Influence of prolonged treatment with omalizumab on the development of solid epithelial cancer in patients with atopic asthma and chronic idiopathic urticaria: A systematic review and meta-analysis

Objective We investigated whether prolonged treatment with omalizumab influences development or progression of solid epithelial cancer in patients with atopic asthma or chronic idiopathic urticaria. Design Systematic review and meta-analysis of intervention and observational studies. Randomized controlled trials were assessed for risk of bias using the Cochrane Risk of Bias tool, comparative observational studies were assessed using the Newcastle-Ottawa Scale, and non-comparative observational studies were assessed using the Joanna Briggs Institute Checklist for Prevalence Studies. Data sources We searched MEDLINE, EMBASE, Cochrane Library and grey literature for eligible studies to November 2017. All searches were updated in January 2019. Eligibility criteria for included studies Randomized, quasi-randomized, controlled clinical trials and observational studies were included if they involved patients >= 12 years with moderate-to-severe persistent asthma or chronic idiopathic urticaria treated with omalizumab for >= 40 weeks. Eligible comparators included standard of care, placebo, cromoglycate or no treatment. Results One hundred and sixty seven unique studies were eligible for inclusion; however, only twelve (7.2%, n = 11 758) reported any outcome of interest, none of which involved patients with urticaria. 195 cancer events were reported. We found no statistically significant increase in the odds of study-emergent solid epithelial cancer in patients randomized to long-term treatment with omalizumab compared to standard of care (Peto OR: 0.65, 95% CI: 0.11, 3.74, I-2 = 41%). Less than one per cent of participants of non-comparative observational studies (n = 2350) were diagnosed with a solid epithelial tumour (meta-proportion: 0.86% [95% CI: 0.24, 1.86%, I-2 = 56%]). In the only comparative observational study reporting on cancer, the proportion of study-emergent solid epithelial tumour events was nearly identical in both study groups (omalizumab: 2.3%, standard of care: 2.2%). Conclusions There is insufficient evidence to determine whether long-term treatment with omalizumab influences development or progression of solid epithelial cancer in these patient populations. PROSPERO registration # CRD 42018082211.