Swiss drug giant Novartis (NVS 2.00%) says the FDA has approved Zortress, its mTOR inhibitor (a protein that controls the growth of tumors and blood vessels) for the prevention of organ rejection in adult patients receiving a liver transplant.

It's the first time in over a decade an immunosuppressant has been approved in the U.S. for use following liver transplantation, according to the company.  Previously, Zortress had been approved for kidney transplantation.

The approval was based on the largest liver transplant study to date, according to Novartis, in which 719 patients started using the drug 30 days after the operation. Study results showed that Zortress plus reduced tacrolimus led to comparable efficacy and higher renal function compared to standard tacrolimus after a year. Tracrolimus is part of the standard-of-care treatment regimen for immunosuppression in liver transplantation.

European health authorities approved the use of Zortress in the fourth quarter of 2012 and Novartis says it is one of the most extensively studied immunosuppressants in solid organ transplantation, with more than 10,000 transplant recipients enrolled in Novartis-sponsored clinical trials worldwide.

It is approved in more than 90 countries to prevent organ rejection for renal and heart transplant patients under the trade name Certican.

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