Re: Re: Laboratory safety evaluation of bedinvetmab, a canine anti-nerve growth factor monoclonal antibody, in dogs

In their letter to the editor, Farrell et al., (2024) presented questions related to canine joint health after treatment with the anti-Nerve Growth Factor (NGF) monoclonal antibody (mAb) bedinvetmab, which was presented as a component of a non-clinical laboratory safety assessment published in Krautmann et al., (2021). Their questions appear to have stemmed from an anti-NGF mAb developed for the treatment of osteoarthritis in humans (tanezumab; FDA, 2021) which in 2021 failed to achieve marketing approval due to an unfavorable benefit: risk profile, primarily due to a syndrome called Rapidly Progressive Osteoarthritis (RPOA) which occurred more commonly in treatment groups when compared to controls. Farrell et. al. (2024) have posed questions on radiographic and histopathologic bone findings from studies included in Krautmann, et al., (2021) and communicated in the FDA’s Freedom of Information summary for Librela (FDA, 2023). These findings have previously been determined to be incidental and not bedinvetmab-associated. To address the questions posed, it is important to briefly define RPOA and summarize the syndrome in humans, review why the bone/joint findings in bedinvetmab safety studies in dogs are not indicative of RPOA or an RPOA-like condition, provide an update on joint health after use of bedinvetmab since market approval (>3 years in some markets), and summarize why Zoetis, the manufacturer of Librela, has confidence in joint safety after use of bedinvetmab in dogs.