Comment on: Butler et al. A Critical Analysis of the Clinical Use of Incretin-Based Therapies: Are the GLP-1 Therapies Safe? Diabetes Care 2013;36:2118–2125

In the July issue, Butler et al. (1) published a “point” narrative of a two-part Point-Counterpoint addressing the safety of glucagon-like peptide 1 (GLP-1) receptor agonists and dipeptidyl peptidase 4 (DPP-4) inhibitors. The review contains factual errors and some nontransparent or not fully elucidated statements relating to previously published studies.Nyborg et al. (2) reported the nonclinical pancreas toxicology data of liraglutide in ∼1,200 animals. Butler et al. refer to these data as treatment being stopped 2 weeks before the evaluation of tissues in nonhuman primates. This is incorrect. All the data reported in Nyborg et al. are from animals killed while on liraglutide treatment. Age was recorded for all animals, and treatment continued for 2 …