SAT-435 Optimization of Pharmacological Treatment of Acromegaly: Impact on IGF-1 Levels Comparing Isolated Octreotide LAR and Combined Pharmacological Therapy

Abstract

Background:Transphenoidal surgery remains the best treatment for acromegaly, although the disease is unlikely to be controlled with surgery in approximately half of macroadenomas. Unfortunately, invasive macroadenomas represents over than 65% of GH-secreting adenomas (1-4). Somatostatin analogues (SSAs) are widely recognized as the first choice of primary and postsurgical pharmacological therapy in patients with acromegaly. However, more than one third of the patients fail to control insulin-like growth factor I (IGF-I) and growth hormone (GH) levels. Previous studies have shown benefits arising from the combination of SSAs, cabergoline and even estrogen therapy in mild activity of disease. Objectives:The aim of this study was to compare the efficacy in decrease and normalization of IGF-I values, of Octreotide LAR treatment isolated compared to associated with cabergoline and or cabergoline and estrogen in patients that have not undergone any other pharmacological treatment. Patients and Methods: Case series studythat enrolled 54 patients, divided in two groups, receiving OCT-LAR initially administrated a dose of 20 mg/month (IM), adjusted individually, after 3 months, with the goal of achieving normal age-matched IGF-I values, reaching the maximum dose of 30 mg/month. The second group received OC-LAR 30 mg/month associated with CBG 2 mg per week.The third group received in combination estrogen therapy Results and Discussion:The baseline mean serum IGF-I was significantly higher than after 6 months of treatment with OCT-LAR (p=0,020) and OCT-LAR+CBG (p=0,004) but no significant difference was shown for the comparison of IGF-I after 6 and 12 months in OC-LAR group (p=0,960) or OC-LAR+CBG group (p=0,929). After de adjustment of IGF-1 levels for age, the data showed a significant reduction in ULNV% comparing the basal and 6 months values in OCT-LAR (p=0,013) and OCT-LAR+CBG (p=0,004). In group OCT-LAR, the best reduction of IGF-1 was obtained after 12 months of treatment. In the group OCT-LAR-CBG, the best control was achieved at six months and was not statistically different from 12 months (p=0,047). In multitreated patients, estrogen therapy benefited IGF-1 reduction. Conclusion: The percentage of patients that reached normalization of serum IGF-I was significantly higher in the OC-LAR + CBG group at 6 months. There was no statistically significant difference at 12 months post treatment .