Summary
Somatostatin (SRIF) is effective in the non-operative management of a variety endocrine
tumors. A potential role of SRIF for treatment of patients with primary hyperparathyroidism
(pHPT) has been suggested. In a controlled, prospective, triple-blinde, randomized
clinical trial, the somatostatin analogue octreotide (SMS 201-995, Sandostatin®) was evaluated in 40 patients with well documented pHPT. Amongst the biochemical
parameters, serum calcium and phosphate and levels of parathyroid hormone, calcitonin,
and osteocalcin as well as octreotide were assessed before and for 4 hours after a
single iv. application of 200 µg octreotide or placebo. SRIF-receptor autoradiography
was performed in parathyroid tissue samples.
Baseline values revealed a constellation of biochemical parameters typically found
in pHPT. Following 200 µg octreotide, no significant changes in any of the biochemical
parameters investigated for were observed. Multivariate analysis was performed to
identify patient subpopulations in which any given combination of laboratory parameters
changed in response to either drug or placebo. However, no ‘responders’ to octreotide
were identified. 45% of patients receiving octreotide, reported side effects. Parathyroid
tissue samples were negative for SRIF-receptor expression.
It is concluded that a single dose iv. application of octreotide does not result in
appreciable changes of biochemical parameters relevant in pHPT and carries a high
rate of side effects. Furthermore, absence of SRIF-receptors in parathyroid tissue
from patients with pHPT, together with lack of octreotide effects, suggests that somatostatin-analogues
may not be effective in the non-operative therapy of pHPT.
Key words
Somatostatin - primary hyperparathyroidism - controlled clinical trial
