Efficacy of concurrent cetuximab (CTX) and nivolumab (NIVO) in previously untreated recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC).

Abstract

6017 Background: Current standard of care for patients (pts) with previously untreated R/M HNSCC that are incurable is either pembrolizumab (pembro) with/without chemotherapy depending on the Programmed Death-Ligand 1 (PD-L1) combined positive score (CPS). We evaluated the combination of CTX and NIVO for its efficacy. Methods: Pts were treated with CTX 500 mg/m2 IV on Day (D) -14 as a lead-in followed by CTX 500 mg/m2 IV and NIVO 240 mg/m2 IV on D1 and D15 every 28-D cycle (C). Pts with CTX infusion reaction or who did not receive C1D1 for any reason were non-evaluable and replaced. NIVO dose reduction was not allowed. Results: Fifty-four evaluable pts were analyzed. Median age was 62 (42-85). ECOG performance status at baseline was 0 (20, 37%), 1 (30, 56%), and 2 (4, 7%). Primary sites were oral cavity 19 (35%), oropharynx 22 (41%), hypopharynx 3 (6%), larynx 9 (17%), and unknown primary 1 (2%). p16 status is positive 22 (41%), negative 29 (54%), and unknown 3 (6%). PD-L1 CPS is < 1 in 6 (11%), >1 in 26 (48%), and unknown 22 (41%). Median follow up time for overall survival (OS) was 12.2 months. The most common grade 3 treatment-related adverse events (TRAEs) occurring in ≥2 pts were hypomagnesemia 2 (4%), hypophosphatemia 2 (4%), fatigue 4 (7%), and rash-acneiform 4 (7%). The only grade 4 TRAEs were hypomagnesemia in 1 (2%) and CTX infusion reaction in 1 (2%). The most common grade 3 immune-related adverse event (IRAE) occurring in ≥2 was fatigue 2 (4%). No grade 4 IRAEs is observed. Median progression-free survival (PFS) and OS were 7.8 and 14.5 months, while 1-year PFS and 1-year OS were 39% and 61%, respectively. There were no statistically significant differences in either PFS and OS based on tumor p16 or PD-L1 status. Conclusions: The clinical trial met its primary endpoint of 1-year OS. Our data indicate the combination of CTX and NIVO is safe and effective in pts with previously untreated incurable R/M HNSCC. Clinical trial information: NCT03370276.