Genzyme General (Genzyme Corporation) / GelTex Pharmaceuticals Inc.

Hyperphosphatemia in End-Stage Renal Disease (Dialysis)

120K US cases/yr

Disease Overview

Hyperphosphatemia is a near-universal complication of end-stage renal disease in patients on dialysis: failing kidneys cannot excrete dietary phosphate, driving secondary hyperparathyroidism, vascular calcification, and excess cardiovascular mortality. Phosphate binders taken with meals are the cornerstone of management, alongside dietary restriction and dialysis adequacy.

Competitive Landscape

In 2000, the US phosphate binder market was dominated by calcium-based binders (calcium acetate / PhosLo, calcium carbonate / Tums) and aluminum hydroxide. The clinical concern was that calcium binders worsened vascular calcification, an emerging driver of cardiovascular mortality in dialysis patients. GelTex's Renagel (sevelamer hydrochloride) was the first non-calcium, non-aluminum binder — a non-absorbed polymer that bound phosphate in the GI tract — launched in 1998 and growing fast (1999 sales $19.5M, 2000 guidance ~$45M, with management projecting $500M in five years and $1B within a decade). Genzyme already co-promoted Renagel and saw the polymer platform as a natural fit alongside its rare-disease and renal franchises. The all-stock $1B deal also brought WelChol (colesevelam), a bile-acid-sequestrant polymer for hypercholesterolemia, plus a 12-program polymer pipeline. Competitive followers eventually included Shire's Fosrenol (lanthanum, FDA 2004) and Keryx's Auryxia (ferric citrate, FDA 2014); Sanofi's Renvela (sevelamer carbonate, FDA 2007) was a Genzyme-developed reformulation. Renagel/Renvela peaked above $800M in annual sales, validating the deal but undershooting the original $1B vision.