Weekly paclitaxel (P), carboplatin (CP) plus pembrolizumab (PMB) as first-line treatment of recurrent or metastatic (R/M) or locally very advanced (LVA) head and neck squamous cell carcinoma (HNSCC): A retrospective study in 39 patients (pts).

e18018 Background: Since the results of the KN-048 trial, the combination of platinum/5FU plus PMB has become the standard of care (SOC) for R/M HNSCC pts. The KN-B10 study shows that 5FU can be replaced by P with a favorable response rate and toxicity profile. Weekly use of P reduces hematologic toxicity and increases dose-intensity. Methods: We retrospectively reviewed all records of patients with R/M or LVA (T4b and/or N3b) HNSCC, ECOG-PS 0 to 2, PDL1 CPS ≥ 1, treated in first-line with weekly P (80 mg/m2) and CP (AUC 2: maximum total dose of 250 mg and systematic G-CSF at D3 and D4) for up to 12 infusions plus PMB every 3 weeks for up to 35 administrations. Results: From July 2020 to April 2023, 39 pts (median age 63 years, 74% male, 18% PS2) were treated. Primary tumors: oropharynx 44%, larynx 23%, hypopharynx 18% and oral cavity 15%. Disease setting: LVA 20%, local recurrence in irradiated area 54%, local recurrence and distant metastases 10% distant metastases only15%. With a median follow-up of 19 months (m), median Overall Survival (mOS) was 17.2 m (95%CI: 10.8-NR). 31/39 (79%) pts achieved an objective response (OR): 7 CR and 24 PR. For the 8 LVA pts, all achieved an OR, with a median Event Free Survival of 10 m (95%CI: 6.27-NR): the 4 progression-free pts (8.6 m+ to 25 m+) were treated with radiotherapy after neoadjuvant immuno-chemotherapy. For the 31 R/M pts, ECOG-PS was a significant prognostic factor of OS, mOS: 19.3 m (95%CI: 14.4-NR) for ECOG-PS 0-1 pts vs. 10.3 m (95%CI: 5.4-13.9) for ECOG-PS 2 pts (p = 0.02). For R/M pts, median Progression Free survival was 6.9 m (95%CI: 4.4-8.6) and the ORR was 74%, with a median duration of response of 6.5 m (95%CI: 3.13-8.56). Toxicity was manageable, with 20 (51%) pts experiencing at least one grade 3-4 adverse event: hematologic 18% (including one febrile neutropenia), infection 5%, neuropathy 8%, diarrhea 8%, infusion reaction 8%, electrolyte disturbances 8%, renal failure 3% and no toxic deaths. Conclusions: The combination of weekly P and CP plus PMB produces a high ORR and increased OS consistent with the results of the Frail-Immune study (J. Fayette ASCO 2023). This regimen deserves further consideration not only in the R/M setting, but also in the neoadjuvant setting for locally advanced patients.