Endocrine Abstracts

Introduction: Acromegaly is chronic debilitating disease related with excess GH and insülin-like growth factor 1 (IGF1) secretion. Pegvisomant is a GH receptor antagonist that competes with endogenous GH for its receptor and is often used as a medical therapy in patients with inadequate response to somatostatin analogs.

Methods: Forty-six patients are followed with the diagnosis of acromegaly in our clinic. We present the results of six acromegalic patients (five female and one male patient) treated with pegvisomant.

Results: The mean age was 49.8 years and the mean disease duration was 12.5 years. All of them were treated with surgery. Five patients received external radiotherapy and/or gamma knife surgery. All of the patients received octreotide LAR 30 mg/month therapy. Despite these therapies, IGF1 levels were higher than the upper limit of sex and age matched levels. We evaluate the patients for relapse or residual lesions before pegvisomant treatment and found macroadenoma in two patient, micraoadenoma in one patient and no lesion in three patients. Mean IGF1 level was 558 ng/ml before pegvisomant therapy. After 40 mg loading dose, we started pegvisomant 10 mg/day. Mean therapy duration was 11.6 months. During follow-up, IGF1 levels decreased in four patients, however, remained high in two patients. Therefore, the dose is increased to 15 mg/day in these two patients. IGF1 levels decreased in one of them, but was still high in the other. In one patient with macroadenoma, pegvisomant was stopped at the second month due to lipodistrophy. No adverse effects were seen in other patients. Treatment is completed to one year only in two patients and we found no increase in adenoma sizes in these patients.

Conclusion: Four of six patients responded to pegvisomant treatment. Pegvisomant seems to be effective in patients in whom remission cannot be acheived with other modes of therapy.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.