The phosphate-binding affinity of Fosrenol (lanthanum carbonate) was more than 200 times higher compared to sevelamer HCl (marketed by Genzyme as Renagel) at pH 3, which simulates the acidic environment of the stomach.
When assessed at pH 5 to 7, the affinity of Fosrenol was four-fold higher compared to sevelamer HCl. In addition, the presence of bile acids did not affect the stability of the Fosrenol/phosphate complex, whereas bile acids led to a more than 20-fold reduction in phosphate-binding affinity of sevelamer HCl with the consequent release of its phosphate.
In addition to the binding affinity data, another study found that Fosrenol continued to demonstrate sustained efficacy, tolerability and safety in patients treated for up to five years. As patients continued on therapy, the number of adverse events decreased. In fact, by the fifth year, no patients reported treatment-related adverse events. In addition, Fosrenol-treated patients maintained serum phosphorus reductions for up to five years.
Without effective treatment, hyperphosphatemia (high levels of phosphorus in the blood) can lead to renal osteodystrophy in end stage renal disease (ESRD) patients, and an increased risk of bone pain, skeletal deformities and fractures. Accumulating evidence also shows that hyperphosphatemia may contribute to cardiovascular disease, which accounts for almost half of all deaths among dialysis patients.