Fused pyrazole urea analogs as glucosylceramide synthase inhibitors

A compound of the formula I:

• or a pharmaceutically acceptable salt thereof, wherein
• a) X, Y, Z and W are each absent and each R2 independently is selected from C1-C4 alkyl, C1-C4 fluoroalkyl, hydroxy, —C1-C4alkoxy, and halogen;
• or
• b) X is CH2 or O, Y is CH2 or O, Z is CH2 or O, and W is CH2 or O provided that no more than one of X, Y, Z or W is O, and R2 is absent;
• R1 is aryl(C0-C4 alkyl), heteroaryl(C0-C4 alkyl), cycloalkyl(C0-C4 alkyl), heterocycloalkyl(C0-C4 alkyl), aryloxy, heteroaryloxy, cycloalkyloxy, heterocycloalkyloxy, wherein RI is substituted by 0, 1, 2, or 3 R4;
• each R4 independently is selected from halogen, C1-C4alkyl, C1-C4 alkoxy, C1-C4 fluoroalkyl, C1-C4 fluoroalkyloxy, oxo, and hydroxy;
• and
• each R3 independently is selected from halogen, C1-C4alkyl, C1-C4 alkoxy, C1-C4 fluoroalkyl, C1-C4 fluoroalkyloxy, oxo, —(C1-C4 alkyl)OH, and hydroxy.