Abstract: This invention pertains generally to the field of therapeutic compounds, and more particularly, to certain bicyclosulfonyl acid (BCSA) compounds which act as inhibitors of Tumour Necrosis Factor-? Converting Enzyme (TACE). The compounds are useful in the treatment of conditions mediated by TNF-?, such as rheumatoid arthritis; inflammation; psoriasis; septic shock; graft rejection; cachexia; anorexia; congestive heart failure; post ischaemic reperfusion injury; inflammatory disease of the central nervous system; inflammatory bowel disease; insulin resistance; HIV infection; cancer; chronic obstructive pulmonary disease (COPD); and asthma. The present invention also pertains to pharmaceutical compositions comprising such compounds, and the use of such compounds and compositions, both in vitro and in vivo, in the inhibition of TACE, and in the treatment of conditions that are ameliorated by the inhibition of TACE.