CAMBRIDGE, Mass. (AP) -- Genzyme Corp. said Wednesday it is canceling development of a successor to its kidney treatment Renvela, as the new drug did not work much better than Renvela.

Genzyme said the newer product, called an advanced phosphate binder, met a main trial goal by being more effective than a placebo at lowering serum phosphorous levels in patients with chronic kidney disease. But the company was hoping the drug would outperform Renvela, which was launched in early 2008.

Serum phosphorus is a chemical that helps people take energy from food. When the kidneys cannot properly filter serum phosphorous, it builds up in the body and can cause calcification of tissues. Before Renvela was approved, Genzyme marketed an older drug, Renagel, for the same purpose.

The trial included 349 patients on dialysis. After a screening and a two-week break from their current treatment, they were given a high, medium or low dose of the advanced phosphate binder or Renvela, or a placebo, for three weeks.