Subsequently , six non-smoking men with mild allergic asthma received single doses of RPL554 ( three received 0009 mg/kg and three received 0018 mg/kg ) in an open-label , adaptive study , and then ten men with mild allergic asthma were randomly assigned to receive placebo or RPL554 ( 0018 mg/kg ) by a computer-generated randomisation table for an assessment of safety , bronchodilation , and bronchoprotection .