      
    |
Advances in Research Reported at Meeting of Hematologists The annual meeting of the American Society of Hematology (ASH), which was held December 3-7, 1999 in New Orleans, was an exciting forum where researchers presented the latest results of their work. The report that generated the most excitement was Brian Druker’s study of STI 571 (see story, page 6)—a drug that’s been remarkably effective so far in treating chronic myelogenous leukemia. What follows is a capsule summary of several other presentations of interest to transplant patients and survivors. Peripheral Blood Stem Cells Favored over Bone Marrow for Allogeneic Transplants Persons undergoing an allogeneic transplant have been traditionally infused with donor bone marrow. But a large, multi-center study involving 168 patients with leukemia, lymphoma, Hodgkin disease or myelodysplasia found that, on average, patients fare better when infused with stem cells collected from the donor’s blood stream than with donor bone marrow. The study, conducted by transplant teams at the Fred Hutchinson Cancer Research Center, City of Hope Medical Center, Stanford University and the University of Washington, reported faster recovery of white blood cell and platelet counts, and a lower risk of relapse and death among patients transplanted with peripheral blood stem cells. The lower rate of relapse and death was seen primarily in patients with diseases that were difficult to treat successfully with a transplant. More patients infused with stem cells, however, developed acute and chronic graft-versus-host disease (GVHD) than those transplanted with bone marrow.
A similar study, published in the journal Bone Marrow Transplantation (December 1999) by Canadian researchers, compared the outcome of stem cell versus bone marrow transplants for 87 patients treated for myelodysplasia or acute myelogenous leukemia in first complete remission. Like the previous study, investigators found that patients transplanted with stem cells recovered white blood cell and platelet counts more quickly than those infused with bone marrow. However, the study also found that the incidence of chronic GVHD was markedly higher (almost double) in the group transplanted with blood stem cells, and a greater proportion of blood stem cell transplant survivors reported quality of life problems four years after transplant. Retrospective Study Suggests Autologous Transplant Improves Survival Odds for Persons with CLL Although autologous transplants are being used increasingly to treat persons with high-risk chronic lymphocytic leukemia (CLL), the impact of autologous stem cell transplantation on long-term survival has not been clear. To gain some insight into this question, an international team of researchers reviewed records of 107 high-risk CLL patients who underwent an autologous transplant since 1990. When compared with patients who received conventional therapy, survival of transplanted patients was significantly better. This was not a randomized study, however, so differences between groups may be due to “selection bias,” i.e. offering a transplant only to patients likely to withstand the rigors of the procedure. Unrelated Umbilical Cord Blood Has Benefits over Bone Marrow for Some Transplant Patients Umbilical cord blood has been successfully used instead of bone marrow or stem cells in allogeneic transplants. Researchers at the University of Minnesota compared 68 patients transplanted with bone marrow from an unrelated donor to 68 other patients who were transplanted with umbilical cord blood from an unrelated donor. Patients in each group were matched according to age, disease and how well the donor’s marrow or cord blood type matched the patient’s. Sixty-one percent of the patients had high-risk leukemia, and 81 percent had mis-matched donors. Patients transplanted with cord blood experienced significantly less acute GVHD than those transplanted with bone marrow. Although it took the cord blood group longer to recover normal white blood cell counts, their survival rate one year after transplant was superior to the bone marrow group. The majority of patients in this study were pediatric patients. Less Toxic Preparative Regimen Recommended for Myeloma Transplant Patients Prior to an autologous transplant, most myeloma patients undergo a preparative regimen consisting of high-dose melphalan and total body irradiation (TBI). Researchers at the University Hospital in Nantes, France, compared this regimen to one consisting of a higher dose of melphalan but no total body irradiation. After evaluating results in 231 patients, the team concluded that the higher dose of melphalan without total body irradiation should be the standard preparative regimen for myeloma patients undergoing autologous transplant. Patients on this regimen recovered white blood cell and platelet counts more quickly than those on the TBI regimen, required fewer blood and platelet transfusions and antibiotics, had less difficulty with mouth sores, and had survival rates similar to those on the regimen with TBI. Four patients on the regimen with TBI died of treatment-related causes compared to none on the higher dose melphalan regimen. Double Transplant Improves Survival Rates for Some Myeloma Patients A team of French investigators tested whether a double transplant (also called tandem transplant) was superior to a single autologous transplant for persons with multiple myeloma. The study involved 402 patients between 1994 and 1997. Although it is too early to report final results, a mid-study analysis found that survival rates three years after diagnosis did not differ significantly between the two groups. However, for patients with a beta-2 microglobuline <3mg/l at the time of diagnosis, double transplantation did appear to improve overall survival. Removing Tumor Cells from Stem Cell Sample May Improve Outcome for Breast Cancer Patients Stem cells harvested from patients with breast cancer prior to an autologous transplant often contain cancer cells. Various methods are being explored to remove these tumor cells, since they may cause relapse. One method involves removing a small amount of bone marrow from the patient, growing it in the laboratory under conditions that are not favorable to tumor cells, and reinfusing it back into the patient following high dose chemotherapy. This technique was used on 34 patients at the Loyola University Medical Center between 1986 and 1988. Of the 12 patients transplanted for Stage II/IIIa disease, 92 percent remained progression free (i.e., the disease did not progress to a more advanced stage) a median of 27 months after transplant. The median progression-free survival for patients with Stage IV disease was 15.5 months. The results achieved with these patients were superior to those seen in other breast cancer patients transplanted with peripheral blood stem cells at the same center. Although research is still at an early stage, this study suggests that removing tumor cells from the stem cells or bone marrow reinfused into breast cancer patients may prolong survival. Patients With Aggressive, High-Risk non-Hodgkin Lymphoma Benefit from Early High Dose Chemotherapy and an Autologous Transplant Researchers from the Henri Mondor Hospital in Creteil, France, reported that high-risk non-Hodgkin lymphoma patients treated with high dose chemo-therapy (cyclophosphamide, carmustine and VP16) and an autologous stem cell transplant following induction chemotherapy fared better than those treated with lower dose consolidation chemotherapy (ifosfamide, etoposide, asparaginase, and cytarabine). Eight years after treatment, 55 percent of 125 patients in the transplant group were disease-free, compared with 39 percent of the 111 patients in the lower-dose consolidation chemotherapy group. The research team recommended that patients at high risk of relapse who achieve a complete remission after induction chemotherapy should be offered high-dose chemotherapy and an autologous transplant to maximize long-term survival. Encouraging Results in Mantle Cell Lymphoma Treatment Mantle cell lymphoma has traditionally been a difficult form of lymphoma to treat. Researchers at M.D. Anderson reported encouraging results after treating patients with a novel pre-transplant chemotherapy series, followed by high dose chemotherapy and an autologous or allogeneic stem cell transplant. Of the 35 patients who proceeded to transplant, 31 were alive and disease-free a median of 34 months after transplant, which is a better outcome than expected from traditional treatment. Patients ranged in age from 41 to 59 years. To view abstracts of all the presentations made at the ASH Annual Meeting, visit their website at www.hematology.org. |
||
|
|||
