Of 219 patients who entered the maintenance period , PASI75 was achieved by week 28 in 35 ( 714 % ) of 49 who continued on 20 mg ponesimod and 41 ( 774 % ) of 53 on 40 mg ponesimod , and in 19 ( 422 % ) of 45 who swapped from 20 mg to placebo and 19 ( 404 % ) of 47 from 40 mg to placebo .