'Zoladex' versus 'Zoladex' plus flutamide in the treatment of advanced prostate cancer. First interim analysis of an international trial. International Prostate Cancer Study Group.

The first interim report of this multicentre prospective clinical trial to compare the efficacy of 'Zoladex' versus 'Zoladex' + flutamide in the treatment of advanced carcinoma of the prostate furnishes evidence of a reduction of the incidence of tumour flare within the first 4 weeks of therapy. The combination of 'Zoladex' and flutamide produced an earlier response in tumour markers (TAP, PAP) only. The combination, however, had no effect on subjective and objective response rates and had a negative effect on time to treatment failure. Flutamide produces a significant increase in toxicity and withdrawals due to toxicity. This interim analysis indicates that the continued administration of flutamide in combination with 'Zoladex' has no significant clinical benefit over that of 'Zoladex' alone. Further follow-up is required to determine whether combination treatment has any effect on time to treatment failure and survival.