A new longer-acting LHRH analog depot: preliminary results of a Dutch open phase II clinical study on a 10.8 mg Zoladex 3-monthly depot.

A new longer-acting depot formulation containing 10.8 mg Zoladex was administered subcutaneously without anesthetic to 35 patients with advanced carcinoma of the prostate. Pharmacodynamic and pharmacokinetic data show that following a transient elevation in serum LH and testosterone, the levels of both hormones decrease. Serum testosterone reaches the castrate range in all patients by week 4 and remains at this level for at least 12 weeks. The serum Zoladex profile shows that castrate serum testosterone values can be sustained by very low serum concentrations of the drug of around 0.05 ng/ml. In this preliminary report, the efficacy and safety of this new longer-acting 3-month depot formulation of 10.8 mg Zoladex has been shown to be comparable to the 1-month depot formulation of 3.6 mg Zoladex, in patients with advanced carcinoma of the prostate.