The comparison of four hypoxia-inducible factor prolyl hydroxylase inhibitors on drug potency and cost for treatment in patients with renal anemia.

Background: Five hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) have been approved for marketing in Japan. However, marked differences exist in terms of drug potency, dose requirement, and pharmacokinetics.

Methods: The primary evaluation in this study was the changes in hemoglobin levels, dose escalation, drug potency, and cost among HIF-PHIs, 3 months after the initiation of treatment.

Results: All patients treated with HIF-PHI between August 2020 and December 2023 were enrolled in this study. In total, 124 patients were administered daprodustat (N = 37), enarodustat (N = 44), molidustat (N = 13), or vadadustat (N = 30). The mean hemoglobin levels of daprodustat, enarodustat, molidustat, and vadadustat at 3 months were 11.7 g/dL, 11.8 g/dL, 12.2 g/dL, and 11.3 g/dL, respectively. At 3 months, the mean doses of daprodustat, enarodustat, molidustat, and vadadustat increased by 110%, 177%, 125%, and 152%, respectively, from the initial dose. The HIF-PHI potency indices (HPI) of daprodustat, enarodustat, molidustat, and vadadustat at 3 months were 0.168, 0.307, 0.184, and 0.254, respectively. At 3 months, the mean daily costs of daprodustat, enarodustat, molidustat, and vadadustat were JPY 345, JPY 434, JPY 206, and JPY 565, respectively.

Conclusion: The difference in dose escalation for anemia treatment among HIF-PHIs is due to differences in drug potency, where the HPI significantly differs among HIF-PHIs. The disparity between the HPI and the cost of the initial dose accounts for the variance in the daily costs of renal anemia treatment among HIF-PHIs.