The effects of a very prolonged treatment with octreotide (OC)-long-acting repeatable (LAR) were retrospectively evaluated in 110 patients with acromegaly, showing a GH/IGF-I decrease of at least 20% vs. baseline after a short-term (6-month) OC-LAR challenge. OC-LAR was given (20 mg, im, every 28 d for 3 injections, then individually tailored) as adjuvant treatment (AT) in 59. The other 51 [primary treatment (PT)] were naive or previously treated by pharmacotherapy. IGF-I normalized in 83 patients [75%; from 770 ± 26 (mean ± SE) to 276 ± 15 μg]liter; P <0.0001; median follow-up, 30 months; range, 18-54 months). A progressive increase in the rate of IGF-I normalization was observed. GH fell to less than 2.5 μg]liter in 72% and to less than 1 μg]liter in 27% (from 20.7 ± 2.4 to 2.2 ± 0.2 μg]liter; P <0.0001). PT and AT patients achieved similar final GH/IGF-I levels and rates of normalization. Patients attaining safe GH and normal IGF-I had GH levels below 5 μg]liter after 3 months and IGF-I levels below 550 μg]liter after 6 months. No tachyphylaxis was observed. The up-titration to 30 mg improved IGF-I suppression. Elderly patients had greater sensitivity. Tumor shrank in 46% of assessable patients, in 77% of PT patients, and in 91% of naive patients. The powerful suppression of GH/IGF-I levels without tachyphylaxis, the finding of progressive increase in the rate of IGF-I normalization and of superimposable effects in PT and AT patients, and the predictive value of short-term results support the role of PT of acromegaly with OC-LAR in at least some patients.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism