FP27-5 Long-term efficacy of long-acting somatostatin analogues in combination with pegvisomant in 111 acromegalic patients, a single-centre study with up to 8 years of follow-up

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: FP27-Pituitary: Acromegaly and Prolactinoma
Clinical
Sunday, June 16, 2013: 10:45 AM-11:15 AM
Presentation Start Time: 11:05 AM
Room 135 (Moscone Center)

Poster Board SUN-93
Sanne Franck*1, Aart Jan van der Lely2 and Sebastian JCMM Neggers2
1erasmus university medical center rotterdam, Rotterdan, Netherlands, 2Erasmus MC, Rotterdam, Netherlands
Introduction

Pegvisomant (PEGV) has an efficacy of >90% to control insulin-like growth factor (IGF1), however in everyday practice a limited efficacy of 63% was reported. Aim; to assess efficacy in the largest single center cohort of acromegalics using PEGV.

Methods

111 subjects (65 male) were not controlled with high-dose somatostatin analogues (LA-SRIF) for at least 6 months. To control acromegaly, all subjects added PEGV. IGF1 and Growth hormone (GH) levels (start, lowest and last values) were retrospectively re-assessed in a single run. IGF1 was measured by the Immulite2000 and GH by the IDS-iSYS immuno-assay, to assess GH without interference of PEGV. Results are expressed as median (interquartile range). At baseline 80% of the subjects (age; 47.3 years (38.4-59.0)) had a macro-adenoma.

Results

Duration of PEGV treatment was 4.0 years (1.9-6.2). Normalization of IGF-1 was observed in 96%, with an IGF-1 of 17.9nmol/L (13.0-23.8) and a IGF-1 of 0.6 (0.4-0.7) upper limit of normal (ULN). In all uncontrolled subjects, IGF-1 ratios were ≤1.2 ULN.  At the last visit, weekly PEGV dose of 80mg (60-120mg) was used during combination treatment with LA-SRIFs. No significant differences in PEGV dose, needed to control IGF1 were observed between sexes, diabetic/non-diabetic patients, surgery/non-surgery and Gilbert’s polymorphism/non-Gilberts polymorphism. Baseline IGF-1 levels were associated with the required dosage of PEGV to normalize IGF-1 levels (R=0.33 P=0.00).

Baseline GH levels (on LA-SRIFs) were not significantly different compared with GH during PEGV and LA-SRIFs treatment (p=0.57). Two subgroups were defined according to surgical status (surgery vs. non-surgery). After surgery GH seem to decrease during treatment (8.7 and 4.5nmol/L), while primary medical treatment GH seem to increase (4.0 and 4.5nmol/L), although not significantly different (p=0.091(post-radiotherapy-group was excluded)).

Conclusion

Up to eight years, combination of LA-SRIF and PEGV in acromegaly has an efficacy of 96%. GH levels do not change during treatment.

Nothing to Disclose: SF, AJV, SJN

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm