Background: Oxaliplatin (OXA), is approved in combination with 5-FU/FA (5-fluorouracil/folinic acid; FOLFOX) for metastatic as well as in adjuvant colo-rectal cancer (CRC) treatment. CIPN is a common adverse event, after OXA treatment. The incidence of chronic CIPN is approximately 15% after a cumulative dose of 780 to 850 mg/m² and 50% after a cumulative dose of 1170 mg/m². OXA induced neuropathy, results in greatly reduced nitrated manganese superoxide dismutase (MnSOD) activity. Treatment with a superoxide dismutase mimetic, such as calmangafodipir (CAL), prevents and reverses oxaliplatin-induced neuropathies. This has been demonstrated in the PLIANT study, with CAL (Glimelius et al. 2017). Methods: The POLAR program is a Phase 3, multicenter, placebo (PLC)-controlled program of CAL to prevent CIPN, recruiting in US, Europe (B, D, ES, F,ES, I and UK) and Asia (J, SK, TW and HK) and is described below; POLAR A Patients with CRC, treatment of patients with Stage III or high-risk Stage II who are indicated for adjuvant modified FOLFOX6 (mFOLFOX6) chemotherapy for up to 6 months, randomized in a 1:1 ratio, each arm n = 140: A: CAL (5 µmol/kg) + mFOLFOX6 chemotherapy B: PLC + mFOLFOX6 chemotherapy POLAR M Patients with metastatic colorectal cancer (mCRC), who are indicated for first-line mFOLFOX6 chemotherapy for at least 3 months, without any pre-planned treatment breaks and will be randomized in a 1:1:1 ratio, each arm n = 140: A: CAL (2 µmol/kg) + mFOLFOX6 chemotherapy B: CAL (5 µmol/kg) + mFOLFOX6 chemotherapy C: PLC + mFOLFOX6 chemotherapy Primary objective is to compare CAL vs PLC with respect to the proportion of patients with moderate or severe chronic CIPN. The primary endpoint is; Patient reported symptoms as proportion of patients scoring 3 or 4 in at least 1 of the first 4 items of the FACT/GOG-NTX-13 (i.e., FACT/GOG-NTX-4), targeting numbness, tingling or discomfort in hands and/or feet, assessed 9 months after the first dose of chemotherapy. In addition to conventional safety endpoints, Progressive Free Survival and Overall Survival are assessed in the POLAR M study. In the POLAR A study Disease Free Survival is one additional safety endpoint assessed. Results are expected during second half 2020. Clinical trial information: NCT03654729