A Study Evaluating the Persistency of Response With or Without Xolair (Omalizumab) After Long-term Therapy

The treatment designation for participants who reached the primary efficacy endpoint (1 protocol-defined severe asthma exacerbation) was unblinded to allow appropriate clinical intervention. Participants who had their treatment designation unblinded remained in the study for ongoing evaluation of safety and were allowed to continue on study drug known to be Xolair (or to start study drug known to be Xolair if they were in the placebo group).