First-line octreotide-LAR therapy induces tumour shrinkage and controls hormone excess in patients with acromegaly: results from an open, prospective, multicentre trial

• Published in: Clinical endocrinology (Oxford) Vol. 64; no. 3; pp. 342 - 351
• Main Authors: Colao, Annamaria, Pivonello, Rosario, Rosato, Francesca, Tita, Patrizia, De Menis, Ernesto, Barreca, Antonina, Ferrara, Roberto, Mainini, Franco, Arosio, Maura, Lombardi, Gaetano
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-2006; Blackwell
• Subjects: Acromegaly - drug therapy; Acromegaly - etiology; Acromegaly - pathology; Adenoma - complications; Adenoma - drug therapy; Adenoma - pathology; Adult; Antineoplastic Agents, Hormonal - therapeutic use; Biological and medical sciences; Delayed-Action Preparations; Endocrinopathies; Female; Fundamental and applied biological sciences. Psychology; Growth Hormone-Secreting Pituitary Adenoma - complications; Growth Hormone-Secreting Pituitary Adenoma - drug therapy; Growth Hormone-Secreting Pituitary Adenoma - pathology; Human Growth Hormone - blood; Humans; Hypothalamus. Hypophysis. Epiphysis (diseases); Insulin-Like Growth Factor I - analysis; Male; Medical sciences; Middle Aged; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Octreotide - adverse effects; Octreotide - therapeutic use; Prospective Studies; Treatment Outcome; Vertebrates: endocrinology; Endocrinopathy; Human; Multicenter study; Peptide hormone; Diseases of the osteoarticular system; Acromegaly; Octreotide; Shrinkage; Neuropeptide; First line treatment; Prospective; Analog; Pituitary diseases; Tumor; Somatostatin; Endocrinology
• ISSN: 0300-0664; 1365-2265
• DOI: 10.1111/j.1365-2265.2006.02467.x

Summary
Background  The majority of patients with acromegaly have large tumours and the outcome of conventional management remains poor.
Objective  To investigate the clinical application of octreotide‐LAR as primary treatment in newly diagnosed patients with GH‐secreting pituitary tumours.
Design  Open, prospective, multicentre, 24‐week follow‐up study.
Patients  Thirty‐four patients were enrolled (20 men, 14 women; mean age, 50 years); 13 had microadenoma [median tumour volume 327 mm3 (range 31–629 mm3)], 21 had macroadenoma [median tumour volume 1325 mm3 (range 503–11583 mm3)].
Interventions  Octreotide‐LAR at the dosage of 20 mg every 28 days for the first 12 weeks increased to 30 mg every 28 days to control GH and/or IGF‐I excess in 20 patients (64·7%).
Main outcome measures  Primary endpoints were control of GH (fasting < 2·5 µg/l) and IGF‐I secretion (gender‐ and age‐normalized) and presence and entity of tumour mass shrinkage. Secondary endpoint was improvement of symptoms score.
Results  In patients with micro‐ and macroadenomas GH levels decreased to < 2·5 µg/l in 84·6% and 45%, serum IGF‐I levels normalized for age and gender in 61·5% and 35% of cases. Failure in achieving either GH < 2·5 µg/l or normal IGF‐I levels was found in none of the patients with micro‐ and in 45% of patients with macroadenoma. Median tumour volume was reduced by 54% (range: −90% to +350%) in micro‐ and by 49% (range −94% to −14%) in macroadenomas. Headache, perspiration and osteo‐arthralgias disappeared in 21%, paresthesias in 38%, fatigue in 26% and carpal tunnel syndrome in 15%. The treatment was well tolerated: more frequent adverse events were gastrointestinal (in 44%).
Conclusions  In both patients with micro‐ or macroadenoma, primary octreotide‐LAR treatment controls hormone excess, induces tumour shrinkage and improves symptoms of acromegaly with limited side effects and can be therefore successfully employed in patients with contraindications for surgery or in those who refuse surgery.