Despite receiving a reduced glucocorticoid dose , patients in the mepolizumab group , as compared with those in the placebo group , had a relative reduction of 32 % in the annualized rate of exacerbations ( 1.44 vs. 2.12 , P = 0.04 ) and a reduction of 0.52 points with respect to asthma symptoms ( P = 0.004 ) , as measured on the Asthma Control Questionnaire 5 ( in which the minimal clinically important difference is 0.5 points ) .