Anagrelide in the management of essential thrombocythemia: a systemic review and meta-analysis

Essential thrombocythemia (ET) is a myeloproliferative neoplasm commonly treated with hydroxyurea, while anagrelide is a second-line option. Although anagrelide has thrombocyte-specific action, its comparative efficacy remains debated. This systematic review and meta-analysis aimed to measure platelet reduction, thromboembolic events, and adverse events.

A systematic search of PubMed, Cochrane, Web of Science, Scopus, EMBASE, and CINAHL databases up to October 6, 2024, was conducted following the PRISMA guidelines. Randomized controlled trials and cohort studies comparing anagrelide and hydroxyurea were included.

Six studies with 1555 participants met the inclusion criteria. Anagrelide was associated with significantly lower platelet counts than hydroxyurea (MD - 65.22; 95% CI - 80.78 to - 49.66; p < 0.01; I2 = 0%), but no significant difference in thrombohemorrhagic events (RR 1.34; 95% CI 1.10 to 1.62; p < 0.01; I2 = 12.5%). In single-arm analysis, JAK-positive patients showed a higher incidence of thrombotic events (0.23; 95% CI 0.14-0.35) than JAK-negative patients (0.10; 95% CI 0.08-0.13). Adverse event rates varied (RR 1.37; 95% CI 0.37-5.12; I2 = 94.9%).

Although comparative analyses against hydroxyurea have demonstrated the efficacy of anagrelide for platelet reduction in ET, its higher bleeding risk requires caution, especially in patients with risk factors. Further studies are needed to confirm long-term safety and refine dosing.