The short-term effects of CGRP monoclonal antibodies on bone turnover: A prospective cohort study

Abstract

Calcitonin gene-related peptide monoclonal antibodies (CGRP mAb) are an effective treatment of migraine however may have possible off-target effects. Pre-clinical studies implicate CGRP in several aspects of bone turnover and homeostasis. The clinical effect of CGRP mAb on bone turnover is not known, however. Between June 2021 and July 2022, a multi-centre prospective cohort study was undertaken with eligible patients undergoing paired testing of the validated bone turnover markers procollagen type I N-terminal propeptide (P1NP) and serum C-terminal telopeptide of type I collagen (CTX) prior to and at least three months following administration of a CGRP mAb. A total of 45 patients with a mean age of 41.8 (SD 11.9) were included in the final analysis, all of whom received a ligand-targeting CGRP mAb. Administration of a CGRP mAb was associated with a statistically significant increase in P1NP from 44.5 microg/L to 51.5 microg/L (p = 0.004), but no significant change in CTX. In otherwise homeostatic conditions, short-term administration of a CGRP mAb is associated with increased P1NP, a bone formation marker but not with increased CTX, a bone resorption marker. Further study is required to validate these findings over longer time periods, in a larger cohort, and in pre-existing states of increased calcium stress and bone-turnover.