First-line single-agent panitumumab in frail elderly patients with wild-type RAS unresectable colorectal cancer: a phase II study protocol OGSG 1602

BACKGROUND: A cytotoxic chemotherapeutic regimen is not routinely recommended for frail elderly patients with unresectable colorectal cancer (CRC) because of susceptibility to treatment. Panitumumab is a monoclonal antibody targeting the epidermal growth factor receptor (EGFR). Use of panitumumab as first-line therapy is expected to be well tolerated and to improve survival rates, even in patients who are not eligible for intensive chemotherapy. However, the efficacy and safety of panitumumab as the first-line therapy for the frail elderly patients with unresectable CRC have not been yet studied. METHODS: We plan to conduct a prospective multi-center phase II study. Patients with wild-type RAS unresectable CRC aged ≥76 years or ≥ 65 who are not considered eligible for intensive chemotherapy will be included in the study. A total of 36 patients will be enrolled from Osaka Gastrointestinal Cancer Chemotherapy Study Group for over 2 years. Panitumumab 6 mg/kg IV infusion will be administered every 2 weeks. The purpose of this trial is to assess the efficacy of panitumumab as first-line therapy for patients with unresectable CRC. The primary endpoint is to determine the disease control rate. Secondary endpoints include progression-free survival, overall survival, response rate, time to treatment failure, and the incidence of grade 3/4 toxicities. DISCUSSION: This is a prospective phase II trial assessing the efficacy of panitumumab monotherapy in the elderly patients with wild-type RAS unresectable CRC. TRIAL REGISTRATION: The ethics committee of the Osaka Medical College approved this study on November 7, 2016. The trial registration number of the government was UMIN000024528 on December 1, 2016. It was registered prospectively (the day of enrollment of the first participant was February 9, 2017).