The present application describes novel cyclic sulfone derivatives of formula I: ##STR1##

or pharmaceutically acceptable salt or prodrug forms thereof, which are useful as inhibitors of matrix metalloproteinases (MMP), TNF- converting enzyme (TACE), aggrecanase, or a combination thereof. In formula I, A is selected from —COR⁵, —CO₂H, —CO₂R⁶, —C(O)NHOH, —C(O)NHOR⁵, —C(O)NHOR⁶, —NHR^a, —N(OH)COR⁵, —N(OH)CHO, —SH, —CH₂SH, —S(O)(NH)R^a, —S(NH)₂R^a, —SC(O)R^a, —PO(OH)₂, and —PO(OH)NHR^a; B is a thiomorpholine ring; X is absent or is CR³R⁴; and U^a, X^a, Y^a, Z^a, R¹, R², R^b, and q are defined in the present specification.