Effects of treatment with octreotide in acromegalic patients - a multicenter Italian study

Treatment of acromegaly is effective in reversing the reduced life-span of patients only when serum growth hormone (GH) concentrations are lowered to less than 2.5 μg/l. Usual treatments achieve this goal in no more than 50-60% of patients, The effects of octreotide were studied in a prospective, open label study with 68 acromegalic patients enrolled in 10 Italian centers. Octreotide was administered sc at a dose of 100 μg t.i.d, for 1 year. After 3 months of therapy, octreotide was effective in decreasing serum GH levels below 2.5 μg/l in 16 out of 64 acromegalic patients (25%). Fifteen of them had pretreatment GH levels below 25 μg/l. Insulin-like growth factor I (IGF-I) levels normalized in about 40% of patients. No further GH reduction was observed after 1 year of treatment, The presence of abnormal GH responses to thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone was reduced from 54 to 24% and from 16 to 12%, respectively. Tumor shrinkage was observed in 50% of 26 non-irradiated patients after 12 months of treatment. Both basal and TRH-stimulated serum prolactin levels significantly decreased in the 11 hyperprolactinemic patients. Although serum thyrotropin, free triiodothyronine and free thyroxine concentrations were not modified, a significant reduction of thyrotropin response to TRH was observed in the 9th month of therapy. In non-diabetic patients, an increase of mean blood glucose levels without modifications of fasting morning concentrations was found. About one-quarter of the patients with overt diabetes mellitus had an impairment of their metabolic control. Main clinical symptoms of acromegaly improved in 70-80% of patients. An 18% decrease of low-density-lipoprotein cholesterol and unchanged high-density-lipoprotein cholesterol levels were observed in 35 patients studied. Triglyceride levels decreased in patients with hypertriglyceridemia pretreatment. Regarding side effects, gallstones were newly diagnosed in live patients, three patients dropped out because of severe diarrhea and two diabetic patients dropped out due to worsening of their metabolic control. In conclusion, octreotide is an effective treatment of acromegaly, mainly in patients with moderate elevation of serum GH levels, The drug has also been proved to positively affect dyslipidemia.