Rituximab improves chances for kidney transplant

BOSTON (Reuters) - Genentech's cancer drug rituximab, combined with infusions of antibodies, greatly reduces the risk that a transplanted kidney will be rejected and vastly improves the chances of patients finding a donor, researchers reported on Wednesday.

About a third of the 74,000 people waiting for a kidney in the United States have poor odds of receiving one because blood transfusions, pregnancy or a previous kidney transplant have made them too sensitive to foreign tissue. This makes their bodies likely to reject an organ from all but the closest-matching donors.

Without the treatment, the waiting time for a kidney from a deceased donor among this subgroup of highly sensitive patients averaged 12 years. With the therapy, it took only five months for an acceptable organ to become available.

A team led by Dr. Stanley Jordan of Cedars-Sinai Medical Center in Los Angeles found that they could desensitize their patients with immune globulin and rituximab, sold under the brand name Rituxan.

Immune globulin is a mix of antibodies taken from blood and Rituxan is a so-called monoclonal antibody -- an engineered immune system protein that depletes the number of immune system cells called B cells.

"These were people who were very difficult to match. They had been on the waiting list for many years," Jordan said in a telephone interview. "Less than 5 to 10 percent would have gotten a kidney."

Genentech paid for the study of 20 volunteers. The drug, marketed in the European Union as MabThera by Roche, is also used to treat rheumatoid arthritis, leukemia and lymphoma.

"We've treated more than 100 patients with the protocol and we have an 80 percent transplant rate," said Jordan, who reported that the one-year success rate for the transplanted kidneys continues to be about 94 percent. "It's holding up very well with larger numbers."

People who cannot get a transplant remain on dialysis and are more likely to die.

"Thus, early transplantation would result in considerable cost savings, reduced morbidity and mortality, and improved quality of life," Jordan's team wrote in their study in Thursday's New England Journal of Medicine.

"Their approach may represent a breakthrough in the care of sensitized patients awaiting transplantation and may have the potential to help thousands of patients who are languishing on waiting lists around the world," said Dr. Ron Shapiro of the University of Pittsburgh.

But, in a commentary in the Journal, he cautioned that the patients did have higher levels of rejection that needed to be managed.

"Attempting transplantation under such circumstances is not for the faint of heart. Caring for these highly sensitized patients requires careful, long-term monitoring after transplantation," he wrote.

Jordan said heart and lung transplant candidates sometimes have sensitization issues. "Heart patients seem to be the next-biggest category that would benefit from this therapy," he said.