The effect of a new ergoline derivative, CU 32-085, in the treatment of acromegaly. A controlled study.

The effect of a new dopamine agonist, CU 32-085 (8 alpha-amino-ergoline), on pituitary function in acromegaly was evaluated by a controlled, single blind study of 12 acromegalics. The study included a single dose placebo/drug (0.5 mg CU 32-085) trial and a long-term crossover trial with 3 month periods (placebo/CU 32-085 8 mg daily). The patients were evaluated clinically and biochemically (oral glucose tolerance (OGTT), TRH- and LHRH-tests) before and after each 3 month period. Nine patients completed this long-term trial; one died from myocardial infarction during the placebo period, and two dropped out because of side effects. The release of GH, judged from more than 9 h suppression of serum GH following the single dose, and from the response to OGTT after the long-term treatment, was significantly inhibited by CU 32-085. Serum GH reached normal values in 4 of 9 patients. Serum PRL was also markedly suppressed, to subnormal values after the 3 months in all but one hyperprolactinemic patient. Serum TSH, cortisol, FSH and LH were generally unaffected. Glucose tolerance was not significantly altered, although an improvement was found in six of nine patients. A semiquantitative evaluation of subjective symptoms showed a significant improvement following the long-term treatment, while objective signs of acromegaly were unaffected. The blood pressure was slightly lowered, both after a single dose and after 3 months' treatment. Seven patients experienced nausea and dizziness, two of them with vomiting, after a single dose of the drug. Four of these had similar symptoms initially during the long-term treatment, which forced two to interrupt the trial. We conclude that CU 32-085 caused a marked suppression of the release of GH and PRL and an improvement of the major symptoms of acromegaly, a therapeutic effect that is comparable to the previous experience with bromocriptine.