At the end of 12 weeks , there were significantly greater percentages of responders in groups given medium-dose OBS ( 52.6 % , P = .0092 ) and high-dose OBS ( 47.1 % , P = .0174 ) than in the group given placebo ( 5.6 % ) ; there was no significant difference in percentages of responders between the low-dose OBS ( 11.8 % ) and placebo groups ( P = .5282 ) .