Persistency of response to omalizumab therapy in severe allergic (IgE-mediated) asthma

The physician's global evaluation of treatment effectiveness (GETE) at 16 weeks has been shown to be the most effective assessment of response to omalizumab (XOLAIR®). This randomized, open-label, parallel-group study evaluated the persistency of treatment responder classification in patients receiving omalizumab added to optimized asthma therapy (OAT).

Patients (12-75 years, n = 400) with severe allergic asthma, uncontrolled despite Global Initiative for Asthma 2004 Step 4 therapy, received OAT and omalizumab (n = 272) or OAT (n = 128) for 32 weeks. Response or nonresponse was evaluated at Weeks 16 and 32. Response was defined as an investigator's (physician's) GETE rating of excellent or good; nonresponse was defined as a rating of moderate, poor or worsening.

Three hundred and forty-nine patients had GETE ratings available at Weeks 16 and 32 (omalizumab n = 258, OAT n = 91). Omalizumab responders of about 171/187 (91.4%)and 44/71 (62.0%) omalizumab nonresponders at Week 16 persisted as responders or nonresponders at Week 32. The investigator's GETE at Week 16 predicted persistency of response or nonresponse to omalizumab at Week 32 for 83.3% (215/258) of patients. OAT patients showed a lower persistency of response (18/28 [64.3%]) and a higher persistency of nonresponse (57/63 [90.5%]) than omalizumab patients. Excellent and good GETE ratings in omalizumab-treated patients were reflected by improvements in exacerbation rates (P < 0.001), severe exacerbation rates (P = 0.023), hospitalizations (P = 0.003), total emergency visits (P = 0.026) and Asthma Control Questionnaire overall score (P < 0.001).

Response to omalizumab, as assessed by a physician's GETE at 16 weeks, is an effective predictor of continuing persistent response to omalizumab for the majority of patients.