Four years' treatment of resistant acromegaly with octreotide

Abstract

McKnight JA, McCance, DR, Sheridan B, Atkinson AB. Four years' treatment of resistant acromegaly with octreotide. Eur J Endocrinol 1995;132:429–32. ISSN 0804–4643 This study was designed to ascertain the long-term safety and efficacy profile of the somatostatin analogue octreotide as treatment of refractory acromegaly. Eight patients (aged 21–62 years) with persistent growth hormone (GH) elevation (duration 1–15 years) despite previous therapy were studied. Octreotide was given subcutaneously in increasing doses for the first year to a maximum of 500 μg three times daily. The dose then was reduced to 200 μg three times daily for the next 3 years. At annual assessments, 24-h GH profiles, insulin-like growth factor I (IGF-I) and a side-effect profile including gall-bladder ultrasound were studied. Oral glucose tolerance tests (75 g) were performed basally and after 6 months and 3 years of therapy. Haemoglobin A1 (HbA1) was also assessed. Side effects were recorded. Mean GH (± sem) was 36.0 ± 9 mU/l basally and was reduced significantly at all subsequent assessments on therapy (4-year mean, 9.4 ± 2.1 mU/l). The IGF-I level also remained suppressed and was normalized in four of eight patients who remained on octreotide. Fasting plasma glucose and HbA1 were not changed by therapy but 2-h glucose was elevated after 6 months and 3 years (basal mean, 7.6 mmol/l (5.3–9.0 mmol/l); 3-year mean, 10.7 mmol/l (8.4–15.7 mmol/l); p < 0.05). Five patients developed gallstones and in three these had disappeared following 1 year of bile salt dissolution therapy. Octreotide continues to suppress serum GH and IGF-I long term without attenuation of effect. Gallstone formation is a major side effect. Two hours after glucose load the plasma glucose level was elevated but HbA1 did not change long term. Further similar studies of long duration are required to establish the long-term safety profile of the drug. AB Atkinson, Sir George E Clark Metabolic Unit, Royal Victoria Hospital, Belfast BT12 6BA, Northern Ireland