Paclitaxel. An update of its use in the treatment of metastatic breast cancer and ovarian and other gynaecological cancers.

The antitumour agent paclitaxel has proved to be effective for the treatment of patients with metastatic breast or ovarian cancer, and limited data also indicate its clinical potential in patients with cervical or endometrial cancer. The regimen of paclitaxel administration has varied in clinical trials, the most common including a dosage of between 135 and 250 mg/m2 administered over an infusion period of 3 or 24 hours once every 3 weeks. Promising results have been achieved in phase I/II trials of a weekly regimen of paclitaxel (60 to 175 mg/m2). The objective response rate in patients with metastatic breast cancer (either pretreated or chemotherapy-naive) is generally between 20 and 35% with paclitaxel monotherapy, which compares well with that of other current treatment options including the anthracycline doxorubicin. Combination therapy with paclitaxel plus doxorubicin appears superior to treatment with either agent alone in terms of objective response rate and median duration of response. However, whether combination therapy also provides a survival advantage remains unclear; recent results of a phase III study indicate that it does not. Paclitaxel is also a useful second-line option in some patients with anthracycline-resistant disease. Combination therapy with paclitaxel and cisplatin has proved highly effective as first-line therapy for patients with advanced ovarian cancer, showing superior efficacy to cyclophosphamide/cisplatin in terms of progression-free survival time and median duration of survival. Combination therapy with paclitaxel and carboplatin has also shown promising results. Paclitaxel monotherapy is a useful second-line option for patients with platinum-refractory metastatic ovarian cancer (objective response rates have ranged from 15 to 48%). The major dose-limiting adverse events associated with paclitaxel include myelotoxicity and peripheral neuropathy. Paclitaxel has acceptable tolerability in most patients, although adverse events are common. Paclitaxel generally appears to be as effective as other antineoplastic agents used in the treatment of metastatic breast cancer, including doxorubicin. Importantly, it is a useful second-line option for some patients with anthracycline-resistant disease. Combination therapy with both paclitaxel and doxorubicin is a highly effective first-line option for metastatic breast cancer; however, recent results indicate no survival advantage versus monotherapy. Paclitaxel is a valuable agent for second-line treatment of patients with platinum-refractory metastatic ovarian cancer and, when combined with cisplatin or carboplatin, is recommended as first-line therapy for this disease.