PRISM: Phase 2 trial with panitumumab monotherapy as second-line treatment in patients with recurrent or metastatic squamous cell carcinoma of the head and neck

Background Panitumumab Regimen In Second-line Monotherapy of Head and Neck Cancer (PRISM) trial evaluated the safety and efficacy of panitumumab as second-line monotherapy in patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). Methods This was an open-label, single-arm, multicenter trial that enrolled patients with progressive disease or intolerance to first-line systemic chemotherapy for recurrent or metastatic SCCHN. Patients received panitumumab 9 mg/kg Q3W. The primary endpoint was overall response rate; secondary endpoints included disease control rate, overall survival (OS), progression-free survival (PFS), and safety. Results The overall response rate was 4% (2 of 51 patients) and the disease control rate was 39% (20 of 51 patients). Median PFS was 1.4 months (95% confidence interval [CI] = 1.3-2.4 months). Median OS was 5.1 months (95% CI = 4.3-8.3 months). The most common adverse events were rash/dermatitis acneiform (69%), fatigue (33%), dry skin (21%), and hypomagnesemia (21%). There was one treatment-related death (angioedema). Conclusion Panitumumab monotherapy had limited activity in previously treated patients with recurrent or metastatic SCCHN.