Endocrine Abstracts (2011) 26 P216

Long-term treatment of acromegaly with pegvisomant (Somavert): cross-sectional observations from ACROSTUDY, a post-marketing, international, safety, surveillance study

A J van der Lely1, F Lundgren2, B M K Biller3, T Brue4, J Cara5, E Ghigo6, J Hey Hadavi5, N Rajicic5, Bernhard Saller7, John Sanocki8, Christian Strasburger9, Susan Webb10 & Maria Koltowska Haggstrom2

1Erasmus University Medical Centre, Rotterdam, The Netherlands; 2ACROSTUDY Pfizer Endocrine Care, Sollentuna, Sweden; 3Massachusetts General Hospital, Boston, Massachusetts, USA; 4Université de la Méditerranée, Marseille, France; 5Pfizer Inc., New York, USA; 6Università di Torino, Turin, Italy; 7Pfizer Ltd, Tadworth, UK; 8Pfizer Inc., New London, Connecticut, USA; 9Charité-Universitätsmedizin, Berlin, Germany; 10Hospital S Pau, CIBERER 747, Universitat Autònoma de Barcelona, Barcelona, Spain.

Introduction: Somavert is a GH receptor blocker, which inhibits hepatic production of IGF1. While it has been approved for the treatment of acromegaly since 2003 there are few data regarding its effects in everyday clinical practice.

Methods/design: ACROSTUDY is an open-label, international, prospective, non-interventional, post-marketing surveillance study monitoring the long-term safety and efficacy of Somavert.

Results: As of December 31, 2009 data from 1288 patients (51% men) were available. The majority of patients came from Germany (31%), France (15%), Spain and Italy (both 14%). Mean (S.D.) age (years) of patients at diagnosis of acromegaly was 42 (13.5) and at Somavert start, 50 (14.0). Mean (S.D.) duration of Somavert treatment was 3.7 (1.9) years. Before Somavert start, other treatments were reported as follows: medical therapy and surgery in 43.5% of patients; medical therapy, radiation and surgery in 24.4%; medical therapy only in 18.3%; surgery only in 4.2%; radiation and surgery in 2%; medical therapy and radiation in 1.6% and only radiation in 0.1%. In 5.9% of patients no previous treatment was reported. At Somavert start (n=839) 86% of patients were reported as having increased IGF1 concentrations. After 1 year of treatment (n=769), at a mean dose 14.8 mg/day, in 57%, normal IGF1 concentrations were reported. Subsequent IGF1 normalization rates were reported as follows: 2 years (n=705), mean dose 15.6 mg/day – 60%; 3 years (n=563), mean dose 15.9 mg/day – 60%; 4 years (n=406), mean dose 16.8 mg/day – 63%; 5 years (n=253), mean dose 17.5 mg/day – 63%.

Conclusions: The majority of patients experienced normalization of IGF1 on relatively low doses of Somavert. The normalization rate was lower than in clinical trials. This might be explained by insufficient upward dose titration, less rigorous, frequent monitoring and lower patient compliance than in clinical trials, longer follow-up, and unselected patients with severe acromegaly, resistant to other medical treatments.