BERKELEY, CA (UroToday.com) - Degarelix, a GnRH antagonist, is a new prostate cancer therapeutic drug with a different mechanism of action from the existing drugs. It is likely to offer a new treatment option, in particular, to patients with symptomatic or metastatic prostate cancer who need a concomitant antiandrogen because degarelix does not cause a testosterone surge.
This Phase II study was conducted as a multicentre, randomized, parallel-group, open-label study. A total of 273 patients with adenocarcinoma of the prostate (any stage) were treated. Degarelix was administered subcutaneously at an initial dose of 240 mg followed by monthly maintenance doses of either 80 or 160 mg for a total of 12 doses. The treatment continued for 12 months.
Dose regimens of 240/80 and 240/160 mg maintained castrate levels of testosterone in 94.5 and 95.2% of the patients, respectively, with these levels without a testosterone surge. The best overall response rates according to RECIST in the patients with measurable lesions were 71.4 (20/28) and 72.7% (16/22). In addition, the overall response rate was assessed in all the patients based on “Assessment Criteria of Response to Noninvasive Treatment for Prostate Cancer (General Rule for Clinical and Pathological Studies on Prostate Cancer, (3rd edition))” that is commonly used for assessment of treatment effect in Japan. The overall response rates at week 12 showed high responses of 90.8% (119/131) at 240/80 mg and 90.5% (114/126) at 240/160 mg, and the response rates at week 52 were 84.5% (93/110) and 87.1% (88/101), respectively. According to the report by Akaza, et al.,[1] a GnRH agonist monotherapy showed overall response rate of 65.3% (66/101) at week 12, maximum androgen blockade (MAB), a combination therapy of an GnRH agonist in with an antiandrogen, 77.5% (79/102). Thus, Degarelix has a higher response rate than the GnRH agonist monotherapy and appears to have a comparable or higher response rate than MAB.
Based on the results from this Phase II study, the monthly degarelix regimen of 240/80 mg has been approved by the Ministry of Health, Labor and Welfare.
Reference:
- Akaza, et.al. Superior anti-tumor efficacy of bicalutamide 80 mg in combination with a luteinizing hormone-releasing hormone (LHRH) agonist versus LHRH agonist monotherapy as first-line treatment for advanced prostate cancer: interim results of a randomized study in Japanese patients. Jpn J Clin Oncol 2004; 34 (1) 20-28
Written by:
Seiichiro Ozono, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
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