Effects of Pegvisomant and Pasireotide LAR on vertebral fractures in acromegaly resistant to First-Generation SRLs.

PURPOSE: Osteopathy is an emerging complication of acromegaly. In somatostatin receptor ligands (SRL)-resistant patients, Pegvisomant (PegV) and Pasireotide LAR (Pasi) are used for acromegaly treatment, but their effect on skeletal health is still not defined.
METHODS: In a longitudinal retrospective international study, we evaluated incidence of radiological vertebral fractures (VFs) in 55 pts with acromegaly resistant to first-generation SRL.
RESULTS: At study entry, prevalent VFs occurred in 23 patients (41.8%). Biochemical acromegaly control was reached in 66.7% of patients on PegV and in 66.7% of patients on Pasi. During the follow-up, incident VFs (iVFs) were detected in 16 patients (29.1%). Occurrence of iVFs was associated with prevalent VFs (p=0.002), persistence of active acromegaly (p=0.01) and higher value of IGF-I during follow-up (p=0.03). Among patients with active disease at last visit, iVFs occurred less frequently in patients on treatment with Pasi (25%) compared to PegV (77.8% p=0.04), independently of the IGF-I values (p=0.9). In patients who reached biochemical control, 22.7% on Peg-V and 12.5% on Pasi had iVFs (p=0.4). Among both treatment groups, the presence of pre-existent VFs was the main determinant for iVFs.
CONCLUSION: Our data show for the first time that patients with biochemically active disease treated with Pasi had lower risk of iVFs vs those treated with PegV . It also confirms that the presence of pre-existent VFs was the main determinant for iVFs. Additional studies on larger populations and with longer follow-up are needed to confirm our data and disclose the mechanisms underlying our findings. © Endocrine Society 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.