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Investigational Transplant Drug Preserves Kidneys While Avoiding Toxic Side Effects Common to Immunosuppressant Medications

February 21, 2005

Yerkes-based nonhuman primate study expedited the research process for this medication, now in phase II human clinical trials

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Lisa Newbern, 404-727-7709,; Holly Korschun, 404-727-3990,

ATLANTA – Physician-researchers at Emory University in Atlanta have shown an investigational medication, known as LEA29Y, is effective in preserving transplanted kidney function while at the same time avoiding the toxic side effects that are common in the currently used long-term, immunosuppressive transplant medications. The pre-clinical research conducted with nonhuman primates at the Yerkes National Primate Research center was an important step in establishing ongoing human clinical trials to develop an effective alternative to current anti-rejection therapies. Findings from the nonhuman primate study appear in the March issue of the American Journal of Transplantation.

More than 23,000 organ transplants are performed each year in the United States. While current immunosuppressant medications have reduced the incidence of early organ failure following transplants, measures to prevent late failure and to halt other diseases that result from toxic side effects of current treatments have been limited.

Cyclosporine, the current standard of care following organ transplantation, prevents initial organ rejection by effectively blocking certain immune system pathways that are activated when the body detects foreign cells. At the same time, though, cyclosporine indiscriminately targets and blocks other cellular signal pathways, causing serious side effects such as high blood pressure and cholesterol, which may lead to cardiovascular disease, and high kidney toxicity that ultimately leads to long-term renal failure. In addition, long-term cyclosporine use damages the body’s immune system and prevents it from fighting off other infections following transplant.

“For the past 20 years, transplant patients have been treated with cyclosporine-like medications that effectively suppressed the immune system to prevent the body from rejecting the new organ,” said Christian Larsen, MD, DPhil, director of the Emory Transplant Center. “The problem is, the medication shuts down the immune system, so patients die from other complications. We want to develop a medication as effective as cyclosporine in preventing initial rejection, while at the same time preserving the kidney and providing better patient outcomes.”

Dr. Larsen and Thomas Pearson, MD, DPhil, with colleagues at Bristol Myers-Squibb Pharmaceutical Research Institute, developed LEA29Y to selectively block the second of two cellular signals (co-stimulatory signals) the body needs to trigger an immune response. Blocking this co-stimulatory signal prevents organ rejection while allowing the body to continue fighting other infections.

Following in vitro studies, during which the researchers observed LEA29Y was 10 times more effective than cyclosporine in blocking the co-stimulatory immune signal, Drs. Larsen and Pearson tested the drug in nonhuman primates and found that it significantly prolonged survival of transplanted kidneys. The research team currently is studying the treatment in a phase II clinical study involving human kidney transplant patients.

“The studies with nonhuman primates were critical because we knew the co-stimulatory blocker was effective, but we needed to study it in a living organism,” said Dr. Larsen. “The nonhuman primate study allowed us to take a bold step toward studying this medication in humans to determine if it is a better choice than the current standard of care. The nonhuman primate studies enabled us to expedite the research process by four or five years.”

Drs. Larsen and Pearson will present data from the human clinical trial at the annual American Transplant Congress, May 20-25, in Seattle.

The Emory Transplant Center is one of the most advanced and comprehensive transplant centers in the Southeast. The center brings together Emory University's transplantation programs in heart, lung, liver, kidney, pancreas and islet. The center is committed to providing and improving care and access to those in need of organ transplantation, through full-service patient care and support services, as well as groundbreaking research to further the field of transplantation.

The Yerkes National Primate Research Center of Emory University is one of eight National Primate Research Centers funded by the National Institutes of Health. The Yerkes Research Center is a recognized leader for its biomedical and behavioral studies with nonhuman primates, which provide a critical link between research with small laboratory animals and the clinical trials performed in humans. Yerkes researchers are on the forefront of developing vaccines for AIDS and malaria, and treatments for cocaine addiction and Parkinson’s disease. Yerkes researchers also are leading programs to better understand the aging process, pioneer organ transplant procedures and provide safer drugs to organ transplant recipients, determine the behavioral effects of hormone replacement therapy, prevent early onset vision disorders and shed light on human behavioral evolution.

This research was supported by the National Institutes of Health, the National Science Foundation, the Carlos and Marguerite Mason Trust, the Livingston Foundation and Bristol-Myers Squibb.

The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Winship Cancer Institute of Emory University; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, and Emory University Orthopaedics & Spine Hospital. The Woodruff Health Sciences Center has a $2.5 billion budget, 17,600 employees, 2,500 full-time and 1,500 affiliated faculty, 4,700 students and trainees, and a $5.7 billion economic impact on metro Atlanta.

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