The primary aims were to evaluate the superiority of brodalumab over placebo at week 12 with respect to at least a 75 % reduction in the psoriasis area-and-severity index score ( PASI 75 ) and a static physician 's global assessment ( sPGA ) score of 0 or 1 ( clear or almost clear skin ) , as well as the superiority of brodalumab over ustekinumab at week 12 with respect to a 100 % reduction in PASI score ( PASI 100 ) .