PURPOSE: Omalizumab has been shown to be an effective treatment for difficult to control asthma in numerous clinical trials. Real-world experience with a drug does not always correlate with clinical trials that may only represent a select population based on inclusion criteria. The purpose of this study is to determine if the efficacy of Omalizumab in clinical practice correlates with clinical trials, and to determine if pre-treatment criteria can predict response to therapy.
METHODS: The records of 38 consecutive patients treated with Omalizumab at a pulmonary and allergy specialty practice were reviewed. All patients met the accepted criteria for this treatment. Outcome was determined by the global assessment of the treating physician; “much better”, “better”, “slightly better” or “no better”. Those assessed as “much better” or “better” were classified as responders and those assessed as “slightly better” or “no better” were considered nonresponders. In addition, pre-treatment variables including age, FEV-1, IgE level and frequency of exacerbations (annualized for the period of observation prior to initiation of Omalizumab) were correlated with outcome.
RESULTS: Overall 58% of patients were classified as responders. Response rate by age: 20–39 y/o (n=4)=75%; 40–59 y/o (n=25)=56%; 60–79 y/o (n=9)=56%. Response rate by IgE: 30–99 (n=12)=67%; 100–199(n=14)=50%; 200–499 (n=11)=55%. Response rate by FEV-1 (% predicted): >79 (n=10)=80%; 60–79 (n=16)=44%; 40–59 (n=8)=50%; <40 (n=4)=75%.Response rate by exacerbation frequency: >=1 exacerbation per year(n=25)=68%; <1 (n=13)=38%.
CONCLUSION: Response rates based on physician assessment in published trials range from 53.1% to 68.5%. The response rate of 58% is within this range confirming that real-world experience correlates with clinical trial data. In terms of the predictive value of pre-treatment criteria, age, IgE and FEV-1 do not appear to predict response to treatment. Exacerbation frequency may be more useful with those having <1 exacerbation per year responding only 38% of the time.
CLINICAL IMPLICATIONS: Until larger prospective trials are done, the only reliable predictor of Omalizumab response is a therapeutic trial in appropriate patients.
DISCLOSURE: Robert Sussman, No Product/Research Disclosure Information; Grant monies (from industry related sources) Clinical research: Glaxo, BI, Intermune, Actelion, Novartis, Astra-Zeneca, Altana, Dey; Consultant fee, speaker bureau, advisory committee, etc. Speakers bureau: Glaxo, BI, Novartis, Genetec, Pfizer, Schering, Oscient, Sepracor