A phase II randomized study of combined infusional leucovorin sodium and 5- FU versus the leucovorin calcium followed by 5-FU both in combination with irinotecan or oxaliplatin in patients with metastatic colorectal cancer.

Leucovorin Sodium (LV/Na) has a high solubility, and is stable when given with continuous infusion of 5-FU. It could maintain significant plasma concentration of 5, 10-meTHF during the whole 5-FU perfusion with the potential of increasing 5-FU cytotoxicity. We conducted a randomized phase II clinical trial on leucovorin calcium (LV/Ca) and LV/Na in metastatic colorectal cancer patients (mCRC). Main objectives were to assess efficacy and safety.Fifty seven patients with mCRC and no previous chemotherapy for metastatic disease were randomized to receive LV/Na or LV/Ca with irinotecan or oxaliplatine combined with infusional 5-FU. LV/Na was defined as warranting further evaluation in phase III if true overall response rate (ORR) > 35% (α=5%, β=10% in case of true ORR >55%, 51 evaluable patients planned/arm).Results for LV/Ca and LV/Na arm respectively were: observed ORR, 55% (significantly higher than 35%, p = 0.02) and 61% (p = 0.004). Median overall survival durations were 11.9 months and 22.9 months (p = 0.02) and PFS 8.0 vs. 11.5 months (ns). Grade 3 events were 64% and 46% (p = 0.28).Both LV/Na and LV/Ca disclosed an ORR > 35% with comparable safety.