Suppression of cathepsin K biomarker in synovial fluid as a free-drug–driven process

Autor: Bennett Ma, Gregg Wesolowski, Bin Luo, Traci Lifsted, Keith Wessner, Gary Adamson, Helmut Glantschnig, Laura S Lubbers
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Journal of Circulating Biomarkers, Vol 8 (2019)
Druh dokumentu: article
ISSN: 1849-4544
18494544
DOI: 10.1177/1849454418821819
Popis: Cathepsin K (CatK) inhibitors exhibited chondroprotective and pain-reducing effects in animal models, however, improvements were relatively modest at dose levels achieving maximal suppression of CatK biomarkers in urine. In this report, a previously characterized CatK inhibitor (MK-1256) is utilized to explore the potential of reduced target engagement and/or suboptimal exposure (free drug) as limiting factors to the pharmacological potential of CatK inhibitors in the knee joint. Following oral administration of MK-1256 at a dose level achieving maximal inhibition of urinary biomarker (helical peptide) in dogs, full suppression of the biomarker in synovial fluid was observed. Subsequent tissue distribution studies conducted in dogs and rabbits revealed that MK-1256 levels in synovial fluid and cartilage were consistent with the free-drug hypothesis. Reasonable projection (within twofold) of drug levels in these tissues can be made based on plasma drug concentration with adjustments for binding factors. These results indicate that the previously observed efficacies in the animal models were not limited by compound distribution or target engagement in the knee tissues.
Databáze: Directory of Open Access Journals