MedicalResearch.com Interview with:
Dr. Julia Lewis, MD, Lead Investigator
Nephrologist and Professor of Medicine
Vanderbilt University Medical Center
Medical Research: What is the background for this study? What are the main findings?
Dr. Lewis: The 48-week Open Label Extension (OLE) study for Auryxia™ (ferric citrate) was conducted to determine long term safety following the Phase 3 52-week active-control period. The study also evaluated changes in serum phosphorus, transferrin saturation (TSAT), serum ferritin, hemoglobin, hematocrit and additional parameters, as well as intravenous (IV) iron and erythropoiesis-stimulating agent (ESA) usage.
In the OLE study, Auryxia demonstrated long-term safety in dialysis-dependent chronic kidney disease (CKD) patients. The results were consistent with those seen in the published pivotal Phase 3 trial.
The study demonstrated that the adverse events (AE’s) profile of Auryxia was similar to that seen in the Phase 3 52-week active-control period. AEs occurred in 142 patients treated with Auryxia. They were primarily non-serious gastrointestinal (GI) – related AE’s, including diarrhea, nausea, vomiting and constipation. Serious adverse events occurred in 75 patients, though none were related to Auryxia. In addition, there were no clinically or statistically significant differences in liver enzymes or aluminum levels observed from baseline to the end of the 48 weeks.
Similar to the original trial, we witnessed excellent phosphorus control with the drug, along with an increase and then a plateau in serum ferritin and TSAT levels with Auryxia. The plateauing of serum ferritin and TSAT further supports iron absorption is highly regulated by the gastrointestinal track as seen in the 52-week active control period. This suggests that the body absorbs iron as needed for effective erythropoiesis.
Additionally, iron store increases from ferric citrate resulted in, by the end of the extension study, 85% of subjects not using any IV iron.
We presented this data at the 2014 American Society of Nephrology Meeting. The abstract can be found online at www.asn-online.org.