Researchers have determined the new anti-rejection drug Everolimus is easier on the kidneys following a liver transplant, compared to Tacrolimus, the drug that's been routinely prescribed to liver recipients. Everolimus also helps liver recipients avoid weight gain. Both factors are important factors in a patient's post-transplant health and can lead to positive outcomes.

The results of the study, which were presented earlier this month at the American Transplant Congress in Chicago, found that patients who received Everolimus gained less weight than those taking Tacrolimus and were able to keep it off for two years after starting the drug.

"Everolimus did have less impact on kidney function, and the Food and Drug Administration approved the drug based on that finding for use in liver transplant patients," said Dr. Michael M. Charlton, a researcher and clinician from the Intermountain Medical Center Center Transplant Program and the study's lead author. Everolimus was first approved for use in liver transplant recipients by the FDA in 2013.

Weight gain after liver transplant is an important consideration as it can seriously increase the probability that patients will develop post-implant cardiovascular disease, kidney failure and metabolic syndrome — a condition that can cause diabetes, obesity, hypertension and abnormal cholesterol and fat levels, all of which can lead to stroke or heart disease.

Initial research showed that Everolimus prevented weight gain in fruit flies and other animals, so the researchers wanted to see if the same was true in humans, as well. During a randomized test, 719 patients between 25 and 35 days after liver transplant were split into three study arms.

The first group of 245 patients received Everolimus and a reduced dose of Tacrolimus; the second group of 243 received the usual dose of Tacrolimus and served as the control group; the final group of 231 patients were prescribed only Everolimus to suppress their immune systems.

"We found that the two Everolimus groups in this study gained around 10 pounds less than patients in the tacrolimus arm," Charlton said. "It used to be that rejection was a big deal and that was the most common cause of liver rejection or death. Now, the most common cause of death following liver transplantation is related to cardiovascular events and cancers, with kidney function increasingly important as well. Cardiovascular disease, cancers and renal disease are driven in part by weight."

The randomized, multicenter trial was conducted at the Intermountain Medical Center Transplant Program in Salt Lake City. It involved researchers at Northwestern University, Novartis Pharmaceuticals and the Mayo Clinic. The study appears in the American Journal of Transplantation.

"Since nearly everyone who receives a liver transplant gains weight after the surgery, this could be an easy way to avoid or limit the need for a transplant," Charlton said.