ABSTRACT Monoclonal antibodies (mAbs) targeting nerve growth factor (NGF) represent a novel therapeutic approach for managing acute and chronic pain in humans and animals. However, their potential misuse as pain‐masking agents in competitive equine sports raises significant welfare and integrity concerns. To enhance understanding of the elimination profile of anti‐NGF mAb if misused in horses, this study describes the first administration of bedinvetmab (a canine anti‐NGF mAb) in three geldings, establishing its plasma elimination profile following subcutaneous administration. Bedinvetmab plasma concentrations were determined using a recently developed generic method involving affinity purification with Protein A magnetic beads, followed by tryptic digestion and identification of a proteotypic peptide via capillary flow high performance liquid chromatography coupled with high resolution tandem mass spectrometry (HPLC‐HRMS). Significant interindividual variability was observed. Maximum plasma concentrations ranged from approximately 0.97 to 6.0 μg/mL and occurred 1–2 days post‐administration. Bedinvetmab was detectable up to the last sampled time point (34 days) in two horses (estimated concentrations: 1.9 and 1.7 μg/mL), while in the third horse, it was detectable only up to 5 days post‐administration (0.13 μg/mL). Although the mechanisms underlying this variability were unclear, these results demonstrate that mAbs developed for other species can exert prolonged effects in horses, underscoring the importance of implementing effective doping controls for the misuse of therapeutic mAbs.
Cheung et al. (2026) studied this question.