Question
Vinca alkaloids
Answer
Vinca alkaloids are mitotic spindle inhibitors, cell-cycle-specific (M-phase) cytotoxic agents.
Examples: Vincristine, Vinblastine.
MOA: vinca alkaloid → binds tubulin → inhibits microtubule polymerization → prevents mitotic spindle formation → arrests cells in metaphase → mitotic cell death (a mechanism opposite to the taxanes, which stabilize microtubules and prevent their disassembly instead).
Uses: leukemias, lymphomas (vincristine, part of standard combination regimens such as CHOP), solid tumors (vinblastine — testicular cancer, Hodgkin lymphoma).
Adverse effects: vincristine — peripheral neuropathy (dose-limiting, distinctive among chemotherapy agents, since it causes comparatively little myelosuppression); vinblastine — myelosuppression is more prominent, with less neurotoxicity. Both cause vesicant tissue injury if extravasated.