Efficacy and Safety of Romiplostim Versus Placebo in Immune Thrombocytopenia: A Systematic Review and Meta-Analysis

BackgroundImmune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia and increased bleeding risk. Although first-line therapies such as corticosteroids and intravenous immunoglobulin provide initial benefit, many patients relapse or develop refractory disease. Romiplostim, a thrombopoietin receptor agonist, has emerged as an effective second-line therapy; however, evidence comparing its efficacy and safety with placebo across both pediatric and adult populations remains limited.MethodsA systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted following PRISMA guidelines (PROSPERO: CRD420261357179). PubMed, Scopus, Cochrane Library, and Google Scholar were searched up to March 2026. RCTs comparing romiplostim with placebo in ITP patients were included. A random-effects model was used to calculate mean differences (MD) and risk ratios (RR) with 95% confidence intervals (CI). Risk of bias was assessed using the Cochrane RoB 2 tool. Certainty of evidence was evaluated using the GRADE approach.ResultsNine RCTs (n=748) were included. Romiplostim significantly increased platelet counts at week 2 (MD 25.71; 95% CI 9.41-42.02), week 4 (MD 42.74; 95% CI 26.82-58.66), week 6 (MD 50.42; 95% CI 33.87-66.97), and week 8 (MD 49.14; 95% CI 20.45-77.83), with larger effects in adults. Platelet response rates were significantly higher with romiplostim (RR 6.10). The proportion achieving ≥20×10⁹/L increase improved (RR 3.23), and the need for rescue therapy decreased (RR 0.49). Adverse events were comparable between groups, with slight increases in myalgia and rash.ConclusionRomiplostim is an effective and well-tolerated therapy for ITP, significantly improving platelet outcomes and reducing rescue therapy requirements without major safety concerns.