https://orcid.org/0000-0002-9419-2415
Abstract
Background
Omalizumab is a treatment option for pediatric and adult patients with moderate to severe allergic asthma poorly controlled with standard inhaled therapies. Clinical trials and observational studies have demonstrated the efficacy of omalizumab. There is limited real-world evidence on the characteristics and treatment patterns of Canadian asthma patients receiving omalizumab.
Objective
We profiled Canadian omalizumab users to estimate time to omalizumab discontinuation and to assess changes in concurrent medication usage before, during, and after therapy.
Methods
This was a retrospective, observational, cohort study that analyzed data from Canadian prescription claims databases. An algorithm was used to select naïve users of omalizumab with an inferred diagnosis of GINA 5-asthma who made a claim for omalizumab from February 1, 2007, to June 2, 2015. Demographic and baseline characteristics were assessed at index. Outcomes examined over the analysis period included (i) daily omalizumab dose per patient and per claim; (ii) omalizumab discontinuation (defined as ≥100-day gap in making omalizumab claims) and its potential predictors (ie, age, sex, province of residence, drug insurer; assessed by Cox Proportional Hazards Model); and (iii) for patients who discontinued omalizumab, changes in concurrent medication usage before, during, and 6 months after omalizumab usage.
Results
The final study cohort consisted of 1160 patients (mean age: 45.8 ± 15.2 years; 64.7% female). During the first year of omalizumab therapy, 29.5% of patients discontinued treatment. The singular characteristic that predicted omalizumab discontinuation with statistical significance was age group (20‒34 years vs 12‒19 years; hazard ratio 1.75, 95% confidence interval 1.11–2.76; P<0.05). There were significant reductions in the use of some concurrent inhaled and oral asthma medications during and/or after omalizumab use (P<0.05).
Conclusion
Nearly one-third of patients who initiated omalizumab in Canada for refractory, moderate to severe allergic asthma discontinued treatment during the first year.
Abbreviations
CI, confidence interval; COPD, chronic obstructive pulmonary disease; CTS, Canadian Thoracic Society; GINA, Global Initiative for Asthma; HR, hazard ratio; ICS, inhaled corticosteroid; Ig, immunoglobulin; LABA, long-acting β2-agonist; LAMA, long-acting muscarinic antagonist; LTRA, leukotriene receptor antagonist; PDE4, phosphodiesterase-4 inhibitor; OCS, oral corticosteroid; OR, odds ratio; RCT, randomized controlled trial; SABA, short-acting β2-agonist; SD, standard deviation.
Ethics Approval
Institutional Review Board approval was not required since this is a prescription claims-level study using anonymized data.
Acknowledgments
The authors wish to acknowledge Ardeane Healthcare Solutions and medical writer, Christina Clark, for their assistance in the preparation of this paper. An abstract of this paper was presented at the 2018 Canadian Society of Allergy and Clinical Immunology Annual Scientific Meeting as a poster presentation. The poster’s abstract was published in the Proceedings of the Canadian Society of Allergy and Clinical Immunology Annual Scientific Meeting 2018. Allergy Asthma Clin Immunol 2019;15 (Suppl 1):A6 (available at https://aacijournal.biomedcentral.com/articles/10.1186/s13223-019-0322-9).
Author Contributions
All authors were involved in the conception and design of the study. Atif Kukaswadia, Jelena Ivanovic and Aren Fischer were responsible for the acquisition and analysis of data. All authors contributed to the interpretation of data, revised the manuscript for important intellectual content, approved the final version to be published, and agreed to be accountable for all aspects of this work.
Disclosure
Jason K. Lee is affiliated with Evidence Based Medical Educator Inc and Urticaria Canada. He reports personal fees from AstraZeneca during the conduct of this study, and outside of this submitted work. He also reports grants from GlaxoSmithKline and Shire; grants and personal fees from Novartis, Sanofi, Genzyme, Genentech, Roche, and Pediapharm; personal fees from ALK, Aralez, Merck and Trudell Medical; and grants, personal and application development fees from Stallergens. Atif Kukaswadia and Jelena Ivanovic are current employees of IQVIA, while Aren Fischer, is a former IQVIA employee, all of whom collaborated on this study as consultants paid by AstraZeneca. Suvina Amin, Michelle Erdmann, and Alain Gendron, are employees of AstraZeneca. The authors report no other conflicts of interest in this work.