A new class of potent matrix metalloproteinase 13 inhibitors for potential treatment of osteoarthritis: Evidence of histologic and clinical efficacy without musculoskeletal toxicity in rat models
Authors: Baragi Vijaykumar M. , Becher Gabriel , Bendele Alison M. , Biesinger Ralf , Bluhm Harald , Boer Jürgen , Deng Hongbo , Dodd Rory , Essers Michael , Feuerstein Tim , Gallagher Brian M. , Gege Christian , Hochgürtel Matthias , Hofmann Michael , Jaworski Andreas , Jin Lixia , Kiely Andrew , Korniski Brian , Kroth Heiko , Nix Darrell , Nolte Bert , Piecha Dorothea , Powers Timothy S. , Richter Frank , Schneider Matthias , Steeneck Christoph , Sucholeiki Irving , Taveras Arthur , Timmermann Andreas , Van Veldhuizen Joshua , Weik Juergen , Wu Xinyuan , Xia Bing 
Published: June 2009

AbstractObjectiveMatrix metalloproteinases (MMPs) have long been considered excellent targets for osteoarthritis (OA) treatment. However, clinical utility of broad‐spectrum MMP inhibitors developed for this purpose has been restricted by dose‐limiting musculoskeletal side effects observed in humans. This study was undertaken to identify a new class of potent and selective MMP‐13 inhibitors that would provide histologic and clinical efficacy without musculoskeletal toxicity.MethodsSelectivity assays were developed using catalytic domains of human MMPs. Freshly isolated bovine articular cartilage or human OA cartilage was used in in vitro cartilage degradation assays. The rat model of monoiodoacetate (MIA)–induced OA was implemented for assessing the effects of MMP‐13 inhibitors on cartilage degradation and joint pain. The surgical medial meniscus tear model in rats was used to evaluate the chondroprotective ability of MMP‐13 inhibitors in a chronic disease model of OA. The rat model of musculoskeletal side effects (MSS) was used to assess whether selective MMP‐13 inhibitors have the joint toxicity associated with broad‐spectrum MMP inhibitors.ResultsA number of non–hydroxamic acid–containing compounds that showed a high degree of potency for MMP‐13 and selectivity against other MMPs were designed and synthesized. Steady‐state kinetics experiments and Lineweaver‐Burk plot analysis of rate versus substrate concentration with one such compound, ALS 1‐0635, indicated linear, noncompetitive inhibition, and Dixon plot analysis from competition studies with a zinc chelator (acetoxyhydroxamic acid) and ALS 1‐0635 demonstrated nonexclusive binding. ALS 1‐0635 inhibited bovine articular cartilage degradation in a dose‐dependent manner (48.7% and 87.1% at 500 nM and 5,000 nM, respectively) and was effective in inhibiting interleukin‐1α– and oncostatin M–induced C1,C2 release in human OA cartilage cultures. ALS 1‐0635 modulated cartilage damage in the rat MIA model (mean ± SEM damage score 1.3 ± 0.3, versus 2.2 ± 0.4 in vehicle‐treated animals). Most significantly, when treated twice daily with oral ALS 1‐0635, rats with surgically induced medial meniscus tear exhibited histologic evidence of chondroprotection and reduced cartilage degeneration, without observable musculoskeletal toxicity.ConclusionThe compounds investigated in this study represent a novel class of MMP‐13 inhibitors. They are mechanistically distinct from previously reported broad‐spectrum MMP inhibitors and do not exhibit the problems previously associated with these inhibitors, including selectivity, poor pharmacokinetics, and MSS liability. MMP‐13 inhibitors exert chondroprotective effects and can potentially modulate joint pain, and are, therefore, uniquely suited as potential disease‐modifying osteoarthritis drugs.