RPL554 produced rapid bronchodilation in patients with asthma with an FEV1 increase at 1 h of 520 mL ( 95 % CI 320-720 ; p < 00001 ) , which was a 14 % increase from placebo , and increased the PC20MCh by 15 doubling doses ( 95 % CI 063-228 ; p = 0004 ) compared with placebo .