Phosphate binders do not appear to substantially affect the efficacy of the hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI) daprodustat, according to preliminary study findings presented at Kidney Week 2020 Reimagined, a virtual meeting sponsored by the American Society of Nephrology.

In the GSK PHI113633 trial (NCT01977482) of 216 patients receiving hemodialysis, 77% of the daprodustat group and 85% of the control group (receiving human recombinant erythropoietin) were taking phosphate binders at baseline and had comparable phosphate control (mean serum phosphate 1.76 vs 1.67 mmol/L, respectively). Baseline hemoglobin (Hb) did not differ meaningfully between the HIF-PHI and control groups (10.39 g/dL daprodustat vs 10.55 g/dL placebo), including the subsets taking phosphate binders (10.38 vs 10.48 g/dL, respectively).

At 24 weeks, achieved Hb differed only slightly among daprodustat patients taking and not taking phosphate binders: 10.40 g/dL for the phosphate binder group vs 10.79 g/dL the patients not taking phosphate binders, Borut Cizman, MD, and colleagues from GlaxoSmithKline in Collegeville, Pennsylvania, reported. The final median dose of daprodustat was 6 mg, regardless of whether daprodustat users were taking calcium and/or noncalcium phosphate binders, or no binders.

“These results suggest that [phosphate binder] use does not have a major impact on [hemoglobin] values during the 24-week study,” Dr Cizman’s team stated. “Results of ASCEND-D, an ongoing, phase 3 dialysis study of daprodustat compared with conventional treatment, are awaited to confirm these initial observations.”


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Disclosure: This clinical trial was supported by GlaxoSmithKline. Please see the original reference for a full list of authors’ disclosures.

References

  1. Cizman B, Meadowcroft, AM, Biswas N, Sprys M, Cobitz AR. Daprodustat interaction with phosphate binders has minimal impact on hemoglobin values in hemodialysis population. Presented at: Kidney Week Reimagined; October 19-25, 2020. Abstract: PO0293.
  2. Meadowcroft AM, Cizman B, Holdstock L, et al. Daprodustat for anemia: a 24-week, open-label, randomized controlled trial in participants on hemodialysis. Clin Kid J. 12(1):139–148. doi:10.1093/ckj/sfy014