Chapter 14 - Medical treatment in acromegaly

Abstract

Acromegaly is an insidious chronic disorder, characterized by GH excess and IGF-I hyperproduction, usually caused by a pituitary adenoma. It is associated with a high cardiovascular risk due to several metabolic complications, such as hyperglycemia, diabetes, dyslipidemia, arterial hypertension, and obstructive sleep apnea, and increased risk to develop cancer has been widely reported. Since the diagnostic delay still represents a burden in the modern clinical management, patients frequently harbor macroadenomas, which are associated with low chance to be removed by neurosurgical procedures. Therefore medical therapy is recommended in those patients not cured by surgery or in those where surgery is contraindicated or refused. In particular, first-generation somatostatin receptor ligands (SRLs), octreotide LAR and lanreotide ATG, were shown to be effective in almost 50% of patients providing biochemical control and significant tumor shrinkage. Indeed, still a relevant number of acromegaly subjects maintain active disease during first-line medical therapies and second-line drugs should be prescribed according to additional concerns, like tumoral mass or glycometabolic impairment. Pasireotide LAR showed a higher efficacy in reducing GH and IGF-I levels as compared with first-generation SRLs, with associated additive tumor shrinkage in some patients. However, drug-induced hyperglycemia and diabetes still represent an important side effect during pasireotide treatment. Pegvisomant, as GH antagonist, may represent a valid option in those patients resistant to SRLs whit a positive effect also on glucose metabolism.