Pharmacological characterization of GLPG1972/S201086, a potent and selective small-molecule inhibitor of ADAMTS5

OBJECTIVE

A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) is a key enzyme in degradation of cartilage in osteoarthritis (OA). We report the pharmacological characterization of GLPG1972/S201086, a new, potent and selective small-molecule ADAMTS5 inhibitor.

METHODS

Potency and selectivity of GLPG1972/S201086 for ADAMTS5 were determined using fluorescently labeled peptide substrates. Inhibitory effects of GLPG1972/S201086 on interleukin-1α-stimulated glycosaminoglycan release in mouse femoral head cartilage explants and on interleukin-1β-stimulated release of an ADAMTS5-derived aggrecan neoepitope (quantified with ELISA) in human articular cartilage explants were determined. In the destabilization of the medial meniscus (DMM) mouse and menisectomized (MNX) rat models, effects of oral GLPG1972/S201086 on relevant OA histological and histomorphometric parameters were evaluated.

RESULTS

GLPG1972/S201086 inhibited human and rat ADAMTS5 (IC50 ± SD: 19 ± 2 nM and <23 ± 1 nM, respectively), with 8-fold selectivity over ADAMTS4, and 60->5,000-fold selectivity over other related proteases in humans. GLPG1972/S201086 dose-dependently inhibited cytokine-stimulated aggrenolysis in mouse and human cartilage explants (100% at 20 μM and 10 μM, respectively). In DMM mice, GLPG1972/S201086 (30-120 mg/kg b.i.d) vs vehicle reduced femorotibial cartilage proteoglycan loss (23-37%), cartilage structural damage (23-39%) and subchondral bone sclerosis (21-36%). In MNX rats, GLPG1972/S201086 (10-50 mg/kg b.i.d) vs vehicle reduced cartilage damage (OARSI score reduction, 6-23%), and decreased proteoglycan loss (∼27%) and subchondral bone sclerosis (77-110%).

CONCLUSIONS

GLPG1972/S201086 is a potent, selective and orally available ADAMTS5 inhibitor, demonstrating significant protective efficacy on both cartilage and subchondral bone in two relevant in vivo preclinical OA models.

alpha-t-butyl- and alpha-i-propyl-ortho-hydroxybenzylamines: racemic synthesis/resolution and asymmetric synthesis

Efficient routes to alpha-tert-butyl- and alpha-iso-propyl-ortho-hydroxybenzylamines 1a and 1b are described. Highly enantioenriched 1a and 1b were obtained by resolution of the methoxy derivatives 2 by recrystallization of the salts formed with mandelic acid followed by Lewis acid mediated demethylation. The chiral 1,3-amino alcohol 1a has also been obtained in an asymmetric synthesis with the key step a diastereoselective alkylation of the imine obtained by condensation of o-anisaldehyde with phenyl glycinol. The absolute stereochemistry of these 1,3-aminophenols was determined by CD spectroscopy of the salicylideneamines 12 and by an X-ray structure analysis of the salt formed between (R)-mandelic acid and (S)-alpha-tert-butyl-ortho-methoxybenzylamine ((S)-2a).