Endocrine Abstracts

VA Thornton-Jones, JAH Wass and HE Turner, OBJECTIVE: Despite a recommended injection frequency of 4 weekly(4w), prolonged duration of GH suppression has been observed in some patients following treatment with long-acting somatostatin analogues. The aim of our study was to perform a prospective systematic study to determine whether extending the interval between doses of Octreotide LAR (LAR) allows maintenance of 'safe' GH in selected patients with acromegaly.

METHODS: 22 patients (15m), mean age 58.9y with active acromegaly received treatment with LAR. 11 patients had undergone trans-sphenoidal surgery (TSA) and radiotherapy, 6 TSA alone and 5 medical treatment only. All patients were commenced on LAR 20 mg 4w. Mean GH (mGH) was measured after 3 consecutive injections immediately prior to the fourth injection. The injection frequency was systematically reduced after every 4 injections if mGH <5 mU/l. Once mGH > 5 mU/l, the dose frequency was increased and GH reassessed to ensure mGH <5mU/l.

RESULTS: Dose interval was successfully increased to >4 weeks in 20/22 patients (90.9%). 5/22 (22.7%) were receiving injections every 8 weeks, and 3/22 (13.6%) every 12 weeks. GH and IGF-1 were lower on treatment compared with baseline (p<0.01) but there was no difference in individual mGH or IGF-1 after 4w dosing and at final dose frequency. There was no relationship between the final dose frequency and either mGH or IGF-1 prior to LAR treatment, patient age, or previous treatment. Acute GH suppression Octreotide s/c did not predict subsequent dose frequency of LAR. The overall drug cost if patients had continued at 4w injections would be £187 850 compared with £102 935 for the individually titrated dose frequency (p<0.01). This represents a final cost of 54.2% of the 4w injection price.

CONCLUSION: Individual patient tailoring of LAR administration maintains control of acromegaly with reduced injection frequency and improved cost-effectiveness.