Combined treatment of somatostatin analogues with pegvisomant in acromegaly

Abstract

Treatment of acromegaly with monotherapy long-acting somatostatin analogues (LA-SSA) as primary treatment or after neurosurgery can only achieve complete normalization of insulin-like growth factor I (IGF-I) in roughly 40 % of patients. Recently, one of the acromegaly consensus groups has recommended switching to combined treatment of LA-SSA and pegvisomant (PEGV) in patients with partial response to LA-SSAs. This combination of LA-SSA and PEGV, a growth hormone receptor antagonist, can normalize IGF-I levels in virtually all patients, requiring that the adequate dose of PEGV is used. The required PEGV dose varies significantly between individual acromegaly patients. One of the advantages of the combination therapy is that tumor size control or even tumor shrinkage can be observed in a vast majority of patients. The main side effects of the combination treatment are gastrointestinal symptoms, lipohypertrophy and transient elevated liver transaminases. In this review we provide an overview of the efficacy and safety of the combined treatment of LA-SSAs with PEGV.

Keywords: Acromegaly; Growth hormone; Growth hormone receptor antagonist; Insulin-like growth factor I; Pegvisomant; Somatostatin analogues.

Fig. 1

Efficacy of combination treatment. Percentages of patients with IGF-I < 1.2 ×ULN and median PEGV doses (grey line, right Y-axis) are shown for every individual year during 9 years of combination treatment, LA-SSA combined with PEGV. Median PEGV dose is in mg weekly. Cumulative numbers of the included patients at each treatment year are depicted at the bottom of every bar. All patients (n = 112) were treated for at least 1 year, 17 patients were treated for a maximum of 9 years of follow up. LA-SSA: Long-acting somatostatin analogues; PEGV pegvisomant, IGF-I insulin like growth factor I. This figure was reproduced with permission from [12]