endpoint; 32 evaluable subjects had mPFS of 3.6 months (lower bound 90% 1-sided CI: 2.3 months) and ORR of 19% (6/32). All responses were in HPV- subjects, including 2 complete (CR) and 4 partial responses (PR) to the FC combination and 1 PR to F monotherapy. The mPFS and ORR for the HPV- population (n = 16) on FC were 3.8 months and 38% (6/16). Mechanistic signaling and immune biomarkers are under analysis. Conclusions: The well-tolerated FC combination met the primary PFS endpoint in pan-refractory, advanced HNSCC with notable activity in HPV- HNSCC, warranting phase III investigation. Clinical trial information: NCT03422536. [Table: see text]