Medline ® Abstract for Reference 23
of 'Chemotherapy in castration-resistant prostate cancer'
Adaptive therapy for androgen-independent prostate cancer: a randomized selection trial of four regimens.
Thall PF, Logothetis C, Pagliaro LC, Wen S, Brown MA, Williams D, Millikan RE
J Natl Cancer Inst. 2007;99(21):1613. Epub 2007 Oct 30.
BACKGROUND: Physicians typically switch therapies unless clinically relevant thresholds of response are observed, and treatments that produce high-quality responses and that are active in the salvage setting are generally felt to be promising. With the goal of efficiently selecting promising regimens for more advanced trials, we conducted a randomized selection trial of four regimens to identify promising treatments for androgen-independent prostate cancer.
METHODS: Patients without prior exposure to cytotoxic therapy were randomly assigned to one of four regimens (i.e., cyclophosphamide, vincristine, and dexamethasone [CVD]; ketoconazole plus doxorubicin alternating with vinblastine plus estramustine [KA/VE]; weekly paclitaxel, estramustine, and carboplatin [TEC]; paclitaxel, estramustine, and etoposide [TEE]). Patients were evaluated every 8 weeks to assess response and adverse events. Patients who responded continued with the same treatment; those who did not were randomly assigned to one of the other three treatments. Response was assessed by considering tumor-specific symptoms, tumor regression, and prostate-specific antigen (PSA) changes. Treatment was continued until two consecutive courses induced a response (i.e., overall success, the major criterion for which was 80% PSA reduction) or until patients were given two different regimens that failed to induce such a response.
RESULTS: Median overall survival from registration among all 150 patients was 22 months (95% confidence interval [CI]= 19 to 26 months). Estimated survival at 3 and 5 years, respectively, was 26% (95% CI = 20% to 35%) and 10% (95% CI = 5% to 16%). Overall success was achieved in 35 patients with the initial treatment (i.e., four treated with CVD, seven with KA/VE, 14 with TEC, and 10 with TEE) and in nine more patients with a second-line regimen (i.e., two with CVD, five with KA/VE, and two with TEC). For all 44 (29%, 95% CI = 23% to 37%) patients with overall success, median survival was 30 months (95% CI = 26 to 40 months); for the other 106 patients, it was 19 months (95% CI = 17 to 22 months). TEC produced the greatest number and proportion of successful courses of treatment, and TEC followed by KA/VE was the most promising two-stage strategy.
CONCLUSIONS: Some patients responded to particular treatments, and responses to second-line treatments were not rare. We propose that TEC be considered for phase III evaluation.
Department of Biostatistics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.