Abstract: Use of a compound which is a biphenyl derivative of formula (I), or a pharmaceutically acceptable salt thereof, for the treatment of Hepatitis C wherein the variables are described herein.

Abstract: A compound which is a biphenyl derivative of formula (I), or a pharmaceutically acceptable salt thereof wherein: R1 is a C1-C6 alkyl group or a moiety -A1, -L1-A1, -A1-A1?, -L1-A1-A1?, -A1-L1-A1?, -A1-Y1-A1?, -A1-Het1-A1?, -L1-A1-Y1-A1?, -L1-A1-Het1-A1?, -L1-Het1-A1, -L1-Y1-A1, -L1-Y1-Het1-A1, -L1-Het1-Y1-A1, -L1-Y1-Het1-L1?, -A1-Y1-Het1-A1?, -A1-Het1-Y1-A1?, -A1-Het1-L1-A1?, -A1-L1-Het1-A1? or -L1-Het1-L1?; -A and B are the same or different and each represent a direct bond or a —CO—NR?—, —NR?—CO—, —NR?—CO2—, —CO—, —NR?—CO—NR?—, —NR?—S(O)2—, —S(O)2—NR?—, —SO2—, —NR?—, —NR?—CO—CO—, —CO—O—, —O—CO—, —(C1-C2 alkylene)-NR?— or —(C1-C2 hydroxyalkylene)-NR?-moiety, wherein R? and R? are the same or different and each represent hydrogen or C1-C4 alkyl; —R2 and R3 are the same or different and each represent C1-C4 alkyl, C1-C4 alkoxy, C1-C4 haloalkyl, C1-C4 haloalkoxy or halogen; n and m are the same or different and each represent 0 or 1; R4 is a C1-C6 alkyl group or a moiety -A4, -L4-A4, -A4-A4?, -L4-A4-A4?, -A4-L4