Weekly Paclitaxel, Carboplatin, and Cetuximab (PCC) as Treatment for Recurrent or Metastatic Head and Neck Squamous-cell Carcinoma (RM-HNSCC) that Progressed on Immune Checkpoint Inhibitors (ICI): A Retrospective Analysis

Purpose/Objective(s) Data is lacking regarding the best treatment option for patients (pts) with RM-HNSCC after progression on ICI. Weekly PCC has reduced toxicity compared with triweekly PCC. We report the outcomes of pts treated with weekly PCC after progression on ICI. Materials/Methods We analyzed pts with RM-HNSCC who received weekly PCC (paclitaxel 45 mg/m2, carboplatin area under the curve 1.5, cetuximab 400 mg/m2 first week, and 250 mg/m2 weekly thereafter) after progression on ICI between July 2016 and November 2022. We collected data on tumor site, P-16, combined positive score (CPS), overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). PFS was defined as the time from PCC initiation and disease progression or death. OS was defined as the time from PCC initiation and death. Results Of the 44 pts available for analysis, 84% were male, and the median age was 60 yrs (IQR: 53, 68). The most common tumor site was oropharynx (48%), followed by oral cavity (27%) and others (25%). Nineteen pts (43%) were initially treated with ICI-chemotherapy and 25 (57%) with ICI alone. The median duration of treatment with ICI was 5.1 months (mo) (IQR: 2.7, 10.6). CPS values were available in 33 pts: 0% (8 pts), 1-20% (10 pts), and 21-100% (15 pts). The median follow-up time for PFS and OS was 4 mo (IQR: 2.8) and 8 mo (IQR: 3, 11), respectively. ORR were as follows: partial, 16 (36%); stable, 12 (27%); and progression, 16 (37%). Median survival time for PFS and OS was 3.8 mo (95% CI: 2.5,5.6) and 9.2 mo (95% CI: 7.8, 14.4), respectively. In overall survival analysis, after adjusting for age, sex, P-16 status, and lymphocyte count, increased duration of treatment on ICI was associated with better OS (HR: 0.96, 95% CI: 0.88, 1.05, p=0.4). A separate model including CPS showed that CPS values of 1-20% and 21-100% had reduced hazard compared to CPS of 0% (HR: 0.24, 95% CI: 0.05, 1.31; HR: 0.06, 95% CI: 0.01, 0.58; respectively, LRT p=0.006). Conclusion Weekly PCC is an active treatment for RM-HNSCC pts that progressed on ICI. There is an association between positive CPS, longer duration of treatment on ICI, and increased OS.