The annual prevalence of end-stage renal disease (ESRD) in the US is approximately 500,000, and is growing every year because of the obesity epidemic. ESRD occurs at the later stages of chronic kidney disease, which is primarily associated with Type 2 diabetes and hypertension. The role of the kidneys is largely hinged to blood filtering and subsequent excretion of waste products and toxins. The central hormonal feature of the kidneys is the renin-angiotensin system, which in the presence of chronic kidney disease (CKD) leads to a variety of symptoms, including hypertension, edema, potassium accumulation, decrease of erythropoietin, urea accumulation, accumulation of phosphates, vitamin D3 deficiency and subsequent low calcium, acidosis, and accelerated osteoarthritis and cardiovascular disease.
One of the most common hallmarks of CKD and ESRD, is anemia, a reduction in oxygen-carrying red blood cells (RBCs). Anemia in ESRD is due primarily to urea accumulation in the blood (which reduces RBC formation in the bone marrow), and the reduced production of erythropoietin by the kidneys, which stimulates RBC production in the marrow. Finally, because of aberrant bone-mineral metabolism in ESRD, phosphates accumulate in the blood, and must be removed using phosphate binder drugs and three (typically) sessions of hemodialysis per week.
Anemia management drugs for ESRD include erythropoietin stimulating agents (ESAs) and intravenous (IV) iron supplementation. The per-patient-per-year (PPPY) costs for ESAs and IV iron for anemia management can easily exceed $10,000. Straightforward multiplication of 500,000 ESRD patients per year times $10,000 PPPY equates to $5b - so ESRD anemia management drugs alone are a $5b/year enterprise. It warrants noting that these costs are rising because of the ever-increasing prevalence of ESRD. Altogether, ESRD patient costs amount to more than $30b per year - which is mostly reimbursed by the Centers for Medicare and Medicaid Services (CMS).
Phosphate binder drugs used for ESRD are commonly much less expensive than ESAs. The novel ferric citrate binder (Zerenex) manufactured by Keryx Biopharmaceuticals (NASDAQ:KERX) [target FDA approval June 7, 2014], uniquely removes phosphates while providing a source of iron supplementation, thereby improving RBC production and minimizing iron-deficiency anemia. This results in lower usage of ESAs and IV iron required for RBC production and iron supplementation.
Recently, a cost reduction study published in the International Journal of Nephrology and Renovascular Disease using best estimates of CMS-reported doses, standardized Red Book drug prices, and Monte Carlo uncertainty analysis indicated that if ferric citrate usage nominally reduced ESA utilization by 20% and IV iron usage by 40%, then total annual cost would be reduced by 21.2% to 4.038 (2.868-4.914) $billion. Thus, a nominal annual cost reduction of $1b could potentially be realized when using ferric citrate as a phosphate binder for hemodialysis patients with ESRD.
The most recently completed multicenter Phase III trial of ferric citrate (at present, results unpublished) has also provided promising results according to Keryx. If ferric citrate is approved by FDA, it will take several years to perform post-marketing Phase IV studies before a complete picture emerges on cost reduction of anemia management drugs, and several years to develop a history of CMS reimbursement in order to understand the full impact of ferric citrate on ESRD and associated health care costs.
Disclosure: The author is long KERX. The author wrote this article themselves, and it expresses their own opinions. The author is not receiving compensation for it. The author has no business relationship with any company whose stock is mentioned in this article.