Affiliation:
1. Faculty of Medicine University of Ottawa Ottawa Ontario Canada
2. Faculty of Health Sciences McMaster University Hamilton Ontario Canada
3. Department of Biomedical Sciences University of Guelph Guelph Ontario Canada
4. Department of Health Research Methods, Evidence, and Impact McMaster University Hamilton Ontario Canada
5. Department of Medicine McMaster University Hamilton Ontario Canada
Abstract
AbstractImmune thrombocytopenic purpura (ITP) is an immune disorder characterized by thrombocytopenia. Fostamatinib is an orally administered spleen tyrosine kinase inhibitor intended to treat refractory ITP. To evaluate the efficacy and safety of fostamatinib as a subsequent‐line therapy for ITP in adults. We searched four electronic databases for primary studies of any design. Primary efficacy outcomes included proportions of patients achieving overall (≥30 × 109 cells/L), partial (≥50 × 109 cells/L), and stable (as defined in original studies) platelet response. Safety outcomes included rescue medication use and other adverse events. We used narrative synthesis and Mantel–Haenszel random effect meta‐analysis to summarize results. Our systematic review included 11 studies for analyses (n = 722). Weighted mean proportions of patients achieving overall, partial, and stable responses with fostamatinib treatment were 0.70 [0.62, 0.76], 0.48 [0.36, 0.61], and 0.28 [0.16, 0.44], respectively. Fostamatinib was favored over placebo for partial (relative risk [RR] = 3.04, 95% confidence interval [CI] [1.53, 6.06]) and stable (RR = 6.43, 95% CI [1.58, 26.23]) responses. Patients on fostamatinib required less rescue medication and were more likely to experience hypertension. Fostamatinib is a viable subsequent‐line therapy option for refractory ITP. Given the heterogeneous data and large number of small studies, these results should be interpreted cautiously.