Impact of plerixafor use in the mobilization of blood grafts for autologous hematopoietic cell transplantation.

Plerixafor (PLER), a reversible antagonist of the CXC chemokine receptor type 4, has been in clinical use for mobilization of blood grafts for autologous hematopoietic cell transplantation (AHCT) for about 15 years. Initially PLER was investigated in placebo-controlled trials with the granulocyte colony-stimulating factor (G-CSF) filgrastim. It has also been used in combination with chemotherapy plus G-CSF in patients who had failed a previous mobilization attempt or appeared to mobilize poorly with current mobilization (preemptive use). This review summarizes what is known regarding addition of PLER to standard mobilization regimens. PLER increases mobilization of CD34+ cells, decreases the number of apheresis sessions needed to achieve collection targets and increases the proportion of patients who can proceed to AHCT. It appears also to increase the amount of various lymphocyte subsets in the grafts collected. In general, hematologic recovery after AHCT has been comparable to patients mobilized without PLER, although slower platelet recovery has been observed in some studies of patients who mobilize poorly. In phase III studies, long-term outcome has been comparable to patients mobilized without PLER. This also appears to be the case in patients receiving plerixafor for poor or suboptimal mobilization of CD34+ cells. In practice, PLER is safe and has not been shown to increase tumor cell mobilization.

Impact of the number of cryopreserved CD34+ cells in the infused blood grafts on hematologic recovery and survival in myeloma patients after autologous stem cell transplantation: Experience from the GOA study.

BACKGROUND: Prospective data on the impact of CD34+ cell loss during cryopreservation and the amount of cryopreserved CD34+ cells infused after high-dose therapy on hematologic recovery and post-transplant outcome in multiple myeloma (MM) are scarce. PATIENTS AND METHODS: This post-hoc study aimed to investigate factors associating with CD34+ cell loss during cryopreservation and the effects of the infusion of a very low number (<1.0 × 106 /kg, group A), low number (1-1.9 × 106 /kg, group B), and optimal number (≥2 × 106 /kg, group C) of thawed viable CD34+ cells on hematologic recovery, progression free survival, and overall survival after autologous stem cell transplantation among 127 patients with MM. RESULTS: In group C, pegfilgrastim use (P = 0.001), plerixafor use (P = 0.039), and older age ≥ 60 years (P = 0.026) were associated with less loss of CD34+ cells during cryopreservation. Better mobilization efficacy correlated with greater CD34+ cell loss in group B (P = 0.013 and P = 0.001) and in group C (P < 0.001 and P < 0.001). Early platelet engraftment was slowest in group A (20 d vs 12 d in group B vs 11 d in group C, P = 0.003). The infused viable CD34+ cell count <1.0 × 106 /kg seemed not to have influence on PFS (P = 0.322) or OS (P = 0.378) in MM patients. CONCLUSIONS: Cryopreservation impacts significantly on the CD34+ cell loss. A very low number of graft viable CD34+ cells did not affect PFS or OS.

Mobilization Strategies in Myeloma Patients Intended for Autologous Hematopoietic Cell Transplantation.

Background: Multiple myeloma is currently the leading indication for autologous hematopoietic cell transplantation (AHCT). A prerequisite for AHCT is mobilization and collection of adequate blood graft to support high-dose therapy. Current mobilization strategies include granulocyte colony-stimulating factor (G-CSF) alone or in combination with chemotherapy most commonly cyclophosphamide (CY). More recently, plerixafor has become into agenda especially in patients who mobilize poorly. In the selection of a mobilization method, several factors should be considered. Summary: Preplanned collection target is important as G-CSF plus plerixafor is more effective in the mobilization of CD34+ cells than G-CSF alone. On the other hand, CY plus G-CSF is superior to G-CSF only mobilization. Previous therapy and age of the patients are important considerations as G-CSF alone may not be effective enough in patients with risk factors for poor mobilization. These factors include extensive lenalidomide exposure, irradiation to bone marrow-bearing sites, higher age, or a previous mobilization failure. Also, local preferences and experiences as well as the number of apheresis needed are important issues as well as cost-effectiveness considerations. Mobilization method used may have implication for cellular composition of collected grafts, which might have an impact on posttransplant events such as hematologic and immune recovery in addition to also potential long-term outcomes. Key Message: Currently, G-CSF alone and preemptive plerixafor if needed might be considered as a standard mobilization strategy in MM patients intended for AHCT.

CD34+ Cell Mobilization, Autograft Cellular Composition and Outcome in Mantle Cell Lymphoma Patients.

Backgound: Autologous stem cell transplantation (ASCT) is a standard treatment in transplant-eligible mantle cell lymphoma (MCL) patients after first-line chemoimmunotherapy. Study Design and Methods: This prospective multicenter study evaluated the impact of CD34+ cell mobilization and graft cellular composition analyzed by flow cytometry on hematologic recovery and outcome in 42 MCL patients. Results: During CD34+ cell mobilization, a higher blood CD34+ cell count (>30 × 106/L) was associated with improved overall survival (median not reached [NR] vs. 57 months, p = 0.04). The use of plerixafor did not impact outcome. Higher number of viable cryopreserved graft CD34+ cells (>3.0 × 106/kg) was associated with faster platelet (median 11 vs. 15 days, p = 0.03) and neutrophil (median 9 vs. 10 days, p = 0.02) recovery posttransplant. Very low graft CD3+CD8+ cell count (≤10 × 106/kg) correlated with worse progression-free survival (PFS) (HR 4.136, 95% CI 1.547-11.059, p = 0.005). On the other hand, higher absolute lymphocyte count >2.5 × 109/L at 30 days after ASCT (ALC-30) was linked with better PFS (median NR vs. 99 months, p = 0.045) and overall survival (median NR in either group, p = 0.05). Conclusions: Better mobilization capacity and higher graft CD3+CD8+ cell count had a positive prognostic impact in this study, in addition to earlier lymphocyte recovery (ALC-30>2.5 × 106/L). These results need to be validated in another study with a larger patient cohort.

Mobilization characteristics, blood graft composition, and outcome in diffuse large B-cell lymphoma after autologous stem cell transplantation: Results from the prospective multicenter GOA study.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is a common indication for autologous stem cell transplantation (auto-SCT). STUDY DESIGN AND METHODS: This prospective noninterventional study aimed to evaluate the impact of mobilization characteristics and graft cellular content on hematologic recovery and outcome after auto-SCT among 68 patients with DLBCL. RESULTS: Better mobilization capacity as manifested by blood CD34+ cell count >32 × 106 /L and CD34+ cell yield of the first apheresis >2.75 × 106 /kg correlated with faster neutrophil (P = .005 and P = .017) and platelet (P = .002 and P < .001) recovery. A higher number of infused CD34+ cells (> 2.65 × 106 /kg) was associated with better 5-year overall survival (OS; 95% vs 67%, P = .012). The graft CD34+ CD133+ CD38- cell count >0.07 × 106 /kg was predictive of better 5-year OS (87% vs 63%; P = .008) and higher graft CD3+ cell count (>23.1 × 106 /kg) correlated also with better 5-year OS (80% vs 40%, P = .008). In multivariate analysis only disease status of CR I at auto-SCT was associated with better progression-free survival (P = .014) and OS (P = .039). CONCLUSION: The mobilization capacity of CD34+ cells impacted on early hematologic recovery in patients with DLBCL after auto-SCT. Higher graft CD34+ cell count and both CD34+ CD133+ CD38- and CD3+ cells were also associated with better OS. The effect of optimal graft cellular composition on outcome in DLBCL should be evaluated in a randomized study.

Autograft cellular composition and outcome in myeloma patients: Results of the prospective multicenter GOA study.

BACKGROUND: Autologous stem cell transplantation (auto-SCT) is a widely used treatment option in multiple myeloma (MM) patients. The optimal graft cellular composition is not known. STUDY DESIGN AND METHODS: Autograft cellular composition was analyzed after freezing by flow cytometry in 127 MM patients participating in a prospective multicenter study. The impact of graft cellular composition on hematologic recovery and outcome after auto-SCT was evaluated. RESULTS: A higher graft CD34+ cell content predicted faster platelet recovery after auto-SCT in both the short and long term. In patients with standard-risk cytogenetics, a higher graft CD34+ count (>2.5 × 106 /kg) was linked with shorter progression-free survival (PFS; 28 vs. 46 months, p = 0.04), but there was no difference in overall survival (OS) (p = 0.53). In a multivariate model, a higher graft CD34+ CD133+ CD38- (>0.065 × 106 /kg, p = 0.009) and NK cell count (>2.5 × 106 /kg, p = 0.026), lenalidomide maintenance and standard-risk cytogenetics predicted better PFS. In contrast, a higher CD34+ count (>2.5 × 106 /kg, p = 0.015) predicted worse PFS. A very low CD3+ cell count (≤20 × 106 /kg, p = 0.001) in the infused graft and high-risk cytogenetics remained predictive of worse OS. CONCLUSIONS: Autograft cellular composition may impact outcome in MM patients after auto-SCT. More studies are needed to define optimal graft composition.

CD34+ cell mobilization, blood graft composition, and posttransplant recovery in myeloma patients compared to non-Hodgkin's lymphoma patients: results of the prospective multicenter GOA study.

BACKGROUND: Autologous stem cell transplantation is an established treatment option for patients with multiple myeloma (MM) or non-Hodgkin's lymphoma (NHL). STUDY DESIGN AND METHODS: In this prospective multicenter study, 147 patients with MM were compared with 136 patients with NHL regarding the mobilization and apheresis of blood CD34+ cells, cellular composition of infused blood grafts, posttransplant recovery, and outcome. RESULTS: Multiple myeloma patients mobilized CD34+ cells more effectively (6.3 × 106 /kg vs. 3.9 × 106 /kg, p = 0.001). The proportion of poor mobilizers (peak blood CD34+ cell count <20 × 106 /L) was higher in NHL patients (15% vs. 3%, p < 0.001). Plerixafor was added to rescue the mobilization failure in 17 MM patients (12%) and in 35 NHL patients (26%; p = 0.002). The infused grafts contained more natural killer (NK) and CD19+ cells in MM patients. Blood platelet and NK-cell counts were higher in MM patients posttransplant. Early treatment-related mortality was low in both groups, but NHL patients had a higher late (>100 days) nonrelapse mortality (NRM; 6% vs. 0%, p = 0.003). CONCLUSIONS: Non-Hodgkin's lymphoma and MM patients differ in terms of mobilization of CD34+ cells, graft cellular composition, and posttransplant recovery. Thus, the optimal graft characteristics may also be different.

A prospective comparison of pegfilgrastim and lipegfilgrastim combined with chemotherapy in the mobilization of CD34+ cells in NHL patients.

BACKGROUND: Autologous stem cell transplantation (auto-SCT) is a treatment approach in non-Hodgkin lymphoma (NHL) patients. The options for mobilization of CD34+ cells to support high-dose therapy are granulocyte-colony stimulating factors (G-CSFs) alone or after chemotherapy. Limited data exist on the efficacy of lipegfilgrastim (LIPEG) in the mobilization field. PATIENTS AND METHODS: The present prospective nonrandomized study compared LIPEG 6 mg (n = 40) with pegfilgrastim (PEG) 6 mg (n = 37) in the mobilization of blood CD34+ cells after chemotherapy in NHL patients with comparable mobilizing chemotherapy and disease status before auto-SCT. RESULTS: Significantly higher blood CD34+ cell (B-CD34+ ) counts were observed in the LIPEG group at the start of the first apheresis (44 vs 23 × 106 /L, P = .009), in line with a higher collection yield of the first apheresis (3.3 vs 2.1 × 106 /kg, P = .086) and total yield of CD34+ cells (4.7 vs 2.9 × 106 /kg, P = .004). LIPEG proved to be a more effective G-CSF, resulting in a higher B-CD34+ cell peak (60 vs 32 × 106 /L, P = .030) and higher proportion of excellent mobilizers (33% vs 8%, P = .008). The superiority of LIPEG was confirmed in the multivarite analysis concerning the CD34+ cell yield of the first apheresis day (P = .010) and the total yield (P = .001). CONCLUSION: The mobilization of blood grafts with LIPEG added to chemotherapy was associated with higher CD34+ cell apheresis yields than with PEG. A randomized study is warranted to verify these findings.

Impact of lenalidomide-based induction therapy on the mobilization of CD34+ cells, blood graft cellular composition, and post-transplant recovery in myeloma patients: a prospective multicenter study.

BACKGROUND: Lenalidomide is an immunomodulatory drug that is also currently used in transplant-eligible patients with multiple myeloma. Previous studies have suggested a negative impact of lenalidomide on the mobilization of CD34+ cells. No data are available regarding the more detailed composition of blood grafts after lenalidomide. STUDY DESIGN AND METHODS: In a multicenter, prospective study, we analyzed the mobilization of CD34+ cells, graft cellular composition, and post-transplant hematologic recovery in 26 patients with multiple myeloma after lenalidomide-based induction and in 34 lenalidomide-naive controls with multiple myeloma. All patients were mobilized with low-dose cyclophosphamide plus granulocyte-colony-stimulating factor. The cellular composition of the grafts was analyzed from thawed, cryopreserved samples with flow cytometry. Graft function was evaluated by engraftment data and by complete blood counts until 12 months after the graft infusion. RESULTS: Patients in the lenalidomide arm had lower median peak CD34+ counts and approximately 40% lower CD34+ cell yields from the first apheresis session, but these differences were not significant. The median total number of CD34+ cells collected was comparable (6.4 vs. 7.5 × 106 /kg). The number of apheresis sessions was higher in the lenalidomide group (2 vs. 1; p = 0.039). The blood graft composition was comparable between the groups. Hematologic recovery within 12 months post-transplant did not differ between the groups. CONCLUSION: Lenalidomide-based induction seems to have an impact on the number of aphereses performed, but not on the total yields of the CD34+ cells in the graft. Neither cellular composition of the grafts nor post-transplant recovery was affected by the limited pre-transplant exposure to lenalidomide.

Blood graft cellular composition and posttransplant outcomes in myeloma patients mobilized with or without low-dose cyclophosphamide: a randomized comparison.

BACKGROUND: Autologous stem cell transplantation is a standard treatment in multiple myeloma (MM). Blood grafts are usually collected after mobilization with granulocyte-colony-stimulating factor (G-CSF) alone or in a combination with cyclophosphamide (CY). There is limited knowledge of the possible effects of different mobilization regimens on blood graft characteristics and posttransplant outcomes. STUDY DESIGN AND METHODS: Thirty-eight patients with MM were included in this study. The patients were randomly assigned at registration to mobilization with either low-dose CY plus G-CSF (Arm A) or G-CSF alone (Arm B) and received three cycles of lenalidomide, bortetzomib, and dexamethasone induction. Flow cytometry analysis of lymphocyte subsets in the blood grafts after cryopreservation was performed. Hematologic and immune recovery were evaluated up to 12 months posttransplant. RESULTS: The blood grafts in Arm A contained significantly more CD34+ cells but in Arm B there was a greater proportion of CD34+CD38- cells and higher numbers of T and B lymphocytes as well as natural killer (NK) cells. The engraftment was comparable but lymphocyte count at 15 days posttransplant was higher in Arm B (0.8 × 10(9) /L vs. 0.5 × 10(9) /L, p = 0.033). At 3 and 6 months posttransplant the total number of NK cells was also higher in G-CSF-mobilized patients. There was no difference in progression-free survival between the study arms. CONCLUSION: CY plus G-GSF yields more CD34+ cells but seems to diminish lymphocyte and NK cell counts in the grafts and hampers immune recovery after transplantation. Thus G-CSF alone might be a preferred mobilization method due to more rapid immune recovery posttransplant.

Cost analysis of a randomized stem cell mobilization study in multiple myeloma.

Upfront autologous stem cell transplantation (ASCT) is the standard therapy for younger multiple myeloma (MM) patients. MM patients usually undergo stem cell mobilization with cyclophosphamide (CY) followed by granulocyte colony-stimulating factor (G-CSF), or with G-CSF alone. A limited number of randomized studies are available comparing costs of different mobilization strategies. Eighty transplant-eligible patients aged up to 70 years with untreated MM were included in this prospective study. The patients were treated with RVD induction for three 21-day cycles and randomized 1:1 at inclusion into one of the two mobilization arms CY 2 g/m(2) + G-CSF [arm A] vs. G-CSF alone [arm B]. Plerixafor was given according to a specific algorithm if needed. Sixty-nine patients who received mobilization followed by blood graft collection were included in the cost analysis. The median total costs of the mobilization phase were significantly higher in arm A than in arm B (3855 € vs. 772 €, p ≤ 0.001). The cumulative median cost of the mobilization and collection phases was significantly lower in arm B than in arm A (8524 € vs. 11,622 €, p = 0.012). There was no significant difference between the arms in the total median costs of ASCT (n = 59) (34,997 € in arm A vs. 31,981 € in arm B, p = 0.118). Mobilization with G-CSF alone seems to be a preferable mobilization method for MM patients in terms of mobilization and apheresis costs. In addition, it requires less hospital resource utilization.

Blood graft cellular composition and posttransplant recovery in non-Hodgkin's lymphoma patients mobilized with or without plerixafor: a prospective comparison.

BACKGROUND: Autologous stem cell transplantation is commonly used to treat non-Hodgkin's lymphomas (NHLs). Cellular composition of the blood grafts apparently has a role in the posttransplant hematologic and immune recovery. Plerixafor increases the mobilization of CD34+ cells and higher amounts of various lymphocyte subsets have been reported in the grafts. Limited prospective data are available in regard to graft cellular composition, hematologic and immune recovery, and patient outcomes in NHL patients who receive plerixafor added to chemomobilization. STUDY DESIGN AND METHODS: Forty-one patients with NHL participated in this prospective study. All patients received chemomobilization and 15 poor mobilizers also received plerixafor. CD34+ cell subsets and lymphocyte subsets of cell grafts, posttransplant hematologic and immune recovery, and outcome were evaluated. RESULTS: Blood grafts in the plerixafor group contained a significantly higher proportion of CD34+133+CD38- cells and more lymphocytes of all major subsets except B lymphocytes. Neutrophil engraftment was comparable and platelet recovery slightly slower in the plerixafor group. Natural killer cell recovery was significantly faster in patients mobilized with plerixafor. Otherwise hematologic and immune recovery as well as short-time outcome were comparable even though there was a trend for progression-free survival and overall survival benefit in the plerixafor group. CONCLUSIONS: In poorly mobilizing NHL patients, plerixafor added to chemomobilization is safe and effective. It also modifies the blood graft composition in many ways, some of which have been linked to better outcomes in previous studies. Larger sets of patients and longer follow-up are needed to see whether plerixafor-mobilized grafts are associated with superior outcome of the patients.

Engraftment and outcome after autologous stem cell transplantation in plerixafor-mobilized non-Hodgkin's lymphoma patients.

BACKGROUND: Plerixafor is used in combination with granulocyte-colony-stimulating factor to enhance the mobilization of hematopoietic stem cells. Limited data are available in regard to effects of plerixafor on posttransplant outcomes in chemomobilized patients who appear to mobilize poorly. STUDY DESIGN AND METHODS: Eighty-nine chemomobilized patients with non-Hodgkin's lymphoma (NHL) were included in this retrospective study. Thirty-three patients had received plerixafor preemptively (plerixafor group) and 56 patients served as controls. Posttransplantation outcomes including infections, hematologic recovery, and relapse were recorded. RESULTS: The median fold increase of CD34+ cells after the first plerixafor dose was 4.1 in patients mobilized with chemotherapy plus filgrastim and 7.2 in those mobilized with chemotherapy plus pegfilgrastim (p = 0.027). The median number of collected CD34+ cells was 3.5 × 10(6) CD34+ cells/kg in the plerixafor group and 4.2 × 10(6) CD34+ cells/kg in the control group (p = 0.076). Early engraftment was comparable between the groups (10 days for neutrophils >0.5 × 10(9) /L and 14 days for platelets >20 × 10(9) /L, respectively). Also late engraftment within 12 months was comparable except higher hemoglobin level at 3 months in the control group (121 g/L vs. 112 g/L, p = 0.009). Progression-free survival at 1 year after autologous stem cell transplantation (ASCT) was 79% in the plerixafor group and 86% in the control group (p = 0.399). CONCLUSIONS: Long-term engraftment and outcome after ASCT seem to be comparable in NHL patients receiving plerixafor compared to chemomobilized patients. These observations support the use of plerixafor in patients who mobilize poorly.

CD34+ cell subclasses and lymphocyte subsets in blood grafts collected after various mobilization methods in myeloma patients.

BACKGROUND: Cyclophosphamide (CY) combined with granulocyte-colony-stimulating factor (G-CSF) is commonly used to mobilize stem cells in multiple myeloma (MM). Plerixafor may also be used with G-CSF in patients who mobilize poorly or it may be added to chemomobilization to boost mobilization. Limited data are available on graft content collected after various mobilization methods. STUDY DESIGN AND METHODS: Blood grafts collected from 21 MM patients were retrospectively analyzed. We analyzed CD34+ subclasses and lymphocyte subsets from cryopreserved grafts collected on the next morning after plerixafor injection in nine MM patients mobilized with G-CSF with (n = 5) or without preceding CY (n = 4). As controls we had the first collections from 12 MM patients mobilized with low-dose CY with G-CSF. RESULTS: The proportion of the most primitive stem cells (CD34+CD133+CD38-) from all CD34+ cells in the graft was higher in the plerixafor-treated patients but there was no significant difference in the total number of these cells. The numbers of CD19+ B lymphocytes and natural killer cells were higher in patients collected after G-CSF plus plerixafor when compared to the patients mobilized with CY plus G-CSF. Early engraftment after high-dose melphalan was comparable between the groups. CONCLUSION: Plerixafor appears to have effects on blood stem cell graft composition in myeloma patients. A higher number of grafts should be evaluated in regard to cellular content and longer follow-up of the patients is needed to evaluate the potential clinical impact of graft content.

Loss of CD34+ Cells and Effect of the Number of Viable Cryopreserved CD34+ Cells in the Infused Blood Grafts on Hematologic Recovery, Progression-Free Survival and Overall Survival in NHL Patients After Autologous Stem Cell Transplantation.

PATIENTS: This post-hoc study aimed to find out factors affecting graft viable CD34+ cell loss during processing and cryopreservation in 129 non-Hodgkin lymphoma (NHL) patients receiving autologous stem cell transplantation (auto-SCT) and the impact of a low (< 2.0 × 106/kg, group A) and a decent number (≥ 2 × 106/kg, group B) of viable CD34+ cells infused on the hematologic recovery, progression-free survival (PFS) and overall survival (OS) after auto-SCT. RESULTS: The median loss of viable CD34+ cells during cryopreservation was higher in group A (47% vs. 19%, p < .001). A higher yield of CD34+ cells at the first apheresis in group B (p = .002) was linked with greater loss of viable graft CD34+ cells after cryopreservation. Filgrastim (FIL) use for mobilization seemed to associate with higher viable CD34+ cell loss compared to pegfilgrastim (PEG) or lipegfilgrastim (LIPEG) in both groups (in group A FIL 66 vs. PEG 35%, p = .006; in group B FIL 37 vs. PEG 15 vs. LIPEG 13%, p < .001). Hematologic recovery after auto-SCT was faster in group B. Neither viable CD34+ cell loss during storage nor viable CD34+ cell number < 2.0 × 106/kg infused affected on PFS or OS. CONCLUSIONS: G-CSF type used in mobilization and mobilization capacity were found to correlate with viable CD34+ cell loss during processing and storage. Most importantly, low infused viable CD34+ cell count did not seem to impact on PFS or OS.

Blood graft lymphocyte subsets after plerixafor injection in non-Hodgkin's lymphoma patients mobilizing poorly with chemotherapy plus granulocyte-colony-stimulating factor.

BACKGROUND: A combination of chemotherapy plus granulocyte-colony-stimulating factor (G-CSF) (chemomobilization) is commonly used to mobilize CD34+ cells to circulation. Plerixafor, a chemokine CXCR4 antagonist, increases the mobilization of CD34+ cells and may also have effect on graft composition. STUDY DESIGN AND METHODS: We have analyzed lymphocyte subsets in grafts collected on the next morning after plerixafor injection in 13 chemomobilized patients with non-Hodgkin's lymphoma (NHL) mobilizing poorly. As controls we had the first leukapheresis products from 11 NHL patients mobilized with chemotherapy plus G-CSF. The analyses were performed from cryopreserved apheresis products. RESULTS: The median counts of both total CD3+ T cells and natural killer (NK) cells (CD3-CD16/56+) in the graft were significantly higher in plerixafor-treated group compared to the control group. Both helper T-lymphocytes (CD3+CD4+) and suppressor T-lymphocytes (CD3+CD8+) were significantly increased in the plerixafor-treated group so that CD4+/CD8+ ratio in the graft did not differ between the groups. CD19+ cells were evident only at very small amounts in few patients in both groups, and the CD34+ cell content of the graft did not differ between the groups. Engraftment after high-dose therapy was comparable between the groups. CONCLUSION: Plerixafor added to chemomobilization in poor mobilizers seems to mobilize more T cells and NK cells than chemomobilization. Larger patient numbers and longer follow-up is needed in regard to evaluate posttransplant complications and risk of relapse in patients receiving plerixafor due to poor mobilization.

Blood graft composition after plerixafor injection in patients with NHL.

BACKGROUND: Plerixafor is used to mobilize CD34(+) hematopoietic stem cells from bone marrow to circulation. Limited data are available in regard to graft cellular content collected after plerixafor. OBJECTIVES: The aim of this study was to assess effects of plerixafor added to chemomobilization on graft CD34(+) cell subclasses, lymphocyte subsets, engraftment, and post-transplant course in non-Hodgkin lymphoma (NHL) patients. METHODS: Thirty-four patients with NHL were included. All patients received chemotherapy plus G-CSF to mobilize stem cells. Nineteen patients received plerixafor pre-emptively owing to poor mobilization or poor collection yields. The rest of the patients constituted the control group. Flow cytometric analyzes were performed from cryopreserved graft samples. Also, data on post-transplant engraftment and outcome were collected. RESULTS: The proportion of primitive stem cells (CD34(+)  CD133(+)  CD38(-) ) was significantly higher after the plerixafor injection when compared to the first collection in the control group. The amount of T cells (CD3(+) ), helper (CD3(+)  CD4(+) ) T subsets, and suppressor (CD3(+)  CD8(+) ) T subsets in the graft was all significantly higher in the plerixafor group. Also, the amount of NK cells (CD3(-)  CD16/56(+) ) was higher. Engraftment after high-dose therapy was comparable between the groups, but leukocyte and platelet count at 6 months were higher in patients receiving plerixafor-mobilized grafts. CONCLUSION: Plerixafor, when used pre-emptively in addition to chemomobilization, seems to mobilize more primitive CD34(+) stem cells, T lymphocytes, and NK cells. Whether these differences are associated with immune reconstitution, long-term engraftment, or patient outcomes needs to be evaluated in larger patient groups with longer follow-up.

Blood Graft and Outcome After Autologous Stem Cell Transplantation in Patients With Primary Central Nervous System Lymphoma.

BACKGROUND: Autologous stem cell transplantation (auto-SCT) is a treatment option for patients with primary central nervous system lymphoma (PCNSL). METHODS: In this prospective multicenter study, the effects of blood graft cellular content on hematologic recovery and outcome were analyzed in 17 PCNSL patients receiving auto-SCT upfront. RESULTS: The infused viable CD34+ cell count > 1.7 × 106/kg correlated with more rapid platelet engraftment (10 vs. 31 days, P = 0.027) and with early neutrophil recovery (day + 15) (5.4 vs. 1.6 × 109/L, P = 0.047). A higher number of total collected CD34+ cells > 3.3 × 106/kg infused predicted worse 5-year progression-free survival (PFS) (33% vs. 100%, P = 0.028). In addition, CD3+CD8+ T cells > 78 × 106/kg in the infused graft impacted negatively on the 5-year PFS (0% vs. 88%, P = 0.016). CONCLUSION: The cellular composition of infused graft seems to impact on the hematologic recovery and PFS post-transplant. Further studies are needed to verify the optimal autograft cellular content in PCNSL.

Autograft cellular composition and outcome in NHL patients: results of the prospective multicenter GOA study.

Autologous stem cell transplantation (auto-SCT) is an established treatment option in patients with non-Hodgkin lymphoma (NHL). In this prospective multicenter study, the effect of infused blood graft cellular composition on post-transplant outcome was analyzed in 129 NHL patients. Higher graft CD34+ cell content (>2.5 × 106/kg) correlated with better progression-free survival (PFS) (p=.009) and overall survival (OS) (p=.004). Higher graft CD34+CD133+CD38- counts (>0.08 × 106/kg) were also linked with better PFS (p=.03) and OS (p=.004), and these survival benefits retained in multivariate analyses. Higher infused CD3+CD4+ cell count (>37 × 106/kg) predicted better PFS (p=.013) and OS (p=.007) in multivariate analysis. Autograft cellular composition seems to impact outcome in NHL patients. These observations regarding composition of optimal graft in autologous setting should be validated in an independent patient series or in a randomized study.