(2R)-2-[([1,1μ-Biphenyl]-4-ylsulfonyl)(1-methylethoxy)amino]-N-hydroxy-3-methyl-butanamide, (R)-N-Hydroxy-2-(N-isopropoxybiphenyl-4-ylsulfonamido)-3-methylbutanamide

ARP 101 is a selective inhibitor of the MMP-2 (metalloproteinase-2 ) and, to lesser extent, MMP-9 (metalloproteinase-9), both of which have been shown to play a role in certain key functions of tumour cells, facilitating metastatic tumour dispersion and angiogenesis, resistance to apoptosis and actication of EGF receptors. Studies of ARP 101 show in vitro inhibition of HT1080 sarcoma cell growth on matrigel. ARP 101 has shown ~250 fold selectivity of MMP-2 over MMP-1 and ~100 fold of MMP-9 over MMP-1.