Population-based efficacy modeling of omalizumab in patients with severe allergic asthma inadequately controlled with standard therapy

Omalizumab, a recombinant humanized monoclonal antibody, is the first approved anti-immunoglobulin E (IgE) agent for the treatment of subjects with moderate to severe persistent allergic asthma that are inadequately controlled by the standard of care. The objective of this study was to quantitatively characterize relationships between serum free IgE and pulmonary function (as measured by forced expiratory volume in 1 s [FEV1]) as well as serum free IgE and airway inflammation (as measured by fractional exhaled nitric oxide [FeNO]) using population-based efficacy models. Data were collected from patients in the EXTRA trial who received omalizumab or placebo 150 to 375 mg subcutaneously every 2 or 4 weeks from week 0 to 48 with constant standard of care as background therapy. None of the covariates evaluated, including demographics, disease status, and baseline pharmacodynamic biomarkers, were significant in explaining the variability in the FEV1 or FeNO response to omalizumab. Results from the efficacy models further confirmed the current omalizumab dosing rationale based on the mean target free IgE level of 25 ng/ml and quantified the variability for the target. In addition, the resulting population models could be used to predict population FEV1 or FeNO response for omalizumab and/or other anti-IgE therapeutics for which PK-IgE models are constructed.

A randomized, placebo-controlled, dose-ranging study of single-dose omalizumab in patients with H1-antihistamine-refractory chronic idiopathic urticaria

BACKGROUND

Proof-of-concept studies with omalizumab in patients with chronic idiopathic urticaria (CIU) have shown significant decreases in mean urticaria activity scores (UASs).

OBJECTIVE

We sought to evaluate the efficacy and safety of omalizumab in patients with CIU who remain symptomatic despite concomitant H(1)-antihistamine therapy.

METHODS

This phase II, prospective, double-blind, placebo-controlled, dose-ranging study investigated omalizumab in patients aged 12 to 75 years in the United States and 18 to 75 years in Germany with a UAS over 7 days (UAS7) of 12 or greater despite antihistamine therapy. Patients were randomized 1:1:1:1 to receive a single subcutaneous dose of 75, 300, or 600 mg of omalizumab or placebo added to a stable dose of H(1)-antihistamine. The primary efficacy outcome was change from baseline to week 4 in UAS7. Patients were followed for an additional 12 weeks to monitor safety.

RESULTS

Ninety patients from the United States or Germany were enrolled. Both the 300-mg omalizumab group (-19.9 vs -6.9, P < .001) and the 600-mg omalizumab group (-14.6 vs -6.9, P = .047) showed greater improvement versus the placebo group in UAS7. No meaningful difference was observed for the 75-mg omalizumab group. Similar results were seen for key secondary end points of weekly hive and itch scores. Onset of effect occurred after 1 to 2 weeks. Omalizumab was well tolerated, and the incidence of adverse events was similar across treatment groups.

CONCLUSION

This study demonstrated that a fixed dose of 300 or 600 mg of omalizumab provides rapid and effective treatment of CIU in patients who are symptomatic despite treatment with H(1)-antihistamines.

Omalizumab in severe allergic asthma inadequately controlled with standard therapy: a randomized trial

BACKGROUND

Inhaled corticosteroids (ICS) and long-acting β(2)-agonists (LABAs) are recommended in patients with asthma that is not well-controlled; however, many patients continue to have inadequately controlled asthma despite this therapy.

OBJECTIVE

To evaluate the efficacy and safety of omalizumab in patients with inadequately controlled severe asthma who are receiving high-dose ICS and LABAs, with or without additional controller therapy.

DESIGN

Prospective, multicenter, randomized, parallel-group, double-blind, placebo-controlled trial. (ClinicalTrials.gov registration number: NCT00314575).

SETTING

193 investigational sites in the United States and 4 sites in Canada.

PATIENTS

850 patients aged 12 to 75 years who had inadequately controlled asthma despite treatment with high-dose ICS plus LABAs, with or without other controllers.

INTERVENTION

Omalizumab (n = 427) or placebo (n = 423) was added to existing medication regimens for 48 weeks.

MEASUREMENTS

The primary end point was the rate of protocol-defined exacerbations over the study period. Secondary efficacy end points included the change from baseline to week 48 in mean daily number of puffs of albuterol, mean total asthma symptom score, and mean overall score on the standardized version of the Asthma Quality of Life Questionnaire (AQLQ[S]). Safety end points included the frequency and severity of treatment-emergent adverse events.

RESULTS

During 48 weeks, the rate of protocol-defined asthma exacerbations was significantly reduced for omalizumab compared with placebo (0.66 vs. 0.88 per patient; P = 0.006), representing a 25% relative reduction (incidence rate ratio, 0.75 [95% CI, 0.61 to 0.92]). Omalizumab improved mean AQLQ(S) scores (0.29 point [CI, 0.15 to 0.43]), reduced mean daily albuterol puffs (-0.27 puff/d [CI, -0.49 to -0.04 puff/d]), and decreased mean asthma symptom score (-0.26 [CI, -0.42 to -0.10]) compared with placebo during the 48-week study period. The incidence of adverse events (80.4% vs. 79.5%) and serious adverse events (9.3% vs. 10.5%) were similar in the omalizumab and placebo groups, respectively.

LIMITATIONS

The results are limited by early patient discontinuation (20.8%). The study was not powered to detect rare safety events or the treatment effect in the oral corticosteroid subgroup.

CONCLUSION

In this study, omalizumab provided additional clinical benefit for patients with severe allergic asthma that is inadequately controlled with high-dose ICS and LABA therapy.

PRIMARY FUNDING SOURCE

Genentech and Novartis Pharmaceuticals.