Patients ( N = 139 ; age , 18 y ) with moderate-to-severe active Crohn 's disease were assigned randomly to groups given 1 mg ( n = 36 ) , 5 mg ( n = 34 ) , or 15 mg ( n = 35 ) tofacitinib or placebo ( n = 34 ) , twice daily for 4 weeks , at 48 centers in 12 countries .