A new study released by Wyeth about its anti-organ transplant rejection drug, Rapamune, says that the drug may increase the risk of death when used after a liver transplant. The U.S. Food & Drug Administration (FDA) has issued a warning to doctors about the study's results.

What is Rapamune?

Rapamune is an anti-organ transplant rejection drug manufactured by Wyeth Laboratories which has been approved by the FDA for for the management of hemolytic-uremic syndrome (HUS) following kidney transplantation. However, doctors routinely prescribe it off-label to those who have undergone liver transplants – although it already contains a “black box” warning which advises doctors not to use it after liver transplants.

Details of the Wyeth study

Wyeth's study revealed that patients who use Rapamune (sirolimus), an immunosuppressant used to prevent the body from rejecting an organ after transplant, had a greater chance of liver rejection and a possible increased risk of death among liver transplant patients who were using a calcineurin inhibitor (CNI)-based immunosuppressive treatment and then switched to Rapamune.

The study also found that:

• the chance for a transplant patient's body to reject the new liver was “significantly higher” for stable liver transplant patients who switched from a CNI treatment to Rapamune than those who continued to use a CNI treatment
• more liver transplant patients discontinued using Rapamune due to adverse events than those who used a CNI treatment
• peripheral edema, stomatitis, rash and mouth ulcerations were the most frequent side effects of Rapamune which led to patients discontinuing its use

The study's results prompted the FDA to send a warning letter to doctors on June 11, 2009 about the new findings, but the Administration says that it will investigate further to determine whether other actions are necessary. Unfortunately, liver patients aren't the only ones at risk.

Risk of diabetes increased in kidney patients

A study published in the Journal of the American Society of Nephrology in July of 2008 found that kidney transplant patients who used Rapamune as directed had a 36% higher chance of contracting diabetes.

If you've been injured by Rapamune, consult with an experienced products liability attorney to discuss your situation and evaluate your options.