FOLFIRI
Meaning of FOLFIRI: A three-drug infusion schedule for advanced bowel cancer, its name assembled from the folinic acid and irinotecan it contains.
Definition of FOLFIRI
FOLFIRI is an abbreviation for a chemotherapy combination of folinic acid, fluorouracil and irinotecan, given by infusion in repeated cycles for advanced colorectal cancer. Folinic acid is not itself an anticancer drug: it locks fluorouracil onto its target enzyme and makes that block far more effective. Irinotecan attacks dividing cells by an entirely separate route.
What does each part do?
| Letters | Drug | Role |
|---|---|---|
| FOL | Folinic acid | Strengthens the block that fluorouracil applies |
| F | Fluorouracil | Starves the cell of a building block DNA needs |
| IRI | Irinotecan | Traps the enzyme that untangles DNA during copying |
Why is folinic acid included?
Fluorouracil works by jamming an enzyme called thymidylate synthase, which manufactures one of the four letters of DNA. The block is unstable on its own and the drug tends to fall away. Folinic acid supplies a cofactor that clamps the drug, the enzyme and the cofactor into a stable three-part complex, so the block holds much longer. It is a modulator rather than a chemotherapy agent, and given alone it has no effect on a tumor.
How is it given?
Treatment runs in cycles repeated every two weeks. Irinotecan and folinic acid are infused first, then part of the fluorouracil is given as a rapid injection and the rest slowly over roughly two days through a portable pump. Because that requires reliable venous access over months, a central line or an implanted port is usually placed. The slow infusion matters: fluorouracil is more effective against colorectal cancer when the exposure is prolonged rather than concentrated into a moment.
How does it compare with FOLFOX?
FOLFOX keeps the folinic acid and fluorouracil and replaces irinotecan with oxaliplatin. The two regimens perform similarly against advanced bowel cancer, so the choice often rests on which side effects suit the situation. Irinotecan is more associated with diarrhea, cramping and hair loss, and it can cause a sudden burst of sweating and gut cramping during the infusion itself. Oxaliplatin instead damages nerves, producing tingling in the hands and feet that is triggered by cold and can persist. Either can be combined with an antibody directed at the tumor blood supply or at a growth receptor.
Also known as
Used in a sentence
The plan was to proceed with FOLFIRI following progression on the first-line regimen.
Good to know
Folinic acid in this regimen is a modulator that strengthens the action of fluorouracil rather than an anticancer drug in its own right.