Discovery and development of 5-[(5S,9R)-9-(4-cyanophenyl)-3-(3,5-dichlorophenyl)-1-methyl-2,4-dioxo-1,3,7-triazaspiro[4.4]non-7-yl-methyl]-3-thiophenecarboxylic acid (BMS-587101)--a small molecule antagonist of leukocyte function associated antigen-1.

LFA-1 (leukocyte function-associated antigen-1), is a member of the β2-integrin family and is expressed on all leukocytes. This letter describes the discovery and preliminary SAR of spirocyclic hydantoin based LFA-1 antagonists that culminated in the identification of analog 8 as a clinical candidate. We also report the first example of the efficacy of a small molecule LFA-1 antagonist in combination with CTLA-4Ig in an animal model of transplant rejection.