Drug treatment for acromegaly: results of long-term use of Sandostatin LAR

Abstract

То evaluate the effectiveness and safety of drug treatment for acromegaly, the authors conducted an open-labeled prospective study of the impact of treatment with long-acting octreotide Sandostatm LAR) on the content of growth hormone (GH) and IRF-1 and on the size of a pituitary tumor. The study covered 40 patients (28 females and 12 males) aged 21 to 65 years (median 45 years) who had active acromegaly; 4 (10%) patients were diagnosed as having pituitary microadenoma; 36 (90%) had pituitary macroadenoma. Twenty-four patients received no therapy; 16 patients had tumors after their ineffective removal. All the patients took Sandostatin LAR, 20 mg intramuscularly, once every 28 days. The mean duration of treatment was 8.25 months (range: 3 to 12 months). Clinical and hormonal parameters were estimated 3, 6, and 12 months of treatment. A treatment-induced decrease in GH and/or insulin-like growth factor 1 (ILGF-1) by at least 30% of their baseline values considered effective. The state of a tumor was evaluated by brain magnetic resonance imaging in 26 patients. Three month following Sandostatin LAR treatment, the median concentration of GH significantly decreased from 33.5 to 5.55 ng/ ml (p < 0.001) and later on it remained nearly at this level (5.1 ng/ml and 5.35 ng/ml after 6 and 12 months, respectively). The concentrations of ILGF -1 similarly changed: its median was 779 ng/ml at baseline, 390 (p < 0.001), 390, and 330 ng/ml after 3, 6, and 12 months, respectively. Following 12 months of treatment, there were reductions in GH levels in 52.2% of the patients (including a < 2.5-ng/ml reduction in 33.3% of the patients) in the concentration of ILGF-1 by more than 50% of the baseline values in 49.9% (including a complete ILGF-1 concentration normalization in 33.3%). Twelve months after treatment, there was a reduction in the size of a tumor in 38.4% of the patients (by an average of41.25±7.22% of the baseline volume) and its growth stabilization in 59.1%. The findings suggest that treatment with Sandostatin LAR in a dose of 20 mg Is an effective and safe treatment, leads to a significant reduction in the values of GH and IL GF-1 just 3 months after treatment, and controls hormonal secretion and tumor growth in most patients with acromegaly.