Efficacy and tolerability of treatment with pegvisomant in acromegaly: an overview of literature

Abstract

Introduction: Acromegaly is characterized by increased release of growth hormone (GH) and IGF-I generally induced by a pituitary adenoma. Therapies for acromegaly aim at controlling tumor growth and normalizing hormonal excess, and include surgery, pharmacotherapy, and radiotherapy.

Area covered: This review focuses on efficacy and tolerability of the GH receptor antagonist pegvisomant (PEG), widely used in acromegaly as second- or third-line treatment, mainly after unsuccessful surgery and/or radiotherapy, or in patients with a proven resistance to conventional somatostatin analogs (SSA). The response to PEG takes into account control of IGF-I excess and improvement of clinical symptoms directly related to IGF-I hypersecretion, whereas PEG does not exert a direct action on GH oversecretion and tumor mass. The response to PEG treatment depends on proper dose adjustment and patient compliance, as it is approved as daily subcutaneous injection. However, PEG can be added to SSA in patients non- or partly responders to SSA, or converted from daily to weekly administration with similar effectiveness of daily monotherapy.

Expert opinion: PEG is safe and well tolerated, and main safety focuses are on the potential risk of increased GH and pituitary tumor size, liver enzyme elevation, and injection site reactions.

Keywords:

• acromegaly
• combined treatment
• disease control
• IGF-I normalization
• liver enzymes
• monotherapy
• pegvisomant
• pituitary tumor
• side effects
• tumor volume

Declaration of interest

A Colao has been principal investigator of research studies from Novartis, Ipsen, Pfizer, and Lilly, has received research grants from Ferring, Lilly, Ipsen, Merck-Serono, Novartis, Novo-Nordisk, and Pfizer, has been occasional consultant for Novartis, Ipsen, and Pfizer, and has received fees and honoraria from Ipsen, Novartis, and Pfizer. R Pivonello has been principal investigator of research studies from Novartis, has received research grants from Novartis, Pfizer, Viropharma, and IBSA, has been occasional consultant for Novartis, Ipsen, Pfizer, Viropharma, Ferring, Italfarmaco, and received fees and honoraria for presentations from Novartis. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.