Endocrine Abstracts

Background: It has been reported that primary treatment with somatostatin analogues (SSA) is effective in up to 60% of acromegaly patients, but predictive value of the acute octreotide suppression test (OST) for selection of patients with good response to depot SSA in long term treatment remains controversial.

Patients and methods: Twelve medical therapy naive patients (mean age 44 years, female 75%) with active acromegaly were included in prospective study. After administration of 100 μg octreotide the baseline and hourly GH measurements were taken for following 6 hours. GH response to the OST was defined as the percent reduction of GH from the baseline. Subsequently 6 patients received the long-acting SSA lanreotide (Somatuline Autogel), 120 mg every 28 days and 6 patients received long-acting SSA octreotide (Sandostatin LAR) 20–40 mg every 28 days for 3–24 month treatment period. GH and IGF1 were measured at baseline and during the treatment period.

Results: Fifty-eight percent of patients (7 out of 12) showed good response (>50% GH decrease) during the OST. 42% of them (3/7) reached target GH<2 ng/ml during the subsequent SSA therapy and only one patient (14%) achieved normalization of IGF1. 25% of patients (3 out of 12) showed moderate 30–50% GH decrease during the OST and only one reached normal IGF1 after administration of long-acting SSA. Despite that 17% of patients (2 out of 12) had only small <30% GH decrease during the OST, they reached the treatment target (GH<2 ng/ml) during the subsequent depot SSA therapy.

Conclusion: Acute OST has poor predictive value for effectiveness of subsequent long-acting SSA therapy and should not replace at least 3 month trial with depot SSA.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.