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Retrospective Analysis of Autologous Peripheral Blood Stem Cell Mobilization Using G-CSF Including Biosimilar
S136
Abstracts / Biol Blood Marrow Transplant 22 (2016) S19eS481
received G+P between January 2011 and September 2014. Baseline characteristics were similar between the two groups. The mean CD34+ yield for the CDEA+G group was 30.95 x106 cells/kg (range, 14.32-67.29) compared with 22.39 x106 cells/ kg (range, 4.83-42.93) in the G+P group. 84 (94%) CDEA+G patients achieved the collection goal compared to 42 (68%) G+P patients (P<0.0001). Patients in the CDEA+G group required an average of 1.6 apheresis sessions to reach the target while patients in the G+P group required an average of 3 sessions (P<0.0001). Our data suggest that CDEA+G mobilizes stem cells significantly more effectively than G+P.
160 Comparing Cyclophosphamide with G-CSF and Plerixafor with G-CSF As Stem Cell Mobilization (SCM) Regimens for Multiple Myeloma (MM) Patients: An Evaluation of Mobilization Efficacy and Toxicity Carlyn Rose C. Tan 1, Philip A. Pancari 1, John Ulicny 2, Mary Ellen Martin 3, Stefan Klaus Barta 4, Patricia Lamont Kropf 5, Henry C. Fung 1. 1 Department of Hematology and Oncology, Fox Chase Cancer Center/Temple University Hospital, Philadelphia, PA; 2 Bone Marrow Transplant Program, Temple University Hospital, Philadephia, PA; 3 Bone Marrow Transplant Program, Temple University Hospital, Philadelphia, PA; 4 Department of Hematology and Oncology, Fox Chase Cancer Center, Philadelphia, PA; 5 Bone Marrow Transplant Program, Fox Chase Cancer Center/Temple University Hospital, Philadelphia, PA Background: The ideal regimen for SCM in MM remains controversial. Chemomobilization with a single dose of cyclophosphamide (CY) with G-CSF (G) remains the most commonly used regimen. However, recent studies suggest that plerixafor (P) with G may be superior or equally effective as CY/G in first line SCM. We compared the efficacy and toxicities associated with CY/G versus P/G in MM pts who had SCM at our institution. Methods: From 1/2012 e 5/2015, 80 pts underwent SCM using CY/G or P/G. CY (3 gm/m2) was given day 1 (D1) with G starting D2. Pts were evaluated for the start of apheresis on D12. With P/G, pts started G on D1, P (0.24 mg/kg/day) on D4, and apheresis on D5. Demographics, CD34+ cell yield on D1 of apheresis, total CD34+ cell yield, toxicities, and time to engraftment were analyzed. Time to neutrophil recovery was based on the CIBMTR definition. Time to plt recovery was the first day with plt count 20 x 109 cells/L deemed not attributable to recent transfusions. Results: Of the 80 pts, 35 had SCM with CY/G and 45 received P/G. All but 1 pt had ASCT with melphalan conditioning. The median CD34+ cell yield on D1 and median total yield were not significantly different between the 2 groups (Table 1). There was 1 poor mobilizer (< 2 x 106 cells/kg in 3 aphereses, PM) in the CY/G arm and none in the P/G arm. The number of good mobilizers ( 5 x 106 cells/kg in 2 days, GM) and rapid mobilizers ( 4 x 106 cells/kg on D1, RM) in both arms were comparable. Most pts in the CY/G (83%) and P/G (87%) arm completed SCM in 1 session. CY/G was associated with more severe neutropenia (86% vs 0%, P<0.001), hospitalization (11% vs 0%, P¼0.020), and delay in apheresis (14% vs 0%, P¼0.009). There were also more pts with febrile neutropenia (5% vs 0%) after CY/G. Mean time to neutrophil recovery was significantly shorter with CY/G than with P/G (10.8 vs 11.4, P¼0.005), but plt recovery was not significantly different (13.6 vs 15.0, P¼0.161). Conclusion: Our data indicate that CY/G and P/G result in robust SCM in most MM pts. Both regimens were comparable when evaluating efficacy and efficiency. However, P/G was
Table 1 SCM and apheresis results
D1 CD34+ cell yield, median Total CD34+ cell yield, median PM, N (%) GM, N (%) RM, N (%) Completed in 1 apheresis, N (%) Completed in 2 aphereses, N (%)
CY/G (n¼35)
P/G (n¼45)
P
10.96 10.96 1 (3) 32 (91) 32 (91) 29 (83) 5 (14)
8.65 8.70 0 (0) 42 (93) 40 (89)* 39 (87) 4 (9)
0.170 0.052 0.254 0.748 0.936 0.636 0.449
*1 pt did not have D1 data Table 2 Engraftment
Mean time to ANC recovery (days) Mean time to plt recovery (days)
CY/G
P/G
P
10.8 13.6
11.4 15.0
0.005 0.161
Table 3 Toxicity
Delay of planned apheresis D1, N (%) Severe neutropenia, N (%) Neutropenic fever, N (%) Hospitalization from SCM-related AEs, N (%)
CY/G (n¼35)
P/G (n¼45)
P
5 (14)
0 (0)
0.009
30 (86) 2 (5) 4 (11)
0 (0) 0 (0) 0 (0)
<0.001 0.104 0.020
better tolerated and had a more predictable course, specifically D1 of apheresis. Therefore, P/G may be considered as the preferred SCM regimen in MM.
161 Retrospective Analysis of Autologous Peripheral Blood Stem Cell Mobilization Using G-CSF Including Biosimilar Nobuhiro Tsukada 1, Masahiro Ikeda 1, Sumito Shingaki 1, Kanji Miyazaki 1, Sohsuke Meshitsuka 1, Yumiko Yoshiki 1, Yu Abe 1, Yuko Konoma 2, Seiko Iki 1, 2, Kenshi Suzuki 1. 1 Division of Hematology, Japanese Red Cross Medical Center, Tokyo, Japan; 2 Division of Blood Transfusion Services, Japanese Red Cross Medical Center, Tokyo, Japan Topic Significance & Study Purpose/Background/ Rationale: Although originator filgrastim and lenograstim have been used for mobilization of autologous peripheral blood stem cells (PBSCs), biosimilar granulocyte colony stimulating factor (G-CSF) has taking place since it had introduced to the market. This retrospective analysis was aimed for comparing the efficacy of three different G-CSF products in mobilization of PBSCs. Methods, Intervention, & Analysis: One hundred and seven mobilizations were performed at Japanese Red Cross Medical Center between 2012 and 2015. We evaluated 90 patients mobilized either with G-CSF alone or cyclophosphamide (CPA) + G-CSF. Sixty-three patients with multiple myeloma, 25 patients with light-chain amyloidosis, and two patients with POEMS syndrome were included. Median age at mobilization was 55 years (range 30-68) and 53 patients were male. Fifty-four patients were mobilized with G-CSF alone and other 36 patients were mobilized with CPA + G-CSF. In regards of the types of G-CSF, originator filgrastim (F) was used for 58 patients, lenograstim (L) was used for 20 patients, and biosimilar filgrastim (BS-F) was used for 12 patients. Successful mobilization was defined as obtaining 1.0 x 106/kg CD34-positive cells per patients body weight.
Abstracts / Biol Blood Marrow Transplant 22 (2016) S19eS481
Findings & Interpretation: Successful mobilizations were observed in 83 of 90 patients. Median CD34-positive cells were 3.35 (0.5-9.8) x 106/kg and 5.75 (0.5-19) x 106/kg with G-CSF alone and CPA + G-CSF, respectively. Successful mobilizations were observed in 52 of 54 patients even with G-CSF alone. The differences in the efficacy of mobilization were not observed between G-CSF products used. Successful mobilizations were observed in 11 of 12 patients who were mobilized with BS-F. High-dose melphalan and autologous stem-cell transplantation was performed in 58 of 90 patients, and there was no difference in engraftment by G-CSF products used for mobilization. Discussion & Implications: Successful mobilization can be done by G-CSF alone if patients are appropriately selected. Utilization of biosimilar G-CSF did not affect the efficacy of mobilization, although the number of patients is still small. Biosimilar G-CSF may be used for an increasing number of patients and also for healthy donors in the future and these analyses of the efficacy will be important.
162 Pilot Trial of Homebound Stem Cell Transplantation at Memorial Sloan Kettering Cancer Center Jill Marie Vanak 1, Christina Bello 2, Payal Dixit 3, Victoria Nguyen 3, Heather Landau 4, Sergio A. Giralt 4. 1 Ambulatory, Memorial Sloan-Kettering Cancer Center, New York, NY; 2 Memorial Sloan-Kettering Cancer Center, New York, NY; 3 Memorial Sloan Kettering Cancer Center, New York, NY; 4 Department of Medicine, Adult Bone Marrow Transplant Service, Memorial Sloan Kettering Cancer Center, New York, NY System-based barriers lead to the inability of individuals to access appropriate treatment and oncologic care. Establishment of a homebound hematopoietic stem cell transplantation (HSCT) program promotes increased access to care and decreased patient disparity. This research initiative seeks to expand care of a patient treated with HSCT into the home setting. The primary objective of the protocol is to assess the feasibility of performing all post-HSCT care for select patients with a diagnosis of multiple myeloma in New York City in the home environment. The program is considered feasible if no more than 10/15 patients are readmitted to the hospital within 21 days of transplantation. Secondary objectives include assessment of adverse events, patient and caregiver satisfaction, and accuracy of telemedicine. We report on the creation and establishment of a homebound HSCT program by a single academic medical center. This homebound program is the second within the US, and the first within an urban landscape. Recognition that analysis of early experiences can inform subsequent efforts by other institutions in developing like programs merits a comprehensive process review of the homebound initiative. Identification of infrastructure and research needs and the outline of an implementation framework with standard operating guidelines will assist in the introduction of similar programs within other institutions. Barriers to program establishment included limited evidence as to both the clinical and financial effectiveness of a homebound program, reimbursement issues with third-party payers, increased burden to providers within an institution not licensed as a home health agency, and legal counsel due to individual state regulations surrounding home care. As the majority of program establishment and implementation is completed in isolation, the need for an openly accessible knowledge base and structured collaboration surrounding sharing of best practices regarding the provision of oncologic care in the home environment is evident.
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163 A Higher Amount of More Primitive Stem Cells Is Mobilized By G-CSF Alone Compared to the Addition of Plerixafor: Autologous Blood Stem Cell Graft Composition Collected after Various Mobilization Methods Nina Worel 1, Gerhard Fritsch 2, Hermine Agis 3, Niklas Zojer 4, Reinhard Ruckser 5, Hildegard Greinix 6. 1 Transfusion Medicine, Medical University of Vienna, Vienna, Austria; 2 Childrens Cancer Researche Institute, Vienna, Austria; 3 Internal Medicine I, Oncology, Medical University of Vienna, Vienna, Austria; 4 Internal Medicine I, Wilhelminen Hospital, Vienna, Austria; 5 Internal Medicine II, Danube Hospital, Vienna, Austria; 6 Division of Hematology, Medical University of Graz, Vienna, Austria Introduction: Peripheral blood stem cells (PBSCs) are most commonly mobilized by the use of cytokines, alone or in combination with chemotherapy (C). In hard-to-mobilize patients, plerixafor (P) can enhance stem cell mobilization. However, limited data on graft content with regard to various mobilization methods are available. We aimed to assess the effects of different mobilization strategies on CD34 cell subclasses and lymphocyte subsets. Materials and Methods: A total of 81 PBSC grafts from patients with multiple myeloma (n¼52), malignant lymphoma (n¼23), and solid tumors (n¼6) mobilized with G-CSF alone (G; n¼20), C+G (CG; n¼21), G+P (GP; n¼22) or C+G+P (CGP; n¼18) were included in this study. Flow cytometric analyzes were performed by a LSRFortessaÔ cell analyzer (Becton Dickinson). An 11 colour single-platform method was used to define and enumerate CD34+subpopulations and lymphocytes. CD34, CD45, 7-Aminoactinomycin D (7-AAD) and scatter properties were used to define viable CD34+ cells which were further characterized by CD45RA, AC133, CD7, 10, 19, 3, 4, 8, 33, 38, and CD56. According to a recently published definition the earliest CD34+ cell fraction is represented by the multi potent progenitors (MPP) which are 45RA-CD133+CD38-CD10-. Cells acquiring CD45RA become lymphoid-primed MPP (LMPP) and turn into myeloid (late GMP), or multi-lymphoid progenitors (MLP). MPP that do not acquire CD45RA but down regulate CD133, become common erythro-myeloid progenitors (EMPs) differentiating into progenitors for megakaryocytes and erythrocytes, and for eosinophilic and basophilic granulocytes. Results: There was no significant difference in the amount of harvested CD34+ cells, and in the proportion of CD3+ and 4/8 ratio between the groups. Interestingly, the proportion of the most primitive stem cells (MPP) was significantly higher in the G group (55%) compared to all other groups (32, 36, 42, p<0.01). Chemomobilized patients collected a significantly higher proportion of LMPP whereas the proportion of late GMP was significantly higher in the P (GP+CGP) mobilized groups compared to G or CG, respectively. The proportion of MLP was the highest in the GP group compared to all other regimens. The amount of CD3+, CD4+, CD8+ and CD19+ lymphocytes was significantly higher in the GP group compared to chemomobilized groups (CGP+CG), whereas in the CG group a significant lower amount of NK cells was detected compared to G and GP mobilization. Conclusion: In contrast to previous findings where P is reported to mobilize more primitive stem cells, we found that mobilization by cytokine alone yielded the highest proportion of MPP. In addition, P augmentation leads to mobilization of more committed stem cells compared to G or CG. Whether these differences are associated with immune reconstitution, long-term engraftment or patient outcome needs to be evaluated in larger patient groups with longer follow-up.
Abstracts / Biol Blood Marrow Transplant 22 (2016) S19eS481
received G+P between January 2011 and September 2014. Baseline characteristics were similar between the two groups. The mean CD34+ yield for the CDEA+G group was 30.95 x106 cells/kg (range, 14.32-67.29) compared with 22.39 x106 cells/ kg (range, 4.83-42.93) in the G+P group. 84 (94%) CDEA+G patients achieved the collection goal compared to 42 (68%) G+P patients (P<0.0001). Patients in the CDEA+G group required an average of 1.6 apheresis sessions to reach the target while patients in the G+P group required an average of 3 sessions (P<0.0001). Our data suggest that CDEA+G mobilizes stem cells significantly more effectively than G+P.
160 Comparing Cyclophosphamide with G-CSF and Plerixafor with G-CSF As Stem Cell Mobilization (SCM) Regimens for Multiple Myeloma (MM) Patients: An Evaluation of Mobilization Efficacy and Toxicity Carlyn Rose C. Tan 1, Philip A. Pancari 1, John Ulicny 2, Mary Ellen Martin 3, Stefan Klaus Barta 4, Patricia Lamont Kropf 5, Henry C. Fung 1. 1 Department of Hematology and Oncology, Fox Chase Cancer Center/Temple University Hospital, Philadelphia, PA; 2 Bone Marrow Transplant Program, Temple University Hospital, Philadephia, PA; 3 Bone Marrow Transplant Program, Temple University Hospital, Philadelphia, PA; 4 Department of Hematology and Oncology, Fox Chase Cancer Center, Philadelphia, PA; 5 Bone Marrow Transplant Program, Fox Chase Cancer Center/Temple University Hospital, Philadelphia, PA Background: The ideal regimen for SCM in MM remains controversial. Chemomobilization with a single dose of cyclophosphamide (CY) with G-CSF (G) remains the most commonly used regimen. However, recent studies suggest that plerixafor (P) with G may be superior or equally effective as CY/G in first line SCM. We compared the efficacy and toxicities associated with CY/G versus P/G in MM pts who had SCM at our institution. Methods: From 1/2012 e 5/2015, 80 pts underwent SCM using CY/G or P/G. CY (3 gm/m2) was given day 1 (D1) with G starting D2. Pts were evaluated for the start of apheresis on D12. With P/G, pts started G on D1, P (0.24 mg/kg/day) on D4, and apheresis on D5. Demographics, CD34+ cell yield on D1 of apheresis, total CD34+ cell yield, toxicities, and time to engraftment were analyzed. Time to neutrophil recovery was based on the CIBMTR definition. Time to plt recovery was the first day with plt count 20 x 109 cells/L deemed not attributable to recent transfusions. Results: Of the 80 pts, 35 had SCM with CY/G and 45 received P/G. All but 1 pt had ASCT with melphalan conditioning. The median CD34+ cell yield on D1 and median total yield were not significantly different between the 2 groups (Table 1). There was 1 poor mobilizer (< 2 x 106 cells/kg in 3 aphereses, PM) in the CY/G arm and none in the P/G arm. The number of good mobilizers ( 5 x 106 cells/kg in 2 days, GM) and rapid mobilizers ( 4 x 106 cells/kg on D1, RM) in both arms were comparable. Most pts in the CY/G (83%) and P/G (87%) arm completed SCM in 1 session. CY/G was associated with more severe neutropenia (86% vs 0%, P<0.001), hospitalization (11% vs 0%, P¼0.020), and delay in apheresis (14% vs 0%, P¼0.009). There were also more pts with febrile neutropenia (5% vs 0%) after CY/G. Mean time to neutrophil recovery was significantly shorter with CY/G than with P/G (10.8 vs 11.4, P¼0.005), but plt recovery was not significantly different (13.6 vs 15.0, P¼0.161). Conclusion: Our data indicate that CY/G and P/G result in robust SCM in most MM pts. Both regimens were comparable when evaluating efficacy and efficiency. However, P/G was
Table 1 SCM and apheresis results
D1 CD34+ cell yield, median Total CD34+ cell yield, median PM, N (%) GM, N (%) RM, N (%) Completed in 1 apheresis, N (%) Completed in 2 aphereses, N (%)
CY/G (n¼35)
P/G (n¼45)
P
10.96 10.96 1 (3) 32 (91) 32 (91) 29 (83) 5 (14)
8.65 8.70 0 (0) 42 (93) 40 (89)* 39 (87) 4 (9)
0.170 0.052 0.254 0.748 0.936 0.636 0.449
*1 pt did not have D1 data Table 2 Engraftment
Mean time to ANC recovery (days) Mean time to plt recovery (days)
CY/G
P/G
P
10.8 13.6
11.4 15.0
0.005 0.161
Table 3 Toxicity
Delay of planned apheresis D1, N (%) Severe neutropenia, N (%) Neutropenic fever, N (%) Hospitalization from SCM-related AEs, N (%)
CY/G (n¼35)
P/G (n¼45)
P
5 (14)
0 (0)
0.009
30 (86) 2 (5) 4 (11)
0 (0) 0 (0) 0 (0)
<0.001 0.104 0.020
better tolerated and had a more predictable course, specifically D1 of apheresis. Therefore, P/G may be considered as the preferred SCM regimen in MM.
161 Retrospective Analysis of Autologous Peripheral Blood Stem Cell Mobilization Using G-CSF Including Biosimilar Nobuhiro Tsukada 1, Masahiro Ikeda 1, Sumito Shingaki 1, Kanji Miyazaki 1, Sohsuke Meshitsuka 1, Yumiko Yoshiki 1, Yu Abe 1, Yuko Konoma 2, Seiko Iki 1, 2, Kenshi Suzuki 1. 1 Division of Hematology, Japanese Red Cross Medical Center, Tokyo, Japan; 2 Division of Blood Transfusion Services, Japanese Red Cross Medical Center, Tokyo, Japan Topic Significance & Study Purpose/Background/ Rationale: Although originator filgrastim and lenograstim have been used for mobilization of autologous peripheral blood stem cells (PBSCs), biosimilar granulocyte colony stimulating factor (G-CSF) has taking place since it had introduced to the market. This retrospective analysis was aimed for comparing the efficacy of three different G-CSF products in mobilization of PBSCs. Methods, Intervention, & Analysis: One hundred and seven mobilizations were performed at Japanese Red Cross Medical Center between 2012 and 2015. We evaluated 90 patients mobilized either with G-CSF alone or cyclophosphamide (CPA) + G-CSF. Sixty-three patients with multiple myeloma, 25 patients with light-chain amyloidosis, and two patients with POEMS syndrome were included. Median age at mobilization was 55 years (range 30-68) and 53 patients were male. Fifty-four patients were mobilized with G-CSF alone and other 36 patients were mobilized with CPA + G-CSF. In regards of the types of G-CSF, originator filgrastim (F) was used for 58 patients, lenograstim (L) was used for 20 patients, and biosimilar filgrastim (BS-F) was used for 12 patients. Successful mobilization was defined as obtaining 1.0 x 106/kg CD34-positive cells per patients body weight.
Abstracts / Biol Blood Marrow Transplant 22 (2016) S19eS481
Findings & Interpretation: Successful mobilizations were observed in 83 of 90 patients. Median CD34-positive cells were 3.35 (0.5-9.8) x 106/kg and 5.75 (0.5-19) x 106/kg with G-CSF alone and CPA + G-CSF, respectively. Successful mobilizations were observed in 52 of 54 patients even with G-CSF alone. The differences in the efficacy of mobilization were not observed between G-CSF products used. Successful mobilizations were observed in 11 of 12 patients who were mobilized with BS-F. High-dose melphalan and autologous stem-cell transplantation was performed in 58 of 90 patients, and there was no difference in engraftment by G-CSF products used for mobilization. Discussion & Implications: Successful mobilization can be done by G-CSF alone if patients are appropriately selected. Utilization of biosimilar G-CSF did not affect the efficacy of mobilization, although the number of patients is still small. Biosimilar G-CSF may be used for an increasing number of patients and also for healthy donors in the future and these analyses of the efficacy will be important.
162 Pilot Trial of Homebound Stem Cell Transplantation at Memorial Sloan Kettering Cancer Center Jill Marie Vanak 1, Christina Bello 2, Payal Dixit 3, Victoria Nguyen 3, Heather Landau 4, Sergio A. Giralt 4. 1 Ambulatory, Memorial Sloan-Kettering Cancer Center, New York, NY; 2 Memorial Sloan-Kettering Cancer Center, New York, NY; 3 Memorial Sloan Kettering Cancer Center, New York, NY; 4 Department of Medicine, Adult Bone Marrow Transplant Service, Memorial Sloan Kettering Cancer Center, New York, NY System-based barriers lead to the inability of individuals to access appropriate treatment and oncologic care. Establishment of a homebound hematopoietic stem cell transplantation (HSCT) program promotes increased access to care and decreased patient disparity. This research initiative seeks to expand care of a patient treated with HSCT into the home setting. The primary objective of the protocol is to assess the feasibility of performing all post-HSCT care for select patients with a diagnosis of multiple myeloma in New York City in the home environment. The program is considered feasible if no more than 10/15 patients are readmitted to the hospital within 21 days of transplantation. Secondary objectives include assessment of adverse events, patient and caregiver satisfaction, and accuracy of telemedicine. We report on the creation and establishment of a homebound HSCT program by a single academic medical center. This homebound program is the second within the US, and the first within an urban landscape. Recognition that analysis of early experiences can inform subsequent efforts by other institutions in developing like programs merits a comprehensive process review of the homebound initiative. Identification of infrastructure and research needs and the outline of an implementation framework with standard operating guidelines will assist in the introduction of similar programs within other institutions. Barriers to program establishment included limited evidence as to both the clinical and financial effectiveness of a homebound program, reimbursement issues with third-party payers, increased burden to providers within an institution not licensed as a home health agency, and legal counsel due to individual state regulations surrounding home care. As the majority of program establishment and implementation is completed in isolation, the need for an openly accessible knowledge base and structured collaboration surrounding sharing of best practices regarding the provision of oncologic care in the home environment is evident.
S137
163 A Higher Amount of More Primitive Stem Cells Is Mobilized By G-CSF Alone Compared to the Addition of Plerixafor: Autologous Blood Stem Cell Graft Composition Collected after Various Mobilization Methods Nina Worel 1, Gerhard Fritsch 2, Hermine Agis 3, Niklas Zojer 4, Reinhard Ruckser 5, Hildegard Greinix 6. 1 Transfusion Medicine, Medical University of Vienna, Vienna, Austria; 2 Childrens Cancer Researche Institute, Vienna, Austria; 3 Internal Medicine I, Oncology, Medical University of Vienna, Vienna, Austria; 4 Internal Medicine I, Wilhelminen Hospital, Vienna, Austria; 5 Internal Medicine II, Danube Hospital, Vienna, Austria; 6 Division of Hematology, Medical University of Graz, Vienna, Austria Introduction: Peripheral blood stem cells (PBSCs) are most commonly mobilized by the use of cytokines, alone or in combination with chemotherapy (C). In hard-to-mobilize patients, plerixafor (P) can enhance stem cell mobilization. However, limited data on graft content with regard to various mobilization methods are available. We aimed to assess the effects of different mobilization strategies on CD34 cell subclasses and lymphocyte subsets. Materials and Methods: A total of 81 PBSC grafts from patients with multiple myeloma (n¼52), malignant lymphoma (n¼23), and solid tumors (n¼6) mobilized with G-CSF alone (G; n¼20), C+G (CG; n¼21), G+P (GP; n¼22) or C+G+P (CGP; n¼18) were included in this study. Flow cytometric analyzes were performed by a LSRFortessaÔ cell analyzer (Becton Dickinson). An 11 colour single-platform method was used to define and enumerate CD34+subpopulations and lymphocytes. CD34, CD45, 7-Aminoactinomycin D (7-AAD) and scatter properties were used to define viable CD34+ cells which were further characterized by CD45RA, AC133, CD7, 10, 19, 3, 4, 8, 33, 38, and CD56. According to a recently published definition the earliest CD34+ cell fraction is represented by the multi potent progenitors (MPP) which are 45RA-CD133+CD38-CD10-. Cells acquiring CD45RA become lymphoid-primed MPP (LMPP) and turn into myeloid (late GMP), or multi-lymphoid progenitors (MLP). MPP that do not acquire CD45RA but down regulate CD133, become common erythro-myeloid progenitors (EMPs) differentiating into progenitors for megakaryocytes and erythrocytes, and for eosinophilic and basophilic granulocytes. Results: There was no significant difference in the amount of harvested CD34+ cells, and in the proportion of CD3+ and 4/8 ratio between the groups. Interestingly, the proportion of the most primitive stem cells (MPP) was significantly higher in the G group (55%) compared to all other groups (32, 36, 42, p<0.01). Chemomobilized patients collected a significantly higher proportion of LMPP whereas the proportion of late GMP was significantly higher in the P (GP+CGP) mobilized groups compared to G or CG, respectively. The proportion of MLP was the highest in the GP group compared to all other regimens. The amount of CD3+, CD4+, CD8+ and CD19+ lymphocytes was significantly higher in the GP group compared to chemomobilized groups (CGP+CG), whereas in the CG group a significant lower amount of NK cells was detected compared to G and GP mobilization. Conclusion: In contrast to previous findings where P is reported to mobilize more primitive stem cells, we found that mobilization by cytokine alone yielded the highest proportion of MPP. In addition, P augmentation leads to mobilization of more committed stem cells compared to G or CG. Whether these differences are associated with immune reconstitution, long-term engraftment or patient outcome needs to be evaluated in larger patient groups with longer follow-up.