Astellas Pharma announced that its U.S. subsidiary has received an approvable letter from the FDA in response to the company's supplemental new drug application (sNDA) for Prograf plus mycophenolate mofetil (MMF) as an adjunct therapy for the prophylaxis of organ rejection in kidney transplant patients.

Prograf (tacrolimus) is currently approved for the prevention of organ rejection in kidney, liver and heart transplant patients.

In the letter, the FDA raised concerns that the combination of Prograf and MMF 2 grams/day may lead to an increase in infection-related mortality due to over-immunosuppression, based on the agency's review of study data included in the sNDA.

The study, which was published in the March issue of the American Journal of Transplantation, was a three-arm, multicenter, Phase III, randomized, open-label study involving 638 kidney transplant patients. The one-year survival rate in the three study arms was 95.7 percent in the Prograf plus MMF group, 97.6 percent in the cyclosporine plus MMF group and 98.6 percent in the extended-release tacrolimus group.

Astellas said it plans to work with the FDA to resolve the differences in the interpretation of the study data in pursuit of approval of the sNDA.

Earlier this year the company received FDA approvable letters for its application for extended-release tacrolimus in treating kidney and liver transplant patients, and a not approvable letter in response to the heart transplant indication.