Darbepoetin alfa for the treatment of anemia in myelodysplastic syndromes: a post-marketing surveillance study in Japan

Abstract Post-marketing surveillance was conducted in Japan (2015–2024, UMIN000056049) to evaluate the long-term safety and effectiveness of darbepoetin alfa for anemia with myelodysplastic syndromes (MDS) for 5 years after treatment initiation. Among 1834 patients (median age: 79.0 years), the distribution of International Prognostic Scoring System (IPSS) risk categories was: Low, 39.3%; Intermediate-1, 45.1%; Intermediate-2, 7.7%; and High, 2.8%. The median (range) administration duration, dosing interval, and weekly dose were 330.0 (1–1863) days, 1.7 (0.2–41.5) weeks, and 240.0 (30.0–250.0) µg, respectively. Treatment discontinuation reasons included inadequate response (36.9%) and adverse events (AEs) (31.2%). AEs were reported in 75.1% and included pneumonia (16.6%) and transformation to acute myeloid leukemia (9.0%). Mean hemoglobin concentration (n = 1821) increased from 7.6 g/dL at baseline to > 9.0 g/dL after 52 weeks. Red blood cell transfusion volume decreased by ≥ 50% compared with baseline in 65.2% of patients. In transfusion-dependent patients (n = 909), the highest transfusion-independence rate was 40.9% at year 4–5. Five-year overall/leukemia-free survival rates (n = 1826/1814) by IPSS risk group were: Low, 49.5%/48.8%, Intermediate-1, 31.1%/30.2%, Intermediate-2, 11.9%/10.4%, and High, 0%/0%. Poor prognostic factors for MDS were IPSS risk category, age, chromosomal abnormalities, and platelet count. No new safety or effectiveness concerns were identified. Trial registration: University Hospital Medical Information Network; study ID: UMIN000056049.