Archives for: May 2005
Been reading about a new class of cancer chemotherapy drug, called the epothilones, which seem to offer the promise of greater efficacy, with perhaps a special relevance for blood group A cancer patients. The epothilones are much like the taxol class of chemotherapy drugs in that they inhibit mitotic spindle degradation in the malignant cell (mitotic spindles are the delicate network of tubes that act as a scaffold for the migration of the split chromosomes as the become two new â€˜daughter cells.' In essence, promoting tubulin polymerziation prevents the mitotic spindle from being broken down by stabilizing the microtubule bundles, so the cell cannot replicate.
Taxol class chemotherapy drugs represent one of the most effective classes of anticancer therapeutics; however many human cancers either do not respond or become resistant to taxol-based therapy. Since 1995 Epothilone B, a new drug class sharing the same mechanism as taxol, has been in development. But, unlike taxol type drugs, epothilones have cytotoxic activity on cells overexpressing P-glycoprotein. P glycoprotein is rewsponsible in part, for drug resistance associated with many anti-cancer treatments.
This may be important for type A individuals, who appear to have increased level of p-glycoprotein in their malignancies, which may explain why in my clinical observances, they tend to be under-represented in the long term survivor groups. A drug that does not appear to be inhibited by p-glycoprotein may be just what the patient ordered.
In contrast to taxol class drugs, epothilones demonstrate a 2.5-fold greater potency than taxol, cause virtually complete cell-cycle arrest and are active in a large panel of cell lines and multi drug-resistant cancer types.
Obviously, I'm not a big fan of chemotherapy. But, as of right now, it is a part of the cancer treatment landscape and if it can be made to work better in certain individuals, so much the better.