Clinical outcomes with therapies for previously treated recurrent/metastatic head-and-neck squamous cell carcinoma (R/M HNSCC): A systematic literature review

Objectives: A wide range of objective response rates (ORRs: 0-53%) among available treatments in patients with R/M HNSCC with progression on or after platinum-based chemotherapy (PBT) renders treatment selection a challenge. This systematic literature review (SLR) was intended to aid clinical decision-making by classifying historical studies to accurately characterize the response in second-line (progression on/after platinum-based therapy), and third-line (progression on/after platinum and cetuximab/other drug) settings.

Methods: SLR was performed to characterize the ORR, duration of response (DOR), progression-free survival (PFS) and overall survival (OS) with therapies recommended by the National Comprehensive Cancer Network (NCCN) guidelines. Clinical trials published in English between January 1, 1985, and September 30, 2016 were identified by searching the PubMed (Medline), Cochrane, and Embase databases.

Results: The SLR identified 34 key studies in second-line R/M HNSCC patients, and one of these included a third-line patient cohort. However, several studies did not enrol a strictly second-line population. Response in a true second-line setting was elucidated by categorizing the studies using a novel framework defined according to the extent to which enrolled patients were second-line. Only seven studies were strictly second-line, with an estimated pooled ORR of 4% (95% CI = 2-8%; N = 414) for methotrexate and 11% (95% CI = 7-15%; N = 235) for cetuximab, and a reported ORR of 14% (N = 78) from a single study of paclitaxel. The median DOR was limited with cetuximab (∼4 months) and paclitaxel (∼7 months), and not reported for methotrexate. Median PFS or time to progression (TTP) ranged from 1.7 to 3.5 months, and median OS from 4.3 to 6.7 months. The ORR in the only third-line study was 0% (95% CI = 0-7; N = 53) for the platinum + cetuximab combination.

Conclusion: These findings emphasize the historically bleak prognoses in patients with R/M HNSCC following PBT progression. Anti-PD-1 therapies, namely pembrolizumab and nivolumab, represent novel treatment options that may improve clinical outcomes.