Irinotecan, sold
under its trade name Camptosar®, is a semi-synthetic, water-soluble
derivative of camptothecin, which is a cytotoxic alkaloid extracted
from plants. Irinotecan and its active metabolite, SN-38, inhibits
the activity of topoisomerase I, an enzyme that produces reversible
single-strand breaks in DNA during DNA replication. Although primarily
used in the treatment of colorectal cancer, it is prescribed for
cancer of the cervix, esophagus, stomach, lung and pancreas. Irinotecan
is toxic, resulting in side effects such as severe diarrhea, anemia,
leukopenia, anorexia, nausea, fever, fatigue and abdominal pain.
Its patent expires in April 2005.
