Current and future perspectives in advanced bladder cancer: is there a new standard?

Abstract

The methotrexate/vinblastine/doxorubicin/cisplatin (MVAC) regimen has been the standard treatment in patients with locally advanced and metastatic urothelial cancer for the past 15 years. The minimal or moderate survival benefit-depending on prognostic features-and the severe toxicity associated with the MVAC regimen have made the search for new drugs and drug combinations of utmost importance to increase efficacy and/or decrease toxicity. In this respect, the taxanes and gemcitabine are promising new drugs. Paclitaxel and docetaxel as single agents have yielded overall response rates of 7% to 56%, depending on whether the patients have received prior chemotherapy for metastatic disease. The combination of paclitaxel and cisplatin has been explored in three studies with a total of 104 evaluable patients, a pooled overall response (OR) rate of 61%, and a complete response (CR) rate of 20%. There are two studies of docetaxel and cisplatin with a total of 91 evaluable patients, an OR rate of 54%, and a CR rate of 16%. The OR rate for paclitaxel and carboplatin in six studies was 43%, with a CR rate of 13%; however, the reported median survival was only 8.5 to 9.5 months. The OR rate for single-agent gemcitabine based on five studies was 26%, with a CR rate of 9%, which was apparently independent of whether the patients had received prior chemotherapy. The OR rate for gemcitabine and cisplatin in four phase II studies ranged from 41% to 57%, with a CR rate of 15% to 22% and a median survival of 12.5 to 14.3 months. Based on the encouraging results for the combination of gemcitabine and cisplatin (GC), a randomized phase III trial comparing GC and MVAC was begun in late 1996. This study of 405 randomized patients showed that the two regimens were associated with similar response rates, time to progression, and overall survival, whereas GC was associated with less toxicity than MVAC. On the basis of this superior risk-benefit ratio, the GC regimen should be favored as a new standard treatment in patients with locally advanced and metastatic urothelial cancer. Other promising combinations include gemcitabine and paclitaxel, with or without cisplatin, and the combination of ifosfamide, paclitaxel, and cisplatin. The triple combination of gemcitabine, paclitaxel, and cisplatin has yielded an OR rate of 78%, a CR rate of 28%, and a median survival of 24 months. An international phase III trial comparing this triple combination with GC in patients with locally advanced and metastatic urothelial cancer has now been initiated.