Levoleucovori (Fusilev, Khapzory)

Description

Levoleucovorin is the active L-isomer of leucovorin, a folate analog used as a chemotherapy modulator in colorectal cancer treatment. It serves as a rescue agent to reduce toxicity from high-dose methotrexate and as a potentiating agent when combined with fluoropyrimidines like 5-fluorouracil (5-FU) in regimens such as mFOLFOX6. Levoleucovorin enhances the cytotoxic effects of 5-FU by stabilizing the inhibitory complex between 5-FU metabolites and thymidylate synthase. In colorectal cancer, it is routinely incorporated into combination chemotherapy protocols for both adjuvant and metastatic disease settings.

Mechanism of Action

Levoleucovorin is converted intracellularly to 5,10-methylenetetrahydrofolate, which serves as a cofactor that stabilizes the covalent binding of fluorodeoxyuridine monophosphate (FdUMP) to thymidylate synthase. This enhanced binding prolongs the inhibition of thymidylate synthase, the enzyme responsible for converting deoxyuridine monophosphate to deoxythymidine monophosphate, thereby blocking DNA synthesis and repair. The result is potentiation of 5-FU's cytotoxic activity against rapidly dividing cancer cells.

Side Effects

Not all side effects are listed. Side effects vary by individual. Always consult your oncologist.

Clinical Trials