Phase 1 study of RM-1929 photoimmunotherapy in Japanese patients with recurrent head and neck squamous cell carcinoma

Abstract

Abstract INTRODUCTION Photoimmunotherapy (PIT) is a novel cancer-targeted platform technology that utilizes monoclonal antibodies conjugated to a dye that can be activated with 690 nm nonthermal red light. PIT using RM-1929, consisting of the EGFR-directed monoclonal antibody cetuximab conjugated to a dye (IRDye 700DX), demonstrated promising clinical activity with overall response rate of 44.8%, median PFS of 5.7 months and median OS of 9.5 months in patients with recurrent head and neck squamous cell carcinoma (rHNSCC) in a phase 2a study with 30 patients (Gillenwater, ASCO 2018). METHODS The objectives of this phase 1 single-center, open-label, study were to evaluate the safety and objective response with RM-1929 PIT in Japanese patients with rHNSCC, who in the opinion of their physician, could not be satisfactorily treated with surgery, radiation, or platinum-based chemotherapy. Patients received a single fixed dose of RM-1929 (640 mg/m2) followed by tumor illumination with nonthermal red light, 24 hours after RM-1929 administration. Primary endpoint was safety of a single treatment of RM-1929 PIT. RESULTS Three female patients were enrolled in the study and received RM-1929 PIT. Median age was 68 (53-74). All patients failed more than 3 lines of prior therapy. Tumor sites included gums, temporal and cervical lymph nodes. All patients experienced edema and pain at the light application site. A Grade 3 application site pain treatment-emergent adverse event occurred in one patient. There were no serious adverse events, treatment discontinuation, or treatment-related deaths. Objective response based on modified RECIST 1.1 by central leader was observed in 2 patients. CONCLUSION RM-1929 PIT was well tolerated in 3 Japanese patients with rHNSCC. Preliminary efficacy data showed promising activity, and further investigation of this novel therapeutic strategy is warranted in an ongoing phase 3 clinical trial (NCT02422979).