This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stewart, A. K. Articles by Berenson, J. Search for Related Content PubMed PubMed Citation Articles by Stewart, A. K. Articles by Berenson, J. Social Bookmarking                            What's this?

Purging of Autologous Peripheral-Blood Stem Cells Using CD34 Selection Does Not Improve Overall or Progression-Free Survival After High-Dose Chemotherapy for Multiple Myeloma: Results of a Multicenter Randomized Controlled Trial

From the Princess Margaret Hospital, Toronto, Ontario, Canada; West Los Angeles Veterans Affairs Medical Center/University of California at Los Angeles, and Southern California Kaiser Permanente Medical Group, Los Angeles; University of California at San Francisco, San Francisco, CA; University of South Florida, Miami, FL; Johns Hopkins University, Baltimore, MD; University of Texas at San Antonio, San Antonio, TX; University of Pennsylvania, Philadelphia, PA; University of Nebraska, Omaha, NE; Loyola University, Chicago, IL; Washington University School of Medicine, St Louis, MO; Dana-Farber Cancer Institute, Boston, MA; and CellPro, Inc, Bothell, WA.

Address reprint requests to A. Keith Stewart, MBCHB, Princess Margaret Hospital, 610 University Ave, Rm 5-126, Toronto, Ontario, Canada M5G 2M9; email: k.stewart{at}uhnres.utoronto.ca

	ABSTRACT

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
PURPOSE: Although high-dose chemotherapy supported by autologous peripheral-blood progenitor-cell (PBPC) transplantation improves response rates and survival for patients with multiple myeloma, all patients eventually develop progressive disease after transplantation. It has been hypothesized that depletion of malignant plasma cells from autografts may improve outcome by reducing infused cells contributing to relapse.

PATIENTS AND METHODS: A randomized phase III study using the CEPRATE SC System (Cellpro, Bothell, WA) to enrich CD34⁺ autograft cells and passively purge malignant plasma cells was completed in 190 myeloma patients randomized to receive an autograft of CD34-selected or unselected PBPCs.

RESULTS: After CD34 selection, tumor burden was reduced by 1.6 to 6.0 logs (median, 3.1), with 54% of CD34-enriched products having no detectable tumor. Median time to count recovery, number of transfusions, transplantation-related mortality, and days in hospital were equivalent between the two transplantation arms. With a median follow-up of 37 months, 33 patients (36%) in the selected and 34 patients (35%) in the unselected arm had died (P = .784). Median overall survival in the selected arm was reached at 50 months and is not reached at this time in the unselected arm (P = .78). Median disease-free survival was 100 versus 104 weeks (P = .82), with 67% of patients in the selected arm and 66% of patients in the unselected arm relapsing.

CONCLUSION: This phase III trial demonstrates that although CD34 selection significantly reduces myeloma cell contamination in PBPC collections, no improvement in disease-free or overall survival was achieved.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
TREATMENT OF MULTIPLE myeloma with myeloablative therapy and autologous peripheral-blood progenitor-cell (PBPC) transplantation improves response rates, disease-free survival, and overall survival in younger patients when compared with conventional multiagent chemotherapy regimens.^1-3 Nevertheless, the vast majority of patients receiving high-dose therapy develop progressive disease, with a median time to relapse of approximately 3 years.³ Because multiple myeloma is characterized by an accumulation of monoclonal plasma cells in the bone marrow and by the presence of circulating malignant cells, PBPC autografting results in the reinfusion of myeloma cells.^4-6 The consequences of reinfusing malignant cells are currently unknown, as gene marking studies have to date not been informative in this disease.^7,8 One prospective study has previously reported that the presence of circulating myeloma cells in PBPC grafts correlates with poor outcome after transplantation.⁹ It has therefore been postulated that removing malignant cells from the autograft may improve survival rates, and a number of approaches have been developed aimed at purging contaminating myeloma cells from the graft before PBPC reinfusion.^10-12

One such approach is the positive selection of hematopoietic stem cells expressing CD34 using the CEPRATE SC Column (Cellpro, Bothell, WA).¹³ Because the dominant malignant clone in multiple myeloma does not generally express CD34,^14-17 positive selection of CD34-positive cells in autografts should reduce myeloma cell contamination.^18,19 In preliminary phase II studies of 37 myeloma patients receiving CD34-selected PBPCs, neutrophil and platelet engraftment were rapid (median, 12 days for both) and sustained if a dose of at least 2 x 10⁶ CD34 cells/kg was infused.²⁰ To further explore the safety and efficacy of CD34 selection as a purging modality, a phase III randomized, controlled, unblinded and multicenter trial was conducted.²¹ We have previously reported on the primary end points of this study by examining a cohort of 131 patients randomized to receive either CD34-selected PBPC cells or unmanipulated PBPC products. Hematologic and immunologic recovery after transplantation was essentially identical in both arms of the study. Purging efficacy of CD34 selection was also examined, and a statistically significant decline in tumor burden in the selected autografts was evident.²¹

Here we report an extension of that study to a total of 190 randomized patients and focus on the influence of purging on survival end points. At a median follow-up of 37 months, we demonstrate here that purging of myeloma autografts by CD34 selection does not prolong disease-free or overall survival after high-dose chemotherapy.

	PATIENTS AND METHODS

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
Study Design
One hundred ninety-three patients with multiple myeloma 70 years of age or younger were enrolled onto a phase III open-label, randomized trial at 15 sites in North America. Sample size was determined using a 90% power to detect a reduction of 12% in the percentage of patients with successful neutrophil engraftment by day 14 posttransplantation, assuming that 95% of patients in the unselected arm achieve neutrophil engraftment by day 14. Although not designed with disease-free survival as a primary end point, the hazards ratio for this sample size is 1.65 with a power of 80%, alpha = 0.05, or approximately an 18% difference in disease-free survival at 3 years. The hazards ratio for overall survival with 80% power is 1.99, or a difference in survival at 3 years of 20%. The study design was approved by the institutional review boards of all participating institutions and by the United States Food and Drug Administration under an investigational device exemption. All patients gave written informed consent to participate. All patients had a diagnosis of multiple myeloma Durie-Salmon stage II or III. Patients were required to have stable or responsive disease after a minimum of three cycles of standard-dose chemotherapy. Patients who had received more than 3 months of alkylator-based therapy, greater than 6 months of any other prior chemotherapy, or who exhibited disease progression at any time were ineligible for study entry. Figure 1 shows a schema of the study. Collection of autologous PBPCs occurred within 3 weeks of the patient’s evaluation for eligibility. The mobilization regimen consisted of cyclophosphamide 2.5 g/m² administered intravenously on the first day of mobilization, prednisone 2 mg/kg/d administered orally on the first 4 days, and granulocyte colony-stimulating factor (G-CSF) 10 µg/kg/d administered subcutaneously beginning on the second day and continuing until the last day of leukapheresis. Before leukapheresis, patients were randomized to receive either CD34-selected (the selected arm) or unselected PBPCs (the unselected arm). Randomization was stratified by patient age (using 55 years as a cutoff) and site. According to the protocol, the first 58 patients (28 in the selected arm and 30 in the unselected arm) began leukapheresis no sooner than day 15 of PBPC mobilization and had to have a WBC count 1,000/µL on two occasions more than 24 hours apart and a platelet count 30,000/µL. This schema was chosen based on results of prior phase II trials. Because of concerns that peak collection times were being missed, the remaining 76 patients began leukapheresis as soon as the hematologic parameters outlined above were met. Leukapheresis was performed daily until at least 5.0 x 10⁸ nucleated cells/kg were obtained (minimum of 2 days). For patients randomized to receive a CD34-selected autograft, there was an additional stopping criteria of at least 4.0 x 10⁶ nucleated cells/kg in the selected product after processing. This was based on the assumption that the selected product would contain at least 50% CD34⁺ cells. After completing PBPC collection, patients received a myeloablative high-dose chemotherapy regimen consisting of busulfan and cyclophosphamide. A total dosage of 14 mg/kg of busulfan (0.875 mg/kg administered orally four times daily for 4 days) and 120 mg/kg of cyclophosphamide (60 mg/kg administered intravenously daily for 2 days) was administered to all patients. Patients received the thawed CD34-selected or unselected products 2 days after the last infusion of cyclophosphamide. To speed hematologic recovery, granulocyte-macrophage colony-stimulating factor (GM-CSF) at 250 µg/m² (maximum of 500 µg) was administered daily until the patient’s absolute neutrophil count was at least 1,000/µL for 2 consecutive days. Each site used its own standardized supportive care protocols for patients on both arms of the study.

View larger version (19K): [in this window] [in a new window]   Fig 1. Schema of study design. Eligible patients were registered and PBPCs were mobilized. Before initiating leukapheresis, patients were randomized to one of the two treatment arms. All patients received high-dose chemotherapy followed by an infusion of either CD34-selected or unselected PBPCs, with GM-CSF administered posttransplantation. Reprinted with permission.21

Leukapheresis, Cell Processing, and Cryopreservation
Autologous PBPCs were obtained by continuous-flow leukapheresis using a Cobe Spectra (Cobe, Lakewood, CO). Blood volume processed per run was 10 L. Patients randomized to receive unselected PBPCs each had individual leukapheresis products cryopreserved in 10% dimethyl sulfoxide by controlled-rate freezing and stored in the vapor phase of liquid nitrogen. Patients randomized to receive CD34-selected PBPCs had each individual leukapheresis product selected using the CEPRATE SC System according to the manufacturer’s protocol. The CD34-selected PBPCs were then cryopreserved in 7.5% dimethyl sulfoxide by controlled-rate freezing and stored in the vapor phase of liquid nitrogen.

Myeloma Immunoglobulin Gene Identification
The immunoglobulin (Ig) heavy-chain variable region (VH) or light-chain variable region (VL; in light-chain–only secreting tumors) sequence expressed by the myeloma clone was determined by polymerase chain reaction (PCR) using a bone marrow aspirate obtained from each patient at study entry (study entry occurred before PBPC collection, not at diagnosis). When present, the predominant, appropriately sized PCR product was excised from an agarose gel impregnated with ethidium bromide, cloned, and sequenced by methods previously described. A minimum of three identical clones of five was required to assign an Ig sequence to the myeloma cell. The VH and VL myeloma gene sequences were compared (DNAsis; Hitachi, San Bruno, CA) with known germline gene segments. All data regarding identification of the malignant clone and the efficacy of purging as assessed by reverse transcriptase PCR have been previously reported by Vescio et al.²¹

Assessment and Quantification of Tumor Contamination
Tumor contamination of PBPC grafts was determined using a PCR assay as previously described.²¹ Patient-specific oligonucleotides (Operon, Alameda, CA) were designed complementary to the most unique myeloma Ig gene sequences in both the sense (CDR1 or CDR2) and antisense orientation (CDR3). DNA was then extracted from bone marrow and peripheral-blood mononuclear cells, unselected leukapheresis products, and CD34-selected and CD34-depleted PBPCs products using standard techniques. PCR conditions were optimized using the PCR Optimizer Kit (Invitrogen, San Diego, CA) on bone marrow DNA diluted 100-fold with 0.6 µg of placental DNA. Sixty cycles of amplification were performed with Taq polymerase. To quantify the tumor cell contamination, multiple PCR reactions were performed with sample DNA serially diluted in 0.5-log increments with placental DNA. Five reactions were performed at each serial dilution until PCR products were no longer detectable. Tumor contamination was calculated by a Poisson distribution analysis of positive and negative reactions at each serial dilution. Amplification of tubes containing a diluted bone marrow specimen (positive), placental DNA (negative), and water only (negative) using the patient-specific primers served as controls for each assay. To reduce assay-to-assay variability, the leukapheresis product and CD34-selected product collected from the same patient were amplified simultaneously in the same PCR machine. All PCR products were electrophoresed through ethidium bromide–impregnated agarose gels, photographed, and scored in triplicate by technicians blinded to sample identification. The validation of the PCR tumor detection assay and statistical derivation of the tumor cell contamination has been reported previously.²¹

Statistical Methods
The statistical analyses and summaries were provided for the intent-to-treat population, defined as all patients who were randomized to treatment. Comparisons between the treatment arms in terms of the demographic baseline data were performed using the two-sample t test or Wilcoxon rank sum test for continuous data and Fisher’s exact test for categorical data. Survival time and progression-free survival time were calculated from the date of transplantation and summarized using Kaplan-Meier curves. For patients who experienced disease progression or died, progression-free survival time was calculated as the date of progression (or death) minus the date of transplantation. For the remaining patients, progression-free survival time was calculated as the date of last contact minus the date of transplantation. The arms were compared with respect to survival time using the Wald ² statistic from the Cox proportional hazards model. The effect of each disease-related variable on outcome was investigated independently using the Wald ² statistic from univariate Cox (single-regressor variable) proportional hazards regression models at a 0.05 level of significance (alpha = 0.05). The variables identified as having a significant effect on response were used in a multiple regression analysis. Sex by treatment interactions were examined and no effect was noted.

	RESULTS

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
Patient Demographics and Baseline Risk Factors
Between January 1995 and June 1996, 193 patients were enrolled at 15 sites throughout North America. Three patients were not randomized: one patient elected to receive an allogeneic transplantation, another patient died before randomization, and the third developed disease progression before randomization. There were therefore 190 patients randomized in the intent-to-treat population, and 188 patients underwent transplantation. Two patients in the CD34-selected arm withdrew consent before transplantation. The treatment arms were equivalent at the time of the premobilization registration visit with respect to age, performance status, disease remission status, hemoglobin, WBC, total lymphocyte or platelet counts, beta-2 microglobulin levels, C-reactive protein, serum immunoglobulin isotype and level, and the number of previous cycles of chemotherapy (Table 1). There was a significantly higher proportion of females in the selected arm (47% v 30%; P = .014). There was no difference on the day of randomization between the absolute levels of circulating CD4⁺, CD19⁺, or CD56⁺ cells (data not shown); however, a lower median CD4/CD8 ratio (1.4 v 1.7; P = .063) and the higher median CD8 count (421/µL v 330/µL; P = .069) in the selected arm approached significance.

Tumor Purging Efficacy of the CEPRATE SC System
Bone marrow samples were obtained at the time of study registration from the first 130 randomized patients. As previously described, a clonal Ig sequence was identified and used in the analysis for 47 patients: 28 in the selected arm and 19 in the unselected arm.²¹ The data are reprinted here for completeness. A clonal Ig sequence was not identified for 81 patients (36 in the selected arm and 45 in the unselected arm) for the following reasons: normal serum protein electrophoresis and urine protein electrophoresis at study entry (n = 22), ineffective (n = 19) or polyclonal (n = 24) Ig gene amplification, and inadequate (n = 12) or unavailable (n = 4) bone marrow specimens. In addition, there were three patients who had clonal Ig gene sequences identified who were not included in the analyses: for two patients, PCR conditions could not be adjusted to specifically amplify only the myeloma Ig gene product, and one patient did not have samples obtained from leukapheresis products. A median of 2.6 x 10⁶ and 2.3 x 10⁶ tumor cells were detected in the initial leukapheresis product of patients in the selected and unselected arms, respectively. One primary efficacy end point of the study was a greater than 2 log reduction in tumor cell contamination after CD34 selection using the CEPRATE SC System. This was evaluated in 24 patients in the selected arm for whom a clonal Ig sequence could be identified and who had detectable tumor cells in the PBPC product before CD34 selection (Table 2). Twenty-two (92%) of 24 patients achieved greater than 2 logs depletion and 11 (46%) of 24 had no detectable tumor cells in the selected product. To estimate the log depletion of tumor cells for these samples, the minimal detection limit of the assay (1:700,000) was used as the percentage of tumor cells in the selected population. Thus the mean and median log depletion of tumor cells obtained by CD34 selection is an underestimate. A median 3.10-log (mean, 3.29 log) depletion of tumor cells was achieved by the CEPRATE SC system in the selected arm (range, 1.56 to 6.02 logs). The number of tumor cells infused was significantly lower in the selected arm (median, 0; range, 0 to 1.2 x 10⁶) compared with the unselected arm (median, 2.3 x 10⁶; range, 0 to 930 x 10⁶). Overall, the number of patients in the CD34-selected arm who received an autograft with no detectable tumor cells (15 of 28) was significantly greater than those receiving an unselected leukopheresis product (54% v 21%; P = .036).

View larger version (26K): [in this window] [in a new window]   Fig 2. Kaplan-Meier probability of progression-free survival of 188 patients stratified on an intent-to-treat basis.

View larger version (26K): [in this window] [in a new window]   Fig 3. Kaplan-Meier probability of overall survival of 188 patients stratified on an intent-to-treat basis.

	DISCUSSION

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

We report here the results of the first prospective randomized controlled trial to examine the influence on survival of purging autografts in myeloma patients. PBPC grafts were passively purged using the CEPRATE SC CD34 selection device which concentrates normal CD34 positive hematopoietic progenitor cells. As previously reported, patients randomized to the selected arm received 3.3 logs fewer infused tumor cells than the unselected arm.²¹ Where PCR-detectable myeloma cells were eliminated in CD34 selected samples, the minimum detection limit of the PCR assay was used in calculations of tumor cells infused. Consequently, the data we have reported are, if anything, likely to be an underestimate of purging efficacy.

As previously reported, purging was achieved without adversely affecting the ability of the hematopoietic stem cells to restore hematopoiesis. Time to neutrophil engraftment was not significantly different between the two arms. Time to platelet engraftment was positively related to numbers of CD34 cells infused (higher CD34 cells, shorter time to engraft) and although platelet recovery after transplantation was statistically slower in the selected arm of this trial, the difference was not clinically relevant.²¹ Patients receiving a CD34-selected autograft also had a lower incidence of toxicities associated with the autograft infusion and had no greater incidence of infections or bleeding events when compared with patients receiving an unselected autograft. Thus CD34 selection is safe, results in lower infusion-related toxicities,³⁰ and successfully purges PBPC grafts of contaminating myeloma cells.

Despite the successful depletion of tumor cells in the processed grafts, at a median follow-up of 37 months posttransplantation, disease-free or overall survival was not significantly different between the CD34-selected and unselected arms. The most likely explanation for this finding is a failure to eradicate myeloma cells in the host with high-dose chemoradiotherapy. This conclusion is supported by studies examining long-term follow-up of myeloma patients undergoing allogeneic, and thus tumor-free, transplantation in which only nine (7.4%) of 121 patients were alive and disease-free at 4 years posttransplantation.³¹ Thus, because myeloma is relatively resistant to current high-dose chemotherapeutic regimens, the use of purged autologous PBPC transplants cannot be recommended until protocols are developed that markedly reduce the residual host tumor burden. In the trial reported here, median relapse-free survival was 102 weeks (2 years), whereas median overall survival was 202 weeks (4 years). These figures are somewhat lower than those reported in other phase III trials of early transplantation¹ and may reflect the transplantation conditioning regimens used or the lack of maintenance therapy employed.

Eradicating residual tumor cells resistant to the effects of high-dose chemotherapy is therefore an important focus of current clinical research. Increasing the intensity of myeloablative chemoradiotherapy using standard chemotherapy agents before stem-cell transplantation does not seem to be a fruitful strategy at this time, as increased toxicity rates seem to balance any survival advantages conferred.³² Some new approaches to improved myeloablative therapy (eg, using bone marrow–targeted radiotherapy) are now under study and may overcome the limitations to dose-escalated therapy conferred by toxicity.³³ Increasing the number or timing of autologous transplantation procedures has also been advocated, and although it has not yet been convincingly demonstrated to improve outcome in myeloma patients,³ randomized trials evaluating this tandem transplantation approach are advanced. An alternative strategy of posttransplantation maintenance chemotherapy aimed at eliminating minimal residual disease is also being applied in many centers using conventional chemotherapies, novel agents such as thalidomide, or immune-based myeloma vaccine strategies. If such approaches do indeed improve remission rates and survival in myeloma patients undergoing high-dose chemotherapy, PBPC purging may once again emerge as an important strategy in myeloma therapy. To this end, a number of novel purging techniques have recently been developed that enhance the efficacy of current purging technologies.^10-12

In conclusion, use of CD34 selection as a purging modality has no general utility in prolonging disease-free or overall survival in multiple myeloma patients undergoing intensive therapy with PBPC support at this time.

	ACKNOWLEDGMENTS

 
Supported by CellPro, Inc. Support for updated statistical analysis was provided by Baxter Health Care, Deerfield, IL.

We thank Brian Clark, PhD, for assistance with manuscript preparation.

	REFERENCES

TOP ABSTRACT INTRODUCTION PATIENTS AND METHODS RESULTS DISCUSSION REFERENCES

 
1. Attal M, Harousseau JL, Stoppa AM, et al: A prospective, randomized trial of autologous bone marrow transplantation and chemotherapy in multiple myeloma: Intergroupe Francais du Myelome. N Engl J Med 335: 91-97, 1996[Abstract/Free Full Text]

2. Barlogie B, Jagannath S, Desikan KR, et al: Total therapy with tandem transplants for newly diagnosed multiple myeloma. Blood 93: 55-65, 1999[Abstract/Free Full Text]

3. Desikan R, Barlogie B, Sawyer J, et al: Results of high-dose therapy for 1000 patients with multiple myeloma: Durable complete remissions and superior survival in the absence of chromosome 13 abnormalities. Blood 95: 4008-4010, 2000[Abstract/Free Full Text]

4. Schneider U, van Lessen A, Huhn D, et al: Two subsets of peripheral blood plasma cells defined by differential expression of CD45 antigen. Br J Haematol 97: 56-64, 1997[Medline]

5. Kay NE, Leong T, Kyle RA, et al: Circulating blood B cells in multiple myeloma: Analysis and relationship to circulating clonal cells and clinical parameters in a cohort of patients entered on the Eastern Cooperative Oncology Group phase III E9486 clinical trial. Blood 90: 340-345, 1997[Abstract/Free Full Text]

6. Zandecki M, Bernardi F, Genevieve F, et al: Involvement of peripheral blood cells in multiple myeloma: Chromosome changes are the rule within circulating plasma cells but not within B lymphocytes. Leukemia 11: 1034-1039, 1997[Medline]

7. Stewart AK, Sutherland DR, Nanji S, et al: Engraftment of gene-marked hematopoietic progenitors in myeloma patients after transplant of autologous long-term marrow cultures. Hum Gene Ther 10: 1953-1964, 1999[Medline]

8. Dunbar CE, Cottler-Fox M, O’Shaughnessy JA, et al: Retrovirally marked CD34-enriched peripheral blood and bone marrow cells contribute to long-term engraftment after autologous transplantation. Blood 85: 3048-3057, 1995[Abstract/Free Full Text]

9. Gertz MA, Witzig TE, Pineda AA, et al: Monoclonal plasma cells in the blood stem cell harvest from patients with multiple myeloma are associated with shortened relapse-free survival after transplantation. Bone Marrow Transplant 19: 337-342, 1997[Medline]

10. LaCasse EC, Bray MR, Patterson B, et al: Shiga-like toxin-1 receptor on human breast cancer, lymphoma, and myeloma and absence from CD34(+) hematopoietic stem cells: Implications for ex vivo tumor purging and autologous stem cell transplantation. Blood 94: 2901-2910, 1999[Abstract/Free Full Text]

11. Lemoli RM, Martinelli G, Olivieri A, et al: Selection and transplantation of autologous CD34+ B-lineage negative cells in advanced-phase multiple myeloma patients: A pilot study. Br J Haematol 107: 419-428, 1999[Medline]

12. Teoh G, Chen L, Urashima M, et al: Adenovirus vector-based purging of multiple myeloma cells. Blood 92: 4591-4601, 1998[Abstract/Free Full Text]

13. Shpall EJ, Jones RB, Bearman SI, et al: Positive selection of CD34+ hematopoietic progenitor cells for transplantation. Stem Cells 11: 48-49, 1993 (suppl 3)

14. Vescio RA, Hong CH, Cao J, et al: The hematopoietic stem cell antigen, CD34, is not expressed on the malignant cells in multiple myeloma. Blood 84: 3283-3290, 1994[Abstract/Free Full Text]

15. Lemoli RM, Fortuna A, Motta MR, et al: Concomitant mobilization of plasma cells and hematopoietic progenitors into peripheral blood of multiple myeloma patients: Positive selection and transplantation of enriched CD34+ cells to remove circulating tumor cells. Blood 87: 1625-1634, 1996[Abstract/Free Full Text]

16. Willems P, Croockewit A, Raymakers R, et al: CD34 selections from myeloma peripheral blood cell autografts contain residual tumour cells due to impurity, not to CD34+ myeloma cells. Br J Haematol 93: 613-622, 1996[Medline]

17. Szczepek AJ, Bergsagel PL, Axelsson L, et al: CD34+ cells in the blood of patients with multiple myeloma express CD19 and IgH mRNA and have patient-specific IgH VDJ gene rearrangements. Blood 89: 1824-1833, 1997[Abstract/Free Full Text]

18. Rasmussen T, Jensen L, Honore L, et al: Circulating clonal cells in multiple myeloma do not express CD34 mRNA, as measured by single-cell and real-time RT-PCR assays. Br J Haematol 107: 818-824, 1999[Medline]

19. Gazitt Y, Reading CC, Hoffman R, et al: Purified CD34+ Lin- Thy+ stem cells do not contain clonal myeloma cells. Blood 86: 381-389, 1995[Abstract/Free Full Text]

20. Schiller G, Vescio R, Freytes C, et al: Transplantation of CD34+ peripheral blood progenitor cells after high- dose chemotherapy for patients with advanced multiple myeloma. Blood 86: 390-397, 1995[Abstract/Free Full Text]

21. Vescio R, Schiller G, Stewart AK, et al: Multicenter phase III trial to evaluate CD34(+) selected versus unselected autologous peripheral blood progenitor cell transplantation in multiple myeloma. Blood 93: 1858-1868, 1999[Abstract/Free Full Text]

22. Billadeau D, Van Ness B, Kimlinger T, et al: Clonal circulating cells are common in plasma cell proliferative disorders: A comparison of monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, and active myeloma. Blood 88: 289-296, 1996[Abstract/Free Full Text]

23. Mohr M, Hilgenfeld E, Fietz T, et al: Efficacy and safety of simultaneous immunomagnetic CD34+ cell selection and breast cancer cell purging in peripheral blood progenitor cell samples used for hematopoietic rescue after high-dose therapy. Clin Cancer Res 5: 1035-1040, 1999[Abstract/Free Full Text]

24. Gribben JG, Neuberg D, Freedman AS, et al: Detection by polymerase chain reaction of residual cells with the bcl-2 translocation is associated with increased risk of relapse after autologous bone marrow transplantation for B-cell lymphoma. Blood 81: 3449-3457, 1993[Abstract/Free Full Text]

25. Rill DR, Santana VM, Roberts WM, et al: Direct demonstration that autologous bone marrow transplantation for solid tumors can return a multiplicity of tumorigenic cells. Blood 84: 380-383, 1994[Abstract/Free Full Text]

26. Brenner MK, Rill DR, Moen RC, et al: Gene-marking to trace origin of relapse after autologous bone-marrow transplantation. Lancet 341: 85-86, 1993[Medline]

27. Richkind KE, Loew T, Meisner L, et al: Identical cytogenetic clones and clonal evolution in pediatric monozygotic twins with acute myeloid leukemia: presymptomatic disease detection by interphase fluorescence in situ hybridization and review of the literature. J Pediatr Hematol Oncol 20: 264-267, 1998[Medline]

28. Osada S, Horibe K, Oiwa K, et al: A case of infantile acute monocytic leukemia caused by vertical transmission of the mother’s leukemic cells. Cancer 65: 1146-1149, 1990[Medline]

29. Penn I: Transmission of cancer from organ donors. Ann Transplant 2: 7-12, 1997[Medline]

30. Shpall EJ, LeMaistre CF, Holland K, et al: A prospective randomized trial of buffy coat versus CD34-selected autologous bone marrow support in high-risk breast cancer patients receiving high-dose chemotherapy. Blood 90: 4313-4320, 1997[Abstract/Free Full Text]

31. Bjorkstrand BB, Ljungman P, Svensson H, et al: Allogeneic bone marrow transplantation versus autologous stem cell transplantation in multiple myeloma: A retrospective case-matched study from the European Group for Blood and Marrow Transplantation. Blood 88: 4711-4718, 1996[Abstract/Free Full Text]

32. Abraham R, Chen C, Tsang R, et al: Intensification of the stem cell transplant induction regimen results in increased treatment-related mortality without improved outcome in multiple myeloma. Bone Marrow Transplant 24: 1291-1297, 1999[Medline]

33. Bayouth JE, Macey DJ, Kasi LP, et al: Pharmacokinetics, dosimetry and toxicity of holmium-166-DOTMP for bone marrow ablation in multiple myeloma. J Nucl Med 36: 730-737, 1995[Abstract/Free Full Text]

Submitted July 27, 2000; accepted May 7, 2001.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				J.-H. Bourhis, Y. Bouko, S. Koscielny, M. Bakkus, H. Greinix, G. Derigs, G. Salles, W. Feremans, J. Apperley, D. Samson, et al. Relapse risk after autologous transplantation in patients with newly diagnosed myeloma is not related with infused tumor cell load and the outcome is not improved by CD34+ cell selection: long term follow-up of an EBMT phase III randomized study Haematologica, August 1, 2007; 92(8): 1083 - 1090. [Abstract] [Full Text] [PDF]

				E. A. Copelan Hematopoietic stem-cell transplantation. N. Engl. J. Med., April 27, 2006; 354(17): 1813 - 1826. [Full Text] [PDF]

				D. Dingli, G. S. Nowakowski, A. Dispenzieri, M. Q. Lacy, S. R. Hayman, S. V. Rajkumar, P. R. Greipp, M. R. Litzow, D. A. Gastineau, T. E. Witzig, et al. Flow cytometric detection of circulating myeloma cells before transplantation in patients with multiple myeloma: a simple risk stratification system Blood, April 15, 2006; 107(8): 3384 - 3388. [Abstract] [Full Text] [PDF]

				R. A. Kyle and S. V. Rajkumar Multiple Myeloma N. Engl. J. Med., October 28, 2004; 351(18): 1860 - 1873. [Full Text] [PDF]

				B. Barlogie, J. Shaughnessy, G. Tricot, J. Jacobson, M. Zangari, E. Anaissie, R. Walker, and J. Crowley Treatment of multiple myeloma Blood, January 1, 2004; 103(1): 20 - 32. [Abstract] [Full Text] [PDF]

				J. Blade, D. H. Vesole, and M. Gertz Transplantation for multiple myeloma: who, when, how often? Blood, November 15, 2003; 102(10): 3469 - 3477. [Full Text] [PDF]

				D. G. Maloney, A. J. Molina, F. Sahebi, K. E. Stockerl-Goldstein, B. M. Sandmaier, W. Bensinger, B. Storer, U. Hegenbart, G. Somlo, T. Chauncey, et al. Allografting with nonmyeloablative conditioning following cytoreductive autografts for the treatment of patients with multiple myeloma Blood, November 1, 2003; 102(9): 3447 - 3454. [Abstract] [Full Text] [PDF]

				M. H. Cottler-Fox, T. Lapidot, I. Petit, O. Kollet, J. F. DiPersio, D. Link, and S. Devine Stem Cell Mobilization Hematology, January 1, 2003; 2003(1): 419 - 437. [Abstract] [Full Text] [PDF]

				L. M. Pilarski and A. R. Belch Clonotypic Myeloma Cells Able to Xenograft Myeloma to Nonobese Diabetic Severe Combined Immunodeficient Mice Copurify with CD34+ Hematopoietic Progenitors Clin. Cancer Res., October 1, 2002; 8(10): 3198 - 3204. [Abstract] [Full Text] [PDF]

				S. V. Rajkumar, M. A. Gertz, R. A. Kyle, P. R. Greipp, and Mayo Clinic Myeloma, Amyloid, and Dysproteinemia G Current Therapy for Multiple Myeloma Mayo Clin. Proc., August 1, 2002; 77(8): 813 - 822. [Abstract] [PDF]

				R. L. Comenzo and M. A. Gertz Autologous stem cell transplantation for primary systemic amyloidosis Blood, May 29, 2002; 99(12): 4276 - 4282. [Abstract] [Full Text] [PDF]

				D. G. Maloney, B. M. Sandmaier, S. Mackinnon, and J. A. Shizuru Non-Myeloablative Transplantation Hematology, January 1, 2002; 2002(1): 392 - 421. [Abstract] [Full Text]

This Article Abstract Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Save to my personal folders Download to citation manager Rights & Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stewart, A. K. Articles by Berenson, J. Search for Related Content PubMed PubMed Citation Articles by Stewart, A. K. Articles by Berenson, J. Social Bookmarking                            What's this?