Plant Alkaloids
Vinblastine -- (Velban)
Mechanism of action: microtubule depolymerization
Mitotic arrest at metaphase; interferes with chromosome segregation
Clinical Use::
Systemic treatment of Hodgkin's disease
Lymphomas
Adverse Effects:
Nausea
Vomiting
Alopecia
Bone marrow suppression
Vincristine -- (Oncovin)
In combination with prednisone: induction of remission in children with acute leukemia
Useful in treating some other rapidly proliferating neoplasms
Significant frequency of neurotoxic reactions
Occasional: bone marrow depression
Podophyllotoxins (etoposide {VP- 16}and teniposide {VM-26})
Etoposide and teniposide: structurally similar
Mechanism of action: Block cell cycle: in late S-G2 phase
Inhibition of topoisomerase II -- DNA damage
IV administration
Urinary excretion; some in bile
Clinical Use:
Etoposide (VP-16,VePe-sid):
Monocytic leukemia
Testicular cancer
Small cell lung carcinoma
Teniposide (Vumon): lymphomas
Significant hematopoietic toxicity and lymphoid toxicity
Camptothecins (topotecan and irinotecan )
Mechanism of action: interfere with activity of topoisomerase I (cuts and religates single stranded DNA. DNA is damaged
Clinical Uses:
Topotecan: metastatic ovarian cancer -- including cisplatin-resistant forms (as effective as paclitaxel)
Adverse Effects: Topotecan --
Primary
Neutropenia
Thrombocytopenia
Anemia
Other
Irinotecan: prodrug-metabolized active topoisomerase I inhibitor
Used in management of colon and rectal cancer, including tumors not responding to 5-FU
Adverse Effects: Irinotecan --
Most common: diarrhea
Also common: nausea, vomiting
Dose limiting adverse effect: myelosuppression
Taxanes (Paclitaxel (Taxol) and Docetaxel (Taxotere))
Paclitaxel (Taxol): derivative of the Western Yew
Mitotic spindle inhibitor: enhances tubulin polymerization
Ovarian
Advanced breast cancer
Dose-limiting Adverse Effects:
Peripheral neuropathy
Docetaxel (Taxotere):Used in advanced breast cancer
Adverse Effects:bone marrow suppression
Salmon, S. E. and Sartorelli, A. C. Cancer Chemotherapy, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, p. 881-911.