Enflicoxib for the long-term management of canine osteoarthritis. External validation of a A population pharmacokinetic model in external validation conducted in dogs with osteoarthritis

Josep Homedes^1*Josep-Maria Cendrós²Marta Salichs¹Gregorio Encina³Jose Miguel Vela³

• ¹Animalcare Group plc, York, United Kingdom
• ²Universitat de Barcelona, Barcelona, Spain
• ³WeLab Barcelona, Barcelona, Spain

Enflicoxib is a Cox-2 selective NSAID indicated for the treatment of pain and inflammation in canine osteoarthritis (OA). Canine OA is a chronic progressive disease that requires long-term therapy. The suitability of enflicoxib for its long term use was assessed by analysing the concentrations determined in plasma samples from dogs included in a field clinical study using a previously established population pharmacokinetic (popPK) model. One hundred and nine client owned dogs with OA of different breeds, age and weight were enrolled and treated with enflicoxib weekly for 6 months at the recommended dose. Safety was assessed clinically and by repeated blood and urine analysis. Two plasma samples were obtained from 83 dogs that received at least one enflicoxib dose.pyrazol metabolite were determined, modelled, and compared with the predictions of the previously established popPK model in healthy Beagle dogs. Enflicoxib and pyrazol metabolite plasma levels could be adequately predicted by the established popPK model. No covariates other than body weight had any influence in the PK parameters. No overaccumulation of either compound was observed. The established popPK model in healthy Beagle dogs can predict the PK behaviour of enflicoxib and its pyrazol metabolite in dogs of any breed with OA. The lack of time-dependent PK provides a PK rationale to support continuous enflicoxib treatment for as long as therapeutically required.