(EN) [PROBLEM] TO PROVIDE A COMPOUND USEFUL AS A CATHEPSIN S INHIBITOR. [MEANS FOR SOLUTION] THE PRESENT INVENTORS HAVE EXAMINED A COMPOUND THAT HAS A CATHEPSIN S INHIBITORY EFFECT AND IS USABLE AS AN ACTIVE INGREDIENT OF A PHARMACEUTICAL COMPOSITION FOR PREVENTING AND/OR TREATING AUTOIMMUNE DISEASE INCLUDING SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND LUPUS NEPHRITIS. ALLERGIES, OR GRAFT REJECTION OF AN ORGAN, BONE MARROW OR TISSUE, AND HAVE FOUND THAT A PHENYLDIFLUOROMETHYL-SUBSTITUTED PROLINAMIDE COMPOUND OF THE PRESENT INVENTION HAS THE CATHEPSIN S INHIBITORY EFFECT, THEREBY COMPLETING THE PRESENT INVENTION. THE PHENYLDIFLUOROMETHYL-SUBSTITUTED PROLINAMIDE COMPOUND OF THE PRESENT INVENTION HAS THE CATHEPSIN S INHIBITORY EFFECT AND IS USEFUL AS AN AGENT FOR PREVENTING AND/OR TREATING AUTOIMMUNE DISEASE INCLUDING SLE AND NEPHRITIS, ALLERGIES, OR GRAFT REJECTION OF AN ORGAN. BONE MARROW OR TISSUE. [SELECTED FIGURE] NIL
