Ovarian function after autologous bone marrow transplantation

PURPOSE

To determine the frequency of return of ovarian function after autologous bone marrow transplantation (ABMT), and the major factors that predict recovery.

PATIENTS AND METHODS

Records of 200 consecutive women who underwent ABMT at the University of Toronto Autologous Blood and Marrow Program (Toronto, Canada) were reviewed. Seventeen patients met the inclusion criteria, which were (1) alive at the time of evaluation, (2) disease-free at least 18 months after transplantation, (3) age younger than 50 years at transplantation, and (4) premenopausal before transplantation. Recovery of ovarian function was determined by pregnancy or regular menses, with no menopausal symptoms and an estradiol level greater than 20 pmol/L off hormonal therapy.

RESULTS

All 17 patients became menopausal immediately after ABMT. Five patients (29%) recovered ovarian function a median of 24 months post-ABMT (range, 6 to 48 months). The median age at transplantation of women with restored ovarian function was 19 years (range, 19 to 28 years) versus 30 years (range, 22 to 48 years) for those who did not regain function. Younger age at transplantation predicted ovarian recovery (P = .03) by means of a log-rank test. Only one of five women who regained ovarian function received total-body irradiation (TBI) compared with five of 12 women who did not. Univariate analysis suggested a trend for TBI to predict a sustained loss of ovarian function (P = .067). The number of regimens of induction or salvage chemotherapy that contained an alkylating agent ranged from none to five and was not predictive (P = .45).

CONCLUSION

All women became menopausal after ABMT but 29% recovered ovarian function. Younger age at transplantation predicted return of ovarian function, whereas TBI may have had a negative effect.

A multicenter study of platelet recovery and utilization in patients after myeloablative therapy and hematopoietic stem cell transplantation

An observational study was conducted at 18 transplant centers in the United States and Canada to characterize the platelet recovery of patients receiving myeloablative therapy and stem cell transplantation and to determine the clinical variables influencing recovery, determine platelet utilization and cost, and incidence of hemorrhagic events. The study included 789 evaluable patients transplanted in 1995. Clinical, laboratory, and outcome data were obtained from the medical records. Variables associated with accelerated recovery in multivariate models included (1) higher CD34 count; (2) higher platelet count at the start of myeloablative therapy; (3) graft from an HLA-identical sibling donor; and (4) prior stem cell transplant. Variables associated with delayed recovery were (1) prior radiation therapy; (2) posttransplant fever; (3) hepatic veno-occlusive disease; and (4) use of posttransplant growth factors. Disease type also influenced recovery. Recipients of peripheral blood stem cells (PBSC) had faster recovery and fewer platelet transfusion days than recipients of bone marrow (BM). The estimated average 60-day platelet transfusion cost per patient was $4,000 for autologous PBSC and $11,000 for allogeneic BM transplants. It was found that 11% of all patients had a significant hemorrhagic event during the first 60 days posttransplant, contributing to death in 2% of patients. In conclusion, clinical variables influencing platelet recovery should be considered in the design and interpretation of clinical strategies to accelerate recovery. Enhancing platelet recovery is not likely to have a significant impact on 60-day mortality but could significantly decrease health care costs and potentially improve patient quality of life.

High level engraftment of NOD/SCID mice by primitive normal and leukemic hematopoietic cells from patients with chronic myeloid leukemia in chronic phase

We have previously shown that intravenously injected peripheral blood (PB) or bone marrow (BM) cells from newly diagnosed chronic myeloid leukemia (CML) patients can engraft the BM of sublethally irradiated severe combined immunodeficient (SCID) mice. We now report engraftment results for chronic phase CML cells in nonobese diabetic (NOD)/SCID recipients which show the superiority of this latter model. Transplantation of NOD/SCID mice with 7 to 10 x 10(7) patient PB or BM cells resulted in the continuing presence of human cells in the BM of the mice for up to 7 months, and primitive human CD34+ cells, including those detectable as colony-forming cells (CFC), as long-term culture-initiating cells, or by their coexpression of Thy-1, were found in a higher proportion of the NOD/SCID recipients analyzed, and at higher levels than were seen previously in SCID recipients. The human CFC and total human cells present in the BM of the NOD/SCID mice transplanted with CML cells also contained higher proportions of leukemic cells than were obtained in the SCID model, and NOD/SCID mice could be repopulated with transplants of enriched CD34+ cells from patients with CML. These results suggest that the NOD/SCID mouse may allow greater engraftment and amplification of both normal and leukemic (Ph+) cells sufficient for the quantitation and characterization of the normal and leukemic stem cells present in patients with CML. In addition, this model should make practical the investigation of mechanisms underlying progression of the disease and the development of more effective in vivo therapies.

New clonal karyotypic abnormalities acquired following autologous bone marrow transplantation for acute myeloid leukemia do not appear to confer an adverse prognosis

We undertook a retrospective review of all 76 patients with AML transplanted between August 1986 and March 1995 at our center. All patients received melphalan (140-160 mg/m2), etoposide (60 mg/kg) and total body irradiation. All patients had bone marrow cytogenetic analysis at regular intervals following ABMT. The primary study end point was the development of the new cytogenetic abnormalities. Secondary end points were the development of myelodysplasia (MDS) or AML. Sixty-two of 77 patients were alive at least 6 months post transplant. Cytogenetic abnormalities developed in 7/62 patients (11%) following ABMT. No patients demonstrated MDS or AML. At a median of 30 months after development of the cytogenetic abnormality, only one patient developed features suggestive but not diagnostic of MDS. All seven patients remain alive and leukemia-free up to 70 months after detection of the abnormal clone. There was no increased incidence of cytogenetic abnormalities developing in patients receiving a purged autograft. New cytogenetic abnormalities are frequent following ABMT for AML but do not appear to predict development of myelodysplasia or acute myeloid leukemia. These abnormalities may relate to use of total body radiation as part of the high-dose therapy.

Expression of Factor IX cDNA Introduced into Human Marrow Stromal Cells by Electroporation

Management of hemophilia B with gene therapy is an attractive and potentially feasible goal since stringent regulation of the recombinant protein is not required and low circulating levels may be sufficient to prevent symptoms. We are investigating the potential of gene transfer by electroporation for a role in human gene therapy. In this study, we used electroporation to physically co-transfer human factor IX cDNA under the influence of the potent human CMV-IE promoter and a second plasmid containing a neomycin resistance gene into human bone marrow stromal cells. Following electroporation, stromal cells were selected for neomycin resistance as co-transfection of both plasmids into the cells was expected from the results of previous studies. Analysis of genomic DNA from transfected stromal cells showed stable integration of factor IX cDNA at several sites in the genome. Following electroporation, the stromal cells were shown to secrete factor IX for three weeks in culture at a maximum concentration of 17ng/10(6) cells/day. As is the case with normal, functionally active, endogenous factor IX, the glutamic acid residues in the Gla domain of the factor IX protein were found to be post-translationally modified. Our results demonstrate the feasibility of gene transfer by electroporation and the successful post-translational modification and secretion of the human factor IX protein by stromal cells. This study provides evidence of the feasibility of electroporation and the use of stromal cells for the potential correction of hemophilia B in human gene therapy.

Granulocyte-macrophage colony-stimulating factor-associated histiocytosis and capillary-leak syndrome following autologous bone marrow transplantation: two case reports and a review of the literature

Bone marrow (BM) histiocystosis in association with the administration of granulocyte-macrophage colony-stimulating factor (GM-CSF) is a rare phenomenon with few published cases. We report two cases of BM histiocystosis in patients with Hodgkin's disease treated with GM-CSF after autologous bone marrow transplantation. Both patients also developed clinical features of capillary leak syndrome, another rare complication of GM-CSF administration. GM-CSF-induced histiocystosis should now be considered in the differential diagnosis of delayed engraftment post-autotransplant.

Human gene therapy

Human gene therapy and its application for the treatment of human genetic disorders, such as cystic fibrosis, cancer, and other diseases, are discussed. Gene therapy is a technique in which a functioning gene is inserted into a human cell to correct a genetic error or to introduce a new function to the cell. Many methods, including retroviral vectors and non-viral vectors, have been developed for both ex vivo and in vivo gene transfer into cells. Vectors need to be developed that efficiently transfer genes to target cells, and promoter systems are required that regulate gene expression according to physiologic needs of the host cell. There are several safety and ethical issues related to manipulating the human genome that need to be resolved. Current gene therapy efforts focus on gene insertion into somatic cells only. Gene therapy has potential for the effective treatment of genetic disorders, and gene transfer techniques are being used for basic research, for example, in cancer, to examine the underlying mechanism of disease. There are still many technical obstacles to be overcome before human gene therapy can become a routine procedure. The current human genome project provides the sequences of a vast number of human genes, leading to the identification, characterization, and understanding of genes that are responsible for many human diseases.

Salvage chemotherapy with mini-BEAM for relapsed or refractory non-Hodgkin's lymphoma prior to autologous bone marrow transplantation

BACKGROUND

The role of intensive chemotherapy with autologous blood and marrow transplantation (ABMT) for patients with relapsed or refractory intermediate grade non-Hodgkin's lymphoma has recently been established. However, conventional dose salvage chemotherapy is frequently used to determine chemotherapy sensitivity and reduce tumor bulk prior to intensive therapy. Different salvage regimens have been proposed but none appears significantly superior. The purpose of this study was to determine the efficacy of mini-BEAM salvage chemotherapy in patients referred for AMBT and to define prognostic factors of response.

PATIENTS AND METHODS

One hundred four patients referred for consideration of AMBT after failure of primary anthracycline-based chemotherapy received BCNU 60 mg/m2 day 1, etoposide 75 mg/m2 day 2-5, ara-C 100 mg/m2 q12 h day 2-5, melphalan 30 mg/m2 day 6 (mini-BEAM) until maximum tumor reduction. Median age was 52 (range 18-65), 57% had failed to achieve a complete response (CR) to doxorubicin-based chemotherapy at diagnosis and only 13% had a previous CR lasting > 12 months. Seventy-six received mini-BEAM as first salvage chemotherapy.

RESULTS

The overall response rate (RR) was 37% (95% confidence interval (CI) 28-46%) with 12 patients achieving CR and 25 achieving PR. The response rate among patients treated as first salvage was 43% compared to 20% for patients who had failed to respond to a previous salvage regimen. Only 15% of patients who failed to respond to mini-BEAM responded to another conventional dose salvage regimen. Thirty-eight of 104 patients ultimately demonstrated sufficient response to proceed to ABMT. Actuarial survival at four years is 22% for all 104 patients, and 36% for those who went on to AMBT. For those who were not transplanted, four-year survival was 18%. B symptoms and tumor burden at relapse were significant predictors of response to mini-BEAM in multivariate analysis, and identified a poor prognosis group of patients unlikely to be cured by the approach.

CONCLUSIONS

Mini-BEAM does not appear to be a superior salvage regimen in this high-risk group of relapsed or refractory NHL patients for whom ABMT was the ultimate treatment intention. Only one-third of patients referred for ABMT ultimately proceed to transplant; alternative treatment strategies should be developed for those with a low likelihood of cure by this approach.

A phase I study of interleukin-6 after autologous bone marrow transplantation for patients with poor prognosis Hodgkin's disease

We performed a pilot study of human recombinant IL-6 (SDZ ILs 969) in 6 patients with poor prognosis Hodgkin's disease following autologous bone marrow transplantation (ABMT) to determine its safety and tolerability. IL-6 was administered the day following bone marrow infusion by subcutaneous injection once daily at a dose of 1 micro/kg/day to 3 patients and 2.5 microg/kg/day to 3 patients and was continued for 6 weeks or until platelet engraftment (>50 x 10(9)/L independent of transfusion). No severe or life threatening toxicities were seen at either dose level. A reversible elevation in alkaline phosphatase occurred in 4 patients and all patients complained of headache, myalgias, and fever. Gastrointestinal toxicity was low, grade 3-4 mucositis occured less frequently than in similarly-treated historical controls receiving GM-CSF. Serum concentrations of other cytokines such as IL-3 and G-CSF after ABMT differed from results obtained in transplant recipients given GM-CSF. The median time to an ANC >0.5 x 10(9)/L was 25.5 days and to a platelet count of >20 x 10(9)/L independat of transfusion was 35.5 days. Engraftment was no different from controls. Five patients relapsed at a median of 5 months post-ABMT and four remain alive at a median of 12 months post-ABMT. We conclude that IL-6 administration is safe and well tolerated in patients following ABMT. Further efforts to evaluate its effect on hematopietic recovery as well as relapse following transplantation in a larger patient series are warranted.

Granulocyte-macrophage colony-stimulating factor/interleukin-3 fusion protein versus granulocyte-macrophage colony-stimulating factor after autologous bone marrow transplantation for non-Hodgkin's lymphoma: results of a randomized double-blind trial

PURPOSE

A phase III trial to compare PIXY321 with granulocyte-macrophage colony-stimulating factor (GM-CSF) following high-dose therapy and autologous bone marrow transplant (ABMT) was conducted to evaluate the time to hematopoietic recovery.

PATIENTS AND METHODS

One hundred seventy-seven patients with non-Hodgkin's lymphoma (NHL) receiving ABMT were randomized to receive either PIXY321 750 micrograms/m2/d divided into two subcutaneous (SC) doses or GM-CSF 250 micrograms/m2/d as a 2-hour intravenous (IV) infusion starting on day 0 post-ABMT for a maximum of 28 days.

RESULTS

The median time to reach an absolute neutrophil count (ANC) > or = 500/microL in the PIXY321 group was 17 days versus 19 days in the GM-CSF group (P = .07) and the median time to reach platelet transfusion independence in the PIXY321 group was 25 days versus 23 days in the GM-CSF group (P = .30). The toxicity profiles of the two agents appeared to be equivalent with the exception of more patients in the PIXY321 group with a rash (64%) compared with the GM-CSF group (48%) (P = .028). A logistic regression model identified the use of a non-total-body irradiation (TBI) regimen and/or receipt of unpurged marrow and a body-surface area greater than 2.0 m2 as predictive of faster neutrophil engraftment, and those three factors, as well as the receipt of < or = two prior chemotherapy regimens as predictive for rapid platelet engraftment.

CONCLUSION

There was a trend toward a slight improvement in neutrophil engraftment post-ABMT with the PIXY321 administered by an SC route compared with GM-CSF administered by an IV route. However, no differences could be identified between the two agents with respect to the time to platelet transfusion independence. Patient, regimen, and graft characteristics were most predictive of the engraftment tempo.

Intensive therapy and autotransplant for patients with an incomplete response to front-line therapy for lymphoma

BACKGROUND

Patients with Hodgkin's disease (HD) and intermediate or high-grade non-Hodgkin's lymphoma (NHL) who fail to achieve a complete remission (CR) with standard induction therapy have a poor prognosis with conventional-dose salvage therapy alone. We examined the role of subsequent intensive therapy and autologous bone marrow transplantation (ABMT) in patients who demonstrated a response to conventional-dose therapy.

PATIENTS AND METHODS

Sixty-six patients with either HD (n = 30) or NHL (n = 36) underwent intensive therapy with etoposide (60 mg/kg), intravenous melphalan (160-180 mg/m2) followed by infusion of unpurged autologous bone marrow and/or blood cells. All patients had advanced stage or bulky disease at diagnosis and failed to achieve a CR after an anthracycline-containing front-line chemotherapy regimen (NHL) or ABVD or equivalent regimen (HD). Patients who achieved a CR after involved-field radiotherapy were excluded. All patients demonstrated sensitivity to conventional-dose salvage treatment before advancing to intensive therapy and ABMT.

RESULTS

The CR, partial response (PR) and overall response rate (RR) following ABMT for HD patients was 48%, 17% and 65%, respectively. At a median follow-up of 35 months, the predicted three-year overall survival (OS) is 51% (95% CI: 44%-60%) and event-free survival (EFS) is 34% (95% CI: 26%-54%). For patients with NHL, the CR, PR and RR were 68%, 9% and 77%, respectively. At a median follow-up of 28 months, the predicted three-year OS is 51% (95% CI: 35%-66%) and EFS is 39% (95% CI: 21%-57%).

CONCLUSIONS

Intensive therapy with etoposide and melphalan followed by ABMT results in prolonged survival in selected patients with lymphoma who fail to achieve a complete remission to front-line chemotherapy. Based on our previous studies of outcome to conventional-dose salvage chemotherapy, we estimate that of all patients failing induction therapy, 28% with HD and 15% with NHL will be event-free at three years after ABMT.

GM-CSF accelerates neutrophil recovery after autologous hematopoietic stem cell transplantation

Patients with non-myeloid hematologic malignancies (including Hodgkin's and non-Hodgkin's lymphomas, myeloma and acute lymphoid leukemia) or solid tumors underwent cytoreductive conditioning regimens followed by either autologous bone marrow transplantation (ABMT) (n = 343) or transplantation of peripheral blood stem cells (PBSC) with (n = 44) or without bone marrow (BM) (n = 16). In a randomized double-blind phase III multi-center trial, patients received either granulocyte-macrophage colony-stimulating factor (GM-CSF, 10 micrograms/kg/day) or placebo by daily i.v. infusion beginning 24 h after bone marrow infusion and continuing until the absolute neutrophil count (ANC) had recovered to > or = 1000/mm3, or for a maximum of 30 days. Median time to neutrophil recovery was significantly shorter in the GM-CSF group (18 vs 27 days, P < 0.001), and more GM-CSF patients had neutrophil recovery by day 30 (70 vs 48%). Median duration of hospitalization was significantly shorter in the GM-CSF group (29 vs 32 days, P = 0.02). GM-CSF significantly reduced the median time to neutrophil recovery in patients receiving bone marrow only (19 vs 27 days, P < 0.001) or PBSC with or without bone marrow (14 vs 21 days, P < 0.001). The overall incidence of adverse events was comparable in the two groups, although more patients in the GM-CSF group discontinued treatment due to adverse events (17 vs 9%, P < 0.001). No difference was noted in infection incidence or time to platelet independence. GM-CSF had no negative impact on time to relapse or long-term survival. These data indicate the positive influence of GM-CSF on neutrophil recovery and hospital stay in patients receiving ABMT for a variety of clinical indications.

HLA-identical sibling bone marrow transplants vs chemotherapy for acute myelogenous leukemia in first remission

There is controversy whether adults with acute myelogenous leukemia (AML) in first remission are best treated with chemotherapy or an HLA-identical sibling bone marrow transplant. We studied 1097 adults, 16-50 years old, with AML in first remission. Results of transplants from HLA-identical siblings reported to the International Bone Marrow Transplant Registry (IBMTR; n = 901) were compared with results of chemotherapy in comparable persons treated by the German AML Cooperative Group (GAMLCG; n = 196). Preliminary analyses identified subject- and disease-related variables differing between the cohorts and associated with treatment outcome within each cohort. We adjusted for these variables and differences in time-to-treatment in subsequent comparisons of treatment-related mortality, relapse, survival and leukemia-free survival (LFS). Five-year probability of treatment-related mortality was greater for transplants than chemotherapy (43% (95% confidence interval, 37-49%) vs 7% (3-11%); P< 0.0001). Five-year relapse probability was less for transplants than chemotherapy (24% (20-28%) vs 63% (55-71%); P< 0.0001). Five-year probability of survival was similar with transplants and chemotherapy (48% (43-53%) vs 42% (33-51%); P = 0.24). Five-year LFS probability was higher for transplants than chemotherapy (46% (42-50%) vs 35% (28-41%); P= 0.01). These data indicate that bone marrow transplants from HLA-identical siblings result in comparable survival but greater LFS than chemotherapy in adults with AML in first remission.

Human hematopoiesis in SCID mice implanted with human adult cancellous bone

The persistence of hematopoietic cells from human adult cancellous bone fragments implanted subcutaneously into CB-17 scid/scid mice was studied. Recipient mice received either no pretreatment (control group) or pretreatment with 3 Gy total-body irradiation and anti-asialo GM1 sera (ASGM1; pretreated group) before implantation. Pretreated severe combined immunodeficient (SCID) mice implanted with human bone were subsequently given ASGM1 every 7 days for the duration of the experiments. At 12 weeks postimplantation, flow cytometry of cells from pretreated and control animal tissues detected human CD45+ cells in the mouse spleen (mean, 7.8% and 3.4% positive cells, pretreated and control animals, respectively), bone marrow (BM; mean, 16.5% and 4.8% positive cells, respectively), and blood (mean, 5.5% and < 2% positive cells, respectively), and in the implanted human bone (73% and 8.9% positive cells, respectively). At 12 weeks, pretreated mice had human granulocyte-macrophage colony-forming cells (GM-CFC) and burst-forming units-erythrocyte (BFU-E) in the implanted human bone in the murine BM and in some of the spleens. The spleens also had extensive infiltration of human B cells and macrophages. Mean serum levels of human IgG in pretreated animals were 14 micrograms/mL during weeks 6 to 12, compared with trace levels (< 1 microgram/mL) in control mice. Bone from patients with acute myeloblastic leukemia (AML) was also implanted in pretreated SCID mice, and retrieved at 8 weeks for analysis. Comparison of preimplantation and implanted samples showed that the original histology was maintained, and massive infiltration of human CD68+ cells was observed in the mice spleens and BM. Implantation of AML bone in SCID mice facilitates analysis of in situ AML cell interaction with stromal cells in the leukemic state, and therapies against AML can be tested in this system, especially the selective killing of AML cells in the presence of other BM cells. Furthermore, this model requires no exogenous administration of cytokines to maintain human hematopoiesis with both normal or AML bone. Because the structure and function of both normal and diseased human adult bone is maintained, this animal model should facilitate investigation of both normal human hematopoiesis and hematopoietic malignancies.

Acute leukemia in adults

Several trends are emerging in the treatment and investigation of acute leukemia in adults; in this review both of these aspects are addressed. Chemotherapy forms the mainstay of treatment for acute myeloblastic leukemia. In the past year, groups reported on the value of dose intensification in patients with acute myeloblastic leukemia under the age of 60 years and on the role of intensive chemotherapy combined with growth factors in the treatment of elderly patients. Similarly, the role of autologous bone marrow transplantation for older patients has been studied. Improvements in the treatment of patients with acute leukemia are likely to come from a recognition and understanding of the biologic attributes of the leukemic cell. Failure to cure leukemia is likely due to failure to eradicate the leukemic clone. Mechanisms of drug resistance acting before the drug reaches its target (proximal resistance) and after the drug interacts with its target (distal resistance) are gaining greater importance in understanding treatment failures. Advances have been made in identifying new mechanisms that are involved in proximal as well as distal drug resistance. Genetic changes both at the cytogenetic and the molecular level identify different FAB subgroups and groups of patients with good and bad prognostic features. Finally, reports are reviewed of two new factors that stimulate the growth of acute myeloblastic leukemia cells (thrombopoietin and Flt3 ligand) and a factor that inhibits the autocrine growth characteristics of acute myeloblastic leukemia cells (interleukin-10). The results of these interface and basic studies offer the hope of identifying groups of patients with different therapeutic needs and suggest ways to develop therapies aimed at the biology of the leukemic cell.

Bead transfection of adherent cells. Gene transfer into adherent mammalian cells using glass beads

Bead transfection is a simple, rapid, efficient, and cost-effective method of gene transfer into adherent mammalian cells. It involves a brief incubation of the cells with glass beads in a solution containing the DNA to be transferred. We have optimized this technique using COS-7 (an SV40 transformed monkey kidney cell line) and a transient expression assay for chloramphenicol acetyl transferase (CAT). Stable transfection efficiency assessed using the selectable marker gene neomycin phosphotransferase (NEOR) was 27% in COS-7 cells. As this technique delivers high transfection efficiency with little manipulation of the exogenous DNA and does not require the use of any viral sequences, it may be a useful alternative method of gene delivery in the development of gene therapy protocols.

Blood stem cell collection: factors influencing the recovery of granulocyte-macrophage colony forming cells

We evaluated data from all blood cell (BC) collections performed in our institution between 1989 and 1995 to determine factors influencing the outcome of collection. One hundred and thirty-three collections were performed on 106 patients. Malignant diagnoses were: non-Hodgkins lymphoma (NHL) in 35%, multiple myeloma in 31%, breast cancer in 26%, and Hodgkin's disease in 8%. Collections were obtained routinely in myeloma and breast cancer and due to bone marrow involvement with malignancy or inaspirable bone marrow in lymphoma patients. Collections were obtained on a Cobe Spectra or Baxter-Fenwall CS3000+. Engraftment potential was determined by methylcellulose colony assay (CFU-GM), with a target of > 10 x 10(4) CFU-GM/kg. Apheresis nucleated cell count correlated significantly, albeit weakly (r = 0.26), with CFU-GM with a cell count of > 5 x 10(8)/kg resulting in an adequate number of CFU-GM in 78% of patients. In univariant analysis outcome of collection was significantly influenced by the patients age (p = 0.01), malignant diagnosis (p < 0.001), reason for collection (p = 0.002), and the mobilization regimen (p = 0.01). The nature of the apheresis device used did not influence outcome. Only malignant diagnosis was significant (p < 0.001) in multivariate analysis. We conclude that the outcome of BC is most strongly influenced by patient factors such as malignant diagnosis. These factors must be considered when comparing the outcome of different mobilization regimens and when planning collection strategies.

The hematopoietic stem cell in elderly patients with leukemia

Stem cell reserve and the proliferative capacity of pluripotent hematopoietic progenitors as influenced by age are of intrinsic biologic interest and potential therapeutic importance. The latter is especially true in older persons receiving intensive but not marrow-ablative chemotherapy. Studies of stem cell aging using murine models yield conflicting data. Unfortunately, few studies address the effect of aging on human hematopoietic stem cells, largely because there is no true pluripotent stem cell assay. Some work indicates that the proliferative capacity of human hematopoietic stem cells appears to decrease with age but is unclear whether this is of clinical significance. Our preliminary analysis of more than 500 autotransplant candidates by univariate analysis indicates that higher patient age correlates with reduced committed hematopoietic progenitor cell levels but not with delayed engraftment. In the future, the use of combinations of assays that include phenotypic (CD34+thy1+CD38lo) and functional (long-term culture-initiating cell) characteristics may better identify the effects of aging on candidate stem cells. The development of assays that predict delayed hematopoietic recovery after chemotherapy in older adults may help to tailor therapy for specific patients with the hope of reducing morbidity while retaining efficacy.

Peripheral blood progenitor cell collections in multiple myeloma: predictors and management of inadequate collections

Thirty-seven patients with previously treated multiple myeloma (MM) underwent peripheral blood progenitor cell (PBPC) collection following high-dose cyclophosphamide and GM-CSF or sequential IL-3 and GM-CSF. Patients with an inadequate collection were considered for a second or third collection. 25 patients underwent subsequent autotransplant. The only variable predictive of CFU-GM yield was the extent of prior melphalan therapy. All repeat collections were unsuccessful and patients infused with an autograft obtained from multiple sets of collections had a high incidence of delayed engraftment. We conclude that melphalan should be avoided or PBPC collection performed early in the disease course in patients who are potential transplant candidates.