CONTEXT: There is concern that pegvisomant could be associated with a higher risk of tumor growth. The rate and possible determinants of this tumor growth are unknown. OBJECTIVE: The objective of the study was to investigate the clinical, immunohistological, and molecular factors conditioning tumor growth in patients taking pegvisomant. DESIGN AND SETTING: This was a cross-sectional study performed from 2004 to 2010 in four university hospitals in Spain. PATIENTS: Seventy-five acromegalic patients with active disease resistant to somatostatin analogs treated with pegvisomant were followed up for a mean of 29 ± 20 months. MAIN OUTCOME MEASURES: Magnetic resonance images before initiation of pegvisomant, at 6 months, and then yearly were examined in all patients. Immunohistological and molecular studies were performed in tumors that grew. RESULTS: A significant increase in tumor size was observed in five patients (6.7%). Absence of previous irradiation (P = 0.014) and shorter duration of prepegvisomant somatostatin analog therapy (P < 0.001) were associated with an increased risk of tumor growth. A stepwise multivariate linear regression analysis (R(2) = 0.334, P < 0.001) identified the duration of somatostatin analog therapy prior to pegvisomant (beta = -4.509, P = 0.014) as the only significant predictor of tumor growth. In those tumors that grew, GH expression and insulin receptor expression were higher (P = 0.033 in both cases) than in the control group. CONCLUSIONS: No previous radiotherapy, shorter duration of prepegvisomant somatostatin analog therapy, and higher tumor expression of GH and insulin receptor could be risk factors for tumor growth during pegvisomant therapy.
CONTEXT: There is concern that pegvisomant could be associated with a higher risk of tumor growth. The rate and possible determinants of this tumor growth are unknown. OBJECTIVE: The objective of the study was to investigate the clinical, immunohistological, and molecular factors conditioning tumor growth in patients taking pegvisomant. DESIGN AND SETTING: This was a cross-sectional study performed from 2004 to 2010 in four university hospitals in Spain. PATIENTS: Seventy-five acromegalicpatients with active disease resistant to somatostatin analogs treated with pegvisomant were followed up for a mean of 29 ± 20 months. MAIN OUTCOME MEASURES: Magnetic resonance images before initiation of pegvisomant, at 6 months, and then yearly were examined in all patients. Immunohistological and molecular studies were performed in tumors that grew. RESULTS: A significant increase in tumor size was observed in five patients (6.7%). Absence of previous irradiation (P = 0.014) and shorter duration of prepegvisomant somatostatin analog therapy (P < 0.001) were associated with an increased risk of tumor growth. A stepwise multivariate linear regression analysis (R(2) = 0.334, P < 0.001) identified the duration of somatostatin analog therapy prior to pegvisomant (beta = -4.509, P = 0.014) as the only significant predictor of tumor growth. In those tumors that grew, GH expression and insulin receptor expression were higher (P = 0.033 in both cases) than in the control group. CONCLUSIONS: No previous radiotherapy, shorter duration of prepegvisomant somatostatin analog therapy, and higher tumor expression of GH and insulin receptor could be risk factors for tumor growth during pegvisomant therapy.
Authors: Andrea Giustina; Philippe Chanson; David Kleinberg; Marcello D Bronstein; David R Clemmons; Anne Klibanski; Aart J van der Lely; Christian J Strasburger; Steven W Lamberts; Ken K Y Ho; Felipe F Casanueva; Shlomo Melmed Journal: Nat Rev Endocrinol Date: 2014-02-25 Impact factor: 43.330
Authors: I Bernabeu; C Alvarez-Escolá; A E Paniagua; T Lucas; I Pavón; J M Cabezas-Agrícola; F F Casanueva; M Marazuela Journal: Pituitary Date: 2013-03 Impact factor: 4.107
Authors: Pamela U Freda; Murray B Gordon; Nicky Kelepouris; Peter Jonsson; Maria Koltowska-Haggstrom; A J van der Lely Journal: Endocr Pract Date: 2015-03 Impact factor: 3.443
Authors: I Bernabeu; A Pico; E Venegas; J Aller; C Alvarez-Escolá; J A García-Arnés; M Marazuela; P Jonsson; N Mir; M García Vargas Journal: Pituitary Date: 2016-04 Impact factor: 4.107