Presentation (CTI)

OBJECTIVES: This review aims to identify and summarize peer-reviewed literature to better understand the survival, complications, disease progression, treatment patterns, and unmet needs associated with essential thrombocythemia (ET).
METHODS: A structured literature search was conducted in MEDLINE^® and Embase^® databases (January 01, 2011-October 05, 2023). The studies were screened based on the PICOTS criteria.
RESULTS: A total 96 studies were analyzed, reporting on survival, complications, disease transformation, treatment pattern including adherence/discontinuation/switch, and unmet needs in ET. Reported median overall survival (OS) for ET patients ranged from 12.0 (median-follow-up:4.1 years) to 19.8 years (median-follow-up:17.3 years). The estimated 5- and 10-year OS rates ranged from 76.0%-93.6% and 58.0%-91.0%, respectively. Cumulative incidences of thrombotic events at 5, 10, and 15 years were estimated as 5.7%-15.2%, 11.4%-26.3%, and 22.0%-35.0%, respectively, with a median time from diagnosis to first event of 4.2-4.6 years. Arterial and venous thromboses were reported in 0.3% (mean-follow-up:3.8years)-36.0% (median-follow-up:9years) and 0.6% (median-follow-up:4.7years)-8.4% (median follow-up:9years) of patients, respectively. Bleeding events were reported in 4.4% (median-follow-up:4.1years)-18.6% (median-follow-up:3.0 years) of patients, with a median time from diagnosis to first event of approximately 3.25 years. The 10-year cumulative incidence of progression to myelofibrosis was 5.8%, while that for progression to acute myeloid leukemia was 0.7%-1.5%. Hydroxyurea was the predominant first-line treatment (53.8%-93.3%). Among patients who continued hydroxyurea, 35.5% did not achieve desired platelet counts, 25% had persistent symptoms, and 1.2% experienced thrombotic events. Estimated discontinuation rates of hydroxyurea ranged from 10.9%-22.0%. Reported reasons for discontinuation include intolerance (35.4%) and resistance (23.8%). An estimated 65.9% of patients who discontinued hydroxyurea did not receive subsequent treatment. 19.4% of patients were estimated to switch from hydroxyurea due to intolerance (27.9%) and lack of efficacy (12.1%).
CONCLUSIONS: Results highlight the significant clinical burden of ET, and an unmet need associated with hydroxyurea. There is need for innovative therapy to achieve improved disease management.