Fibrogen Presents CKD-ESRD Hemoglobin Correction Data

FibroGen, Inc. presented data from a China-based Phase II study of roxadustat (FG-4592), its first-in-class oral compound for the treatment of anemia associated with chronic kidney disease (CKD) and end-stage renal disease (ESRD), in an oral session at the 2013 American Society of Nephrology (ASN) Kidney Week in Atlanta, Georgia.

Roxadustat is an orally administered, small molecule inhibitor of hypoxia-inducible factor (HIF) prolyl hydroxylase. HIF is a protein that responds to oxygen changes in the cellular environment and meets the body’s demands for oxygen by inducing erythropoiesis, the process by which red blood cells are produced and iron is incorporated into hemoglobin (Hb).

The randomized, double-blind, placebo-controlled study was designed to evaluate the efficacy, safety, and tolerability of roxadustat in the correction of anemia in patients (N=91) with chronic kidney disease who had not received dialysis treatment, were not receiving erythropoiesis-stimulating agents (ESAs), and had Hb levels less than 10 g/dL. The correction study randomized patients 2:1 between roxadustat and placebo for eight weeks of dosing, and included a low-dose cohort and high-dose cohort. Intravenous (IV) iron was not allowed. The study also evaluated iron utilization, changes in serum lipids, and other biomarkers during treatment with roxadustat.

Data from this study suggest that roxadustat effectively corrected hemoglobin levels in anemic CKD patients in a dose-dependent manner as compared to placebo, and did so in the absence of IV iron supplementation regardless of degree of iron repletion at baseline. At the end of the eight-week treatment period, subjects showed mean maximum Hb increases from baseline of 2.6 g/dL in the high dose cohort and 1.8 g/dL in the low dose cohort, as compared to 0.7 g/dL in the placebo group from mean baseline Hb of 8.8 g/dL, 8.8 g/dL, and 8.9 g/dL in the high dose, low dose, and placebo groups, respectively. 87% of patients in the high-dose cohort, 80% of patients in the low-dose cohort, and 23% of patients in the placebo group experienced a hemoglobin increase of 1 g/dL or greater from baseline. Similarly, 71% of patients in the high-dose cohort, 50% of patients in the low-dose cohort, and 3% of patients in the placebo group achieved target hemoglobin of 11 g/dL or greater. Serum iron levels remained stable in subjects randomized to roxadustat while the subjects underwent brisk erythropoiesis.

Study data also suggest that roxadustat may lower cholesterol. Dyslipidemia is highly prevalent in chronic kidney disease patients and a major cardiovascular risk factor in this population. Patients treated with roxadustat experienced a statistically significant reduction in total cholesterol and low-density lipoprotein (LDL) cholesterol at the end of the treatment period. The relative proportion of high density lipoprotein (HDL) cholesterol to LDL cholesterol increased significantly. Overall LDL cholesterol levels declined by a mean of 26% and median of 23% from a mean baseline value of 103 mg/dL.

Roxadustat was well tolerated by patients in the study with incidence of adverse events similar across all groups. In contrast to the exacerbation of hypertension observed in studies in which patients received currently available ESA therapies, subjects who received roxadustat in the present study showed small decreases in blood pressure that were similar to blood pressure changes in the placebo group. No cardiovascular serious adverse events were reported in patients treated with roxadustat.

The efficacy and safety of roxadustat are currently being investigated in a global Phase III development program.