Investigation into the Efficacy and Safety of Octreotide LAR in Japanese Patients with Acromegaly: Shizuoka Study

Abstract

The efficacy and safety of the long-acting repeatable formulation of octreotide (OCT-LAR) treatment in patients suffering from acromegaly was investigated retrospectively in Shizuoka prefecture, Japan. Thirty patients (11 male, 19 female; average age, 48.9 years old), 29 of whom had undergone transsphenoidal surgery previously, were treated with OCT-LAR. OCT-LAR was injected i.m. every 4 weeks with an intended protocol of 20 mg over 24 months, however, 46.7% of patients required the dose of OCT-LAR to be increased. The final average dose of OCT-LAR was 25.0 ± 6.8 mg. Administering OCT-LAR significantly decreased serum GH and insulin-like growth factor 1 (IGF-1) levels (from 13.7 ± 11.9 to 5.8 ± 7.3 μg/L and from 585 ± 263 to 339 ± 193.7 μg/L after 3 months, respectively). Among patients treated with OCT-LAR, 56.7% expressed ≤2.5 μg/L serum GH and 53.3% displayed serum IGF-1 levels within the normal range, while 36.7% met both criteria that indicated treatment success. A sufficient outcome was achieved in 73.3% of patients when the rate of GH ≤2.5 μg/L or normalization of IGF-1 was accumulated. OCT-LAR did not have a negative effect on glucose tolerance when hemoglobin A1c was used as a marker. A gallbladder polyp was found only in 1 patient but it was uncertain whether OCT-LAR was involved in its development because the patient was not examined before OCT-LAR treatment. There were no abnormalities on liver function tests in any patients. In conclusion, our results showed that OCT-LAR was safe and effective as a therapeutic option for Japanese patients with acromegaly in a postoperative setting, by controlling the disease activity.