“…Some studies included treatments approved in limited markets such as beraprost [ 38 , 40 , 48 , 50 , 51 , 57 , 61 , 65 , 67 ]. In nine studies, drugs targeting one pathway only were investigated: prostacyclins in five studies [ 40 , 47 , 59 , 61 , 64 ] and ERAs in four studies [ 25 , 45 , 58 , 62 ]. Fifteen studies [ 17 , 20 , 21 , 24 , 25 , 32 , 34 , 35 , 39 , 45 , 58 , 60 , 62 , 63 , 65 ] focused on oral treatments only.…”