Genzyme Corp. has announced the results of two new studies comparing a powder form of Renvela (sevelamer carbonate) to Renagel tablets (sevelamer hydrochloride), including one trial in which patients received the powder form three times per day, and one in which it was administered once per day.

Genzyme is developing Renvela in powder form to provide an additional option for patients with chronic kidney disease in managing their phosphate levels. A New Drug Application for Renvela tablets is already on file with the FDA, and previous studies have shown that the tablet formulation provides equivalent phosphate control to Renagel in patients on dialysis and significant phosphorus control in patients with chronic kidney disease who are not on dialysis. Today's results are the first from trials comparing the efficacy of the powder form of Renvela to Renagel tablets.

In the first powder trial, patients treated with the powder form of Renvela three times per day experienced equivalent phosphorus control to patients treated with Renagel tablets three times per day. As a result, this trial successfully met its primary endpoint.

In the second trial, patients dosed with the powder form of Renvela once per day and those treated with Renagel tablets three times per day achieved statistically significant reductions in serum phosphorus, with both groups reaching target levels for phosphorus control outlined in the K/DOQI treatment guidelines. Phosphorus levels in the Renagel arm (4.6 mg/dL) were lower than those in the Renvela arm (5.3 mg/dL), and this trial did not achieve its primary endpoint of demonstrating non-inferiority of Renvela powder dosed once per day to Renagel tablets dosed three times per day.

In both trials, the safety profile of Renvela was consistent with the previous clinical experience of patients on dialysis using Renagel. With today's results, Genzyme has concluded that the powder formulation of Renvela dosed three times per day may represent a promising alternative for patients with chronic kidney disease. The company will continue to move ahead aggressively with clinical and regulatory plans for the powder formulation dosed three times per day, and these data will form part of an NDA submission in the first half of 2008.

"We are very pleased with the progress we have made to date in our multi-faceted development program for Renvela, including filing an NDA for patients on dialysis, completing a successful trial in the pre-dialysis population, and demonstrating the effectiveness of the powder formulation dosed three times per day," said John P Butler, president, Genzyme renal.

"Results of the once-per-day trial were greatly influenced by the strong phosphorus reduction seen in the Renagel arm, which was superior to that seen in all but one previously conducted clinical trials. While today's results will not currently support a regulatory filing for once-per-day dosing, they are clinically meaningful and give us confidence that this approach can be effective. We will continue to work with regulatory authorities to design an appropriate clinical plan to gain approval for this dosing regimen."