What is "tipifarnib"

n. A farnesyltransferase inhibitor with possible anticancer applications.

Tipifarnib (trade name Zarnestra) is a farnesyltransferase inhibitor that is being investigated in patients 65 years of age and older with newly diagnosed acute myeloid leukemia (AML). It inhibits the Ras kinase in a post translational modification step before the kinase pathway becomes hyperactive. It inhibits prenylation of the CxxX tail motif, which allows Ras to bind to the membrane where it is active. Without this step the protein cannot function.

It is also being tested in clinical trials in patients in certain stages of breast cancer.

For treatment of progressive plexiform neurofibromas associated with Neurofibromatosis type I, it successfully passed phase one clinical trials but was suspended (NCT00029354) in phase two. The compound was discovered by and is under investigation by Johnson & Johnson Pharmaceutical Research & Development, L.L.C, with registration number R115777.