In a preliminary clinical trial, most patients with acute leukemia who received a cord-blood stem cell transplant through an injection directly into the iliac crest of the pelvic bone, experienced complete hematologic recovery - a restoration of normal white blood cell and platelet counts, produced by the donor stem cells - within an average of 36 days.

Previous clinical trials testing cord-blood stem cells delivered intravenously have shown that intravenous transplants fail in about 20 percent of patients. The current trial, published online August 9 in Lancet Oncology, tested whether cord-blood transplantation (which provides a lower number of stem cells than bone-marrow transplantation) would be safe and more successful if delivered directly into the bone marrow, where blood cells form.

The investigators, led by Dr. Francesco Frassoni of San Martino Hospital in Genoa, Italy, enrolled 32 patients who were eligible for bone-marrow transplantation but could not find an HLA-matched donor. After conditioning chemotherapy with or without radiation, all patients received a cord-blood transplant into the left iliac crest, the right iliac crest, or both sites. All patients received immunosuppressive drugs to prevent graft-versus-host disease (GvHD).

Four patients died within 12 days of the transplant, and one patient died 30 days after the procedure, before platelet restoration. The remaining 27 patients regained normal blood counts, regardless of whether they received the injection in one or both sites, and 45 percent survived at least 1 year after transplantation. Other studies using intravenous transplantation have shown platelet recovery rates of only 40 percent to 70 percent at 100 days after transplantation.

None of the participants developed high-grade acute GvHD. Other studies have shown the incidence of GvHD with intravenous cord-blood transplant to be between 35 percent and 45 percent.

The authors caution that their findings will need to be confirmed in larger studies that follow patients for a longer period of time.