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Drug Helps Patients at High Risk for Leukemia
Gentle Therapy Gives Some Elderly More Options and Hope
January 2005 - A drug gentle enough for patients in their 70s or 80s is showing promise for the treatment of myelodysplastic syndrome (MDS), a pre-leukemic disorder that can progress to acute myelogenous leukemia (AML), according to study results presented in December at the annual meeting of the American Society of Hematology.
The drug R115777, or tipifarnib (Zarnestra®), produced results ranging from complete responses to improvements in blood counts in about one-third of 82 patients, says the studys lead investigator, Razelle Kurzrock, M.D., director of the Phase I Program in the Division of Cancer Medicine at M. D. Anderson. Study participants were treated at seven hospitals in the United States, Canada and Europe.
Therapy gives new treatment option to MDS patients
The treatment outcome, which includes well-tolerated side effects, gives the mostly elderly patients who develop MDS a much-needed alternative, Kurzrock says. It is one more drug that can be tried to help improve blood counts and prevent leukemia development in these patients, she says.
When the study began, there was no approved therapy to treat MDS, but recently, the U.S. Food and Drug Administration (FDA) approved use of azacytidine (VidazaTM), a chemotherapy drug administered by injection.
Tipifarnib helps about as many patients as azacytidine, but for diseases like MDS you need more than one drug because the syndrome is made up of many subtypes and therefore only a limited number of patients will respond to any one drug, Kurzrock says. Therefore, if one drug doesnt help, then the other might; or they could potentially be used together.
Drug can help patients with mutated and normal genes
Tipifarnib belongs to a group of drugs known as farnesyl transferase inhibitors, which block enzymes needed for the activation of cancer-promoting proteins.
The drug was initially believed to act primarily on the ras gene, which regulates the growth of cells. Normal cells need a good ras gene in order to grow and make new DNA.
While the ras gene is mutated in about 25% of MDS patients, recent studies, including this one, demonstrate that patients whose ras gene is normal can benefit, Kurzrock says. It has become apparent that tipifarnib regulates other important cancer genes, although we dont know which ones they are.
Cord Blood from Two Donors Okay for Leukemia
NEW YORK (Reuters Health) - Feb 4, 2005 - Transplanting umbilical cord blood from two separate donors appears to be a safe and effective treatment for leukemia, new research suggests. The findings suggest that umbilical cord blood transplants could be made available to thousands more adolescent and adult patients, Dr. Juliet N. Barker of the University of Minnesota in Minneapolis and colleagues write in the medical journal Blood.
Umbilical cord blood transplants have advantages over bone marrow transplantation--including rapid access and little risk of graft-versus-host disease (GVHD), a serious condition that occurs when blood cells present in the transplant actually attack the recipient. However, umbilical cord blood donations to adults have been sharply limited by the small size of a single unit, Barker and her team note.
The researchers conducted the current study to determine if this limitation could be overcome by giving adults two units of partially matched umbilical cord blood from separate donors. Twenty-three patients received the transplants for severe forms of leukemia.
While two of the patients died of infection shortly after transplantation, the umbilical cord blood transplant successfully took root or "engrafted" in all of the other patients. Engraftment is the main goal for any type of transplant.
At one year, 72 percent of the patients who had received the transplant during remission were still alive. Moreover, the rate of GVHD was no greater than that seen with single-unit umbilical cord blood transplants.
The authors conclude: "Transplantation of two partially...matched umbilical cord blood units is safe, and may overcome (the barriers that limit) the use of umbilical cord blood in many adults and adolescents."
SOURCE: Blood, January 25, 2005.