Shrinking of a Growth Hormone-Producing Pituitary Tumor by Continuous Subcutaneous Infusion of the Somatostatin Analog SMS 201-995

Abstract

SMS 201-995, a long-acting somatostatin analog, was given as the initial treatment to an acromegalic patient. SMS 201-995 (200 micrograms, sc, three times daily) reduced, but did not normalize, serum GH levels. Complete and prolonged control of GH secretion was obtained with a 600-micrograms daily continuous sc infusion (CSI), and the patient was treated in this way for 6 months. Rapid improvement of clinical signs and symptoms of acromegaly occurred, as did major tumor shrinkage. The other pituitary functions did not change. After 6 months, the daily SMS 201-995 dose was progressively reduced; GH secretion remained suppressed. After 12 months of treatment, GH secretion was controlled with a CSI of 100 micrograms SMS 201-995 daily, but not with two daily sc 100-micrograms injections. Further significant reduction in tumor size occurred. We conclude that CSI of SMS 201-995 resulted in constant GH normalization and marked clinical and morphological improvement. This form of treatment should be considered as an alternative to ablative treatment of acromegaly.

Effect of treatment with octreotide on the morphology of growth hormone—secreting pituitary adenomas: Study of 24 cases

“…Octreotide was given at a constant dose of 3 x t00 Ixg/day subcutaneously for 3 to 6 weeks before transsphenoidal surgery in 12 patients (group I, cases [1][2][3][4][5][6][7][8][9][10][11][12]. Twelve patients (group II, cases 13-24) were treated for 6 months before surgery.…”

Preoperative Treatment of Growth Hormone-Producing Pituitary Adenoma with Continuous Subcutaneous Infusion of Octreotide.

“…A few previous studies on continuous infusion with a variety of daily doses and periods [16][17][18] have not investigated the shrinkage of pituitary tumor with a small dose for a short duration as in our study. As in a previous report that octreotide induces a shrinkage of the tumor in approximately 50% of GH-producing tumors [6,7], a beneficial result was obtained in tumor shrinkage although we used small doses for a short duration with a continuous infusion pump.…”

“…In fact the optimal dose and duration of continuous infusions remain undetermined particularly with regard to the maximal effect on tumor size [16][17][18], although Barkan et al [8] suggested that octreotide therapy with intermittent injections seems to result in maximal effects within 8-12 weeks. Further control studies are required to establish the daily dose and duration of treatment with octreotide necessary to produce a satisfactory outcome [11,23].…”

“…Our practical regimen was designed with the purpose of reducing the daily dose and duration of treatment compared with the previous studies on continuous infusion [16][17][18]. Octreotide was infused at a dose of 5 ,ug/h in 6 patients (daily dose, 120 µg) or 10 µg/h in three patients (daily dose, 240 jig).…”

“…On the other hand, continuous infusion of octreotide has demonstrated more persistent suppression of GH secretion than intermittent injections [14,15], indicating that such a therapeutic regimen may allow a reduction in the total daily dose and the duration of treatment to produce tumor shrinkage, but only a few studies have been reported on the tumor shrinking effect with continuous infusion of a small dose of octreotide [15,16].…”