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Background Vadadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis. Methods The efficacy and safety of vadadustat, compared with darbepoetin alfa, was determined in a Phase 3 double-blind study in Japanese anemic patients on hemodialysis. Patients receiving erythropoiesis-stimulating agents (ESAs) were randomized and switched to either vadadustat or darbepoetin alfa for 52 weeks. Doses were adjusted to maintain a hemoglobin (Hb) level of 10.0–12.0 g/dL. The primary endpoint was average Hb level at Weeks 20 and 24. Results Of the 323 randomized patients, 120 and 135 completed the 52-week treatment period in the vadadustat and darbepoetin alfa groups, respectively. The average Hb levels at Weeks 20 and 24 [least square mean (LSM) and 95% confidence interval (CI)] were 10.61 (10.45–10.76) and 10.65 (10.50–10.80) g/dL in the vadadustat and darbepoetin alfa groups, respectively, demonstrating vadadustat’s noninferiority to darbepoetin alfa (difference: −0.05 g/dL; 95% CI −0.26 to 0.17). In both groups, the mean Hb levels were maintained within the target range for 52 weeks. Furthermore, irrespective of patient backgrounds, the LSMs of Hb at Week 52 were within the target range. The most common adverse events were nasopharyngitis, diarrhea and shunt stenosis, which occurred at similar frequencies in both groups. No new safety concerns were identified. Conclusions Vadadustat was as well-tolerated and effective as darbepoetin alfa in maintaining Hb levels within the target range. The findings suggest that vadadustat can be an alternative to ESA in the management of anemia in Japanese hemodialysis patients receiving ESA (ClinicalTrials.gov, NCT03439137)., Graphical Abstract

Background and Aims Vadadustat is a small-molecule inhibitor of hypoxia-inducible factor prolyl hydroxylases under development to treat anemia associated with chronic kidney disease (CKD). The vadadustat phase 3 program includes four efficacy and cardiovascular safety outcome trials of vadadustat versus the erythropoiesis-stimulating agent (ESA) darbepoetin alfa. Here we describe detailed results on hematologic efficacy in two phase 3, randomized trials (the PRO2TECT trials) in adult patients with non–dialysis-dependent (NDD) CKD and anemia, in which vadadustat met prespecified noninferiority criteria compared to darbepoetin alfa, with respect to hematologic efficacy (correction/maintenance of hemoglobin [Hb] target concentrations). Method The mean screening Hb level for the ESA-untreated NDD-CKD trial (NCT02648347) had to be Results A total of 3,476 patients (1751 ESA-untreated and 1725 ESA-treated) were randomized 1:1 to vadadustat or darbepoetin alfa. In both trials, vadadustat was noninferior to darbepoetin alfa with regard to the difference of mean change in Hb concentrations between baseline and PEP, as well as between baseline and SEP. The respective proportions of patients (vadadustat vs. darbepoetin alfa) with an average Hb value within the geography-specific target range in the PEP and SEP were 50.4% versus 50.2% and 43.1% versus 43.5% in the ESA-untreated trial and 60.1% versus 60.7% and 50.7% versus 49.0% in the ESA-treated trial. The proportion of patients (vadadustat vs darbepoetin alfa) who achieved an Hb increase >1.0 g/dL from baseline to week 52 was assessed only for the ESA-untreated trial and was 87.7% (95% CI: 85.4%, 89.8%) for vadadustat versus 88.0% (95% CI: 85.6%, 90.0%) for darbepoetin alfa. Hematologic parameters at time points within the PEP and SEP are presented in Table 1. In both the ESA-untreated and ESA-treated trials, the reticulocyte count trended up from baseline through week 52 for vadadustat and trended down from baseline for darbepoetin alfa. Trends in erythrocyte mean corpuscular volume and erythrocyte mean corpuscular Hb were largely unremarkable by week 52 in both treatment groups. Conclusion Vadadustat demonstrated similar profiles across erythrocyte parameters compared with darbepoetin alfa in the treatment of adults with anemia in CKD not on dialysis, whether ESA-untreated or ESA-treated at study entry.

Background and Aims Vadadustat is a small-molecule inhibitor of hypoxia-inducible factor prolyl hydroxylase being developed for treatment of anemia associated with chronic kidney disease (CKD). The vadadustat phase 3 program includes four efficacy and cardiovascular safety outcome trials of vadadustat versus the erythropoiesis-stimulating agent (ESA) darbepoetin alfa. Here we describe detailed results on hematologic efficacy in two of the four phase 3, randomized, open-label, sponsor-blind trials (the INNO2VATE trials) in adult patients with dialysis-dependent (DD) CKD and anemia, where vadadustat met prespecified noninferiority criteria compared with darbepoetin alfa with respect to cardiovascular safety and correction/maintenance of hemoglobin (Hb) target concentrations. Method The mean screening Hb range for the incident DD-CKD trial (NCT02865850) was 8.0-11.0 g/dL; for the prevalent DD-CKD trial (NCT02892149), it was 8.0-11.0 g/dL in the United States (US) and 9.0-12.0 g/dL for non-US. Patients in the incident and prevalent DD-CKD trials had initiated dialysis within 12 weeks with established ESA treatment prior to screening, respectively. Vadadustat starting dose was 300 mg/day for all patients, whereas initial darbepoetin alfa dose depended on each patient’s prior dose or product label. Both vadadustat and darbepoetin alfa doses were titrated according to prespecified dosing algorithms to achieve target Hb concentrations (US: 10-11 g/dL; non-US: 10-12 g/dL) during the primary evaluation period (PEP; weeks 24-36) and the secondary evaluation period (SEP; weeks 40-52). Herein, we present topline results from PEP and SEP endpoints, as well as other, more detailed hematologic erythrocyte parameters. Results A total of 3923 patients (369 with incident DD-CKD and 3554 with prevalent DD-CKD) were randomized 1:1 to vadadustat or darbepoetin alfa. Vadadustat was noninferior to darbepoetin alfa in achieving target-range Hb concentrations (primary efficacy endpoint) among patients who were new to, or established on, dialysis. The respective proportions of patients (vadadustat vs. darbepoetin alfa) with an average Hb value within the geography-specific target range in the PEP and SEP were 43.6% versus 56.9% and 39.8% versus 41.0% in the incident trial and 49.2% versus 53.2% and 44.3% versus 50.9% in the prevalent dialysis trial. The proportion of patients who achieved an Hb increase >1.0 g/dL from baseline to week 52 was assessed only for the incident trial and was 84.0% (95% CI: 77.8%, 89.0%) for vadadustat versus 89.9% (95% CI: 84.7%, 93.8%) for darbepoetin alfa. Hematologic erythrocyte parameters at time points within the PEP and SEP are presented in Table 1. In the incident trial, reticulocyte count was slightly increased from baseline at 28 and 52 weeks for vadadustat, whereas for darbepoetin alfa, reticulocyte count was slightly decreased or unchanged in both trials. Erythrocyte mean corpuscular volume and erythrocyte mean corpuscular Hb showed increases by week 52 for both groups. Conclusion Vadadustat demonstrated similar profiles across erythrocyte parameters compared with darbepoetin alfa in the treatment of anemia associated with CKD in adults in both incident dialysis and prevalent dialysis settings.

Background Vadadustat, an inhibitor of hypoxia-inducible factor prolyl-4-hydroxylase domain dioxygenases, is an oral investigational agent in development for the treatment of anemia secondary to chronic kidney disease. Methods In this open-label Phase 2 trial, vadadustat was evaluated in 94 subjects receiving hemodialysis, previously maintained on epoetin alfa. Subjects were sequentially assigned to one of three vadadustat dose cohorts by starting dose: 300 mg once daily (QD), 450 mg QD or 450 mg thrice weekly (TIW). The primary endpoint was mean hemoglobin (Hb) change from pre-baseline average to midtrial (Weeks 7–8) and end-of-trial (Weeks 15–16) and was analyzed using available data (no imputation). Results Overall, 80, 73 and 68% of subjects in the 300 mg QD, 450 mg QD, and 450 mg TIW dose cohorts respectively, completed the study. For all dose cohorts no statistically significant mean change in Hb from pre-baseline average was observed, and mean Hb concentrations—analyzed using available data—remained stable at mid- and end-of-trial. There was one subject with an Hb excursion >13 g/dL. Overall, 83% of subjects experienced an adverse event (AE); the proportion of subjects who experienced at least one AE was similar among the three dose cohorts. The most frequently reported AEs were nausea (11.7%), diarrhea (10.6%) and vomiting (9.6%). No deaths occurred during the study. No serious AEs were attributed to vadadustat. Conclusions Vadadustat maintained mean Hb concentrations in subjects on hemodialysis previously receiving epoetin. These data support further investigation of vadadustat to assess its long-term safety and efficacy in subjects on hemodialysis.