Docetaxel (sold under the brand name Taxotere) is a clinically well-established anti-mitotic chemotherapy medication (that is, it interferes with cell division). It is used mainly for the treatment of breast, ovarian, prostate, and non-small cell lung cancer. Docetaxel binds to microtubules reversibly with high affinity and has a maximum stoichiometry of 1 mole docetaxel per mole tubulin in microtubules. Docetaxel has been FDA-approved to treat patients who have locally advanced, or metastatic breast, or non-small-cell lung cancer who have undergone anthracycline-based chemotherapy and failed to stop cancer progression or relapsed. Docetaxel has a European approval for use in hormone-refractory prostate cancer. Docetaxel is a chemotherapeutic agent and is a cytotoxic compound. It is effectively a biologically damaging drug. As with all chemotherapy, adverse effects are common and many varying side-effects have been documented. Because docetaxel is a cell-cycle specific agent, it is cytotoxic to all dividing cells in the body. This includes tumour cells as well as hair follicles, bone marrow, and other germ cells. For this reason, common chemotherapy side effects such as alopecia occur (this can sometimes be permanent). The drug company Sanofi Aventis claims that they do not routinely keep this data. A survey being conducted in northwest France aims to establish exactly how many patients are being disfigured in this way. Independent studies show it could be as high as 6.3% which puts this ASE in the 'common and frequent' classification. Docetaxel is mainly metabolized in the liver by the cytochrome P450 CYP3A4 and CYP3A5 subfamilies of isoenzymes. Metabolism is principally oxidative and at the tert-butylpropionate side chain, resulting first in an alcohol docetaxel (M2), which is then cyclized to three further metabolites (M1, M3, and M4). M1 and M3 are two diastereomeric hydroxyoxazolidinones and M4 is an oxazolidinedione. Phase II trials of 577 patients showed that docetaxel clearance is related to body surface area and plasma levels of hepatic enzyme alpha-1-acid glycoprotein. Docetaxel is of the chemotherapy drug class taxane and is a semi-synthetic analogue of paclitaxel (Taxol), an extract from the bark of the rare Pacific yew tree Taxus brevifolia. Due to the scarcity of paclitaxel, extensive research was carried out which lead to the formulation of docetaxel, an esterified product of 10-deacetylbaccatin III. It was extracted from the renewable and readily available European yew tree. Drug interactions may be the result of altered pharmacokinetics or pharmacodynamics due to one of the drugs involved. Cisplatin, dexamethasone, doxorubicin, etoposide, and vinblastine are all potentially co-administered with docetaxel and did not modify docetaxel plasma binding in phase II studies. Cisplatin is known to have a complex interaction with some CYPs and has, in some events, been shown to reduce docetaxel clearance by up to 25%. Anticonvulsants induce some metabolic pathways relevant to docetaxel. CYP450 and CYP3A show increased expression in response to the use of anticonvulsants and the metabolism of docetaxel metabolite M4 is processed by these CYPs. A corresponding increase in clearance of M4 by 25% is observed in patients taking phenytoin and phenobarbital, common anticonvulsants. STAMPEDE is a UK-based six-arm, five-stage, open-label randomized controlled trial involving more than 3000 men. Arms C and E of this trial involve administering docetaxel to men starting long-term hormone therapy for the first time. This could be newly diagnosed metastatic, non-metastatic, or high-risk, previously-treated prostate cancer. The trial tests the value of the drug earlier in the treatment pathway instead of waiting until it has become androgen-independent.