Background: Pan added to combination chemotherapy is established first-line therapy for RAS and BRAF wild type mCRC. Elderly patients are not well represented in clinical trials and may be more suited to treatment protocols with lower toxicity risks; FU plus bevacizumab (bev) is commonly used. Treatment related efficacy, toxicity, impact on quality of life and other outcomes of pan based regimens in an elderly population have not been well studied. Methods: A prospective non-comparative randomized phase 2 study. Australian Clinical Trials Registry Number: ACTRN 12618000233224. Main inclusion criteria include: Untreated patients aged 70 years or older; RAS and BRAF wild type; ECOG performance 0-2. Randomisation 1:1, stratified by primary tumour side, performance status, number of metastatic sites; to pan 6mg/kg 2 weekly or panitumumab plus FU 400 mg/m² bolus; leucovorin 200mg/m²; FU 2400mg/m² 48 hour infusion 2 weekly. Primary endpoint is 6-month progression-free survival (PFS). Sample size is 80 patients based on expected 6-month PFS rate of 73% with FU and bev. Using the method of Metha-Cain, if 24 or more patients are progression free at 6 months, the one sided 95% confidence interval includes 73% and we declare similar activity. Secondary endpoints include overall survival; toxicity and overall treatment utility, a composite measure of treatment benefit based on radiology, clinical progress, toxicity and patient reflection of the impact of treatment on their daily lives. Patients undergo a comprehensive health assessment at baseline and limited health assessment at 4 months. Physical activity trackers are worn for 2 weeks at treatment commencement and again at week 16. Tumour tissue and blood samples (at baseline, cycle 3 day 1 and at 24 weeks) will be collected for translational research. First site opened in June 2018. Twelve patients have been recruited to date from 9 sites in Australasia. Eighteen sites were open as at September 2019. Clinical trial information: 12618000233224.