(067) Efficacy of Capecitabine as Second-Line and Later Therapy in Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma

Poster Abstract:

Background: Capecitabine is a NCCN category 2A recommendation for treatment of recurrent/metastatic (R/M) HNSCC in the second line or later setting. Data for capecitabine use in this setting is limited to two studies which have notable limitations including small sample size, differing dosing regimens, and no prior exposure to PD-1 inhibitors.

Objectives: This study aims to evaluate the real-world efficacy and tolerability of capecitabine for second line or later treatment of R/M HNSCC with key subgroup analyses.

Methods: This was a single center, retrospective review of adult patients with R/M HNSCC who were treated with capecitabine monotherapy after at least one prior line of systemic therapy from January 2015 to April 2023. Primary objective was disease control rate (DCR). Secondary endpoints included overall response rate (ORR), progression-free survival (PFS), and overall survival (OS).

Results: Preliminary results are included although survival analyses are pending. Thirty-seven patients were included. Thirty-two (86%) patients received prior PD-1 therapy with 30 (81%) patients receiving capecitabine in the third line or later setting. The DCR was 51%. Pre-specified subgroup analyses included DCR of prior PD-1 inhibitor therapy versus no prior PD-1 inhibitor use which was 47% vs 60% respectively. DCR for patients prescribed capecitabine in the second line setting was 86% versus 43% in third line or later setting. An ORR of 27% was observed with median duration of response (DOR) of 52 days. Dose interruptions occurred in 14% of patients and 22% required dose reductions, usually occurring after cycle 2 or 3.

Discussion: The results of this study were comparable with the results of two prior capecitabine studies in terms of DCR and ORR. Prior PD-1 therapy does not appear to have significant impact on DCR, however DCR is significantly lower in patients who receive treatment in 3rd line or later setting. Despite 51% DCR, this response is short-lived. Limitations include small sample size and uneven groups for the subgroup analyses.

Conclusions: Although well tolerated, capecitabine has limited use in R/M HNSCC particularly in 3rd line or later setting due to short DOR. Newer therapies are needed for patients who progress on standard 1st and 2nd line therapies.

References (must also be included in final poster): 1. Mody MD, Rocco JW, Yom SS, et al: Head and neck cancer. Lancet 2021;398:2289-2299.
2. Siegel RL, Miller KD, Fuchs HE, et al: Cancer statistics, 2022. CA Cancer J Clin 2022;72:7-33.
3. National Comprehensive Cancer Network. Head and Neck Cancers (Version. 1.2023). 2023. Available from: https://www.nccn.org/professionals/physician_gls/pdf/head-and-neck.pdf
4. Martinez-Trufero J, Isla D, Adansa JC, et al. Phase II study of capecitabine as palliative treatment for patients with recurrent and metastatic squamous head and neck cancer after previous platinum-based treatment.?Br J Cancer. 2010;102(12):1687-1691.
5. Péron J, Poupart M, Ceruse P, et al. Efficacy and safety of capecitabine in heavily pretreated recurrent/metastatic head and neck squamous cell carcinoma. Anticancer Drugs. 2012;23(10):1107-1111.