Amivantamab in Recurrent/Metastatic Head and Neck Squamous Cell Cancer After Checkpoint Inhibitor and Chemotherapy: Pivotal Results From the Phase Ib/II OrigAMI-4 Study.

Single-agent paclitaxel or cetuximab after immune checkpoint inhibitor (ICI) and chemotherapy demonstrated objective response rates (ORRs) of 21%-24% in recurrent/metastatic (R/M) head/neck squamous cell cancer (HNSCC). Epidermal growth factor receptor (EGFR) and MET are overexpressed in R/M HNSCC. Amivantamab, an EGFR-MET bispecific antibody, may be a rational treatment. Cohort 1 of OrigAMI-4 (ClinicalTrials.gov identifier: NCT06385080) evaluated subcutaneous amivantamab administered every 3 weeks in participants with non-human papillomavirus R/M HNSCC after PD-(L)1 inhibitor and platinum-based chemotherapy. Prior anti-EGFR therapy and p16-positive oropharyngeal cancer were exclusionary. The primary end point was RECIST v1.1 ORR. Secondary end points included duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. In 102 participants, blinded independent central review‑assessed ORR was 42% (95% CI, 32 to 52); the complete response rate was 15%. Median DoR was not reached (NR; 95% CI, 6.9 to NR); 56% of responses lasted ≥6 months. Investigator-assessed ORR was 47% (95% CI, 37 to 57). At a median follow-up of 11.8 months (range, 1.1-21.9), median PFS and OS were 6.8 months (95% CI, 5.2 to 8.3) and 12.5 months (95% CI, 10.2 to 16.8), respectively. Adverse events were consistent with previous experience with no new safety signals. Treatment-related discontinuations were low (8%). Amivantamab demonstrated greater antitumor activity in participants previously exposed to ICI and chemotherapy than has been reported for paclitaxel or cetuximab.