Cyclophosphamide mobilization does not improve outcome in patients receiving stem cell transplantation for multiple myeloma

Mobilization strategies with and without plerixafor for autologous stem cell transplant in patients with multiple myeloma

Autologous stem cell transplantation is a standard treatment strategy for patients with multiple myeloma that requires effective mobilization and apheresis of peripheral blood progenitor cells; however, in the current era of novel myeloma induction therapies, the optimal mobilization regimen to enhance stem cell yield while limiting toxicity and resource utilization remains unknown. In this multicenter retrospective study, we assessed apheresis and transplant outcomes in myeloma patients mobilized with granulocyte colony stimulating factor (G-CSF) alone (n = 62), G-CSF with chemotherapy (n = 43), or G-CSF with the CXCR4 antagonist plerixafor (n = 417). Compared to patients treated with G-CSF alone, the plerixafor group required significantly fewer median apheresis sessions (1 vs 2, p = 0.0023) with higher CD34+ stem cell yield (9.9 vs 5.8 × 106 cells/kg, p < 0.001) and had significantly faster engraftment of neutrophils (HR 1.54, 95% CI 1.17-2.03) and platelets (HR 2.24, 95% CI 1.69-2.96) after transplant. Additionally, the plerixafor group showed a significantly better toxicity profile and lower adverse event rate than patients treated with G-CSF alone (p = 0.0028) or chemomobilization (p < 0.0001), with a trend toward reduced survival in chemomobilization patients. Taken together, these data support the routine use of plerixafor-based mobilization to increase apheresis efficiency and reduce toxicity in myeloma patients undergoing transplant.

Optimizing Autologous Stem Cell Transplantation in Multiple Myeloma: The Impact of Intensive Chemomobilization

Most transplant-eligible multiple myeloma (MM) patients undergo autologous peripheral blood stem cell collection (PBSC) using G-CSF with on-demand plerixafor (G ± P). Chemomobilization (CM) can be used as a salvage regimen after G ± P failure or for debulking residual tumor burden ahead of autologous peripheral blood stem cell transplantation (ASCT). Prior studies utilizing cyclophosphamide-based CM have not shown long-term benefits. At our center, intensive CM (ICM) using a PACE- or HyperCVAD-based regimen has been used to mitigate "excessive" residual disease based on plasma cell (PC) burden or MM-related biomarkers. Given the lack of efficacy of non-ICM, we sought to determine the impact of ICM on event-free survival (EFS), defined as death, progressive disease, or unplanned treatment escalation. We performed a retrospective study of newly diagnosed MM patients who collected autologous PBSCs with the intent to proceed immediately to ASCT at our center between 7/2020 and 2/2023. Patients were excluded if they underwent a tandem autologous or sequential autologous-allogeneic transplant, had primary PC leukemia, received non-ICM treatment (i.e., cyclophosphamide and/or etoposide), or had previously failed G ± P mobilization. To appropriately evaluate the impact of ICM among those who potentially could have received it, we utilized a propensity score matching (PSM) approach whereby ICM patients were compared to a cohort of non-CM patients matched on pre-ASCT factors most strongly associated with the receipt of ICM. Of 451 patients identified, 61 (13.5%) received ICM (PACE-based, n = 45; hyper-CVAD-based, n = 16). Post-ICM/pre-ASCT, 11 patients (18%) required admission for neutropenic fever and/or infection. Among 51 evaluable patients, the overall response rate was 31%; however, 46 of 55 evaluable patients (84%) saw a reduction in M-spike and/or involved free light chains. Among those evaluated with longitudinal peripheral blood flow cytometry (n = 8), 5 patients (63%) cleared circulating blood PCs post-ICM. Compared to patients mobilized with non-CM, ICM patients collected a slightly greater median number of CD34+ cells (10.8 versus 10.2 × 10⁶/kg, P = .018). The median follow-up was 30.6 months post-ASCT. In a PSM multivariable analysis, ICM was associated with significantly improved EFS (hazard ratio [HR] 0.30, 95% CI 0.14 to 0.67, P = .003), but not improved OS (HR 0.38, 95% CI 0.10 to 1.44, P = .2). ICM was associated with longer post-ASCT inpatient duration (+4.1 days, 95% CI, 2.4 to 5.8, P < .001), more febrile days (+0.96 days, 95% CI 0.50 to 1.4, P < .001), impaired platelet engraftment (HR 0.23, 95% CI 0.06 to 0.87, P = .031), more bacteremia (OR 3.41, 95% CI 1.20 to 9.31, P = .018), and increased antibiotic usage (cefepime: +2.3 doses, 95% CI 0.39 to 4.1, P = .018; vancomycin: +1.0 doses, 95% CI 0.23 to 1.8, P = .012). ICM was independently associated with improved EFS in a matched analysis involving MM patients with excessive disease burden at pre-ASCT workup. This benefit came at the cost of longer inpatient duration, more febrile days, greater incidence of bacteremia, and increased antibiotic usage in the immediate post-ASCT setting. Our findings suggest that ICM could be considered for a subset of MM patients, but its use must be weighed carefully against additional toxicity.

Comparison of two autologous hematopoietic stem cell mobilization strategies in patients with multiple myeloma: CE plus G-CSF versus G-CSF only: A single-center retrospective analysis

BACKGROUND

Despite recent advances in the treatment of multiple myeloma, high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (ASCT) remains an essential therapeutic keystone. As for the stem cell mobilization procedure, different regimens have been established, usually consisting of a cycle of chemotherapy followed by application of granulocyte-colony stimulating factor (G-CSF), although febrile neutropenia is a common complication. Following national guidelines, our institution decided to primarily use G-CSF only mobilization during the COVID-19 pandemic to minimize the patients' risk of infection and to reduce the burden on the health system.

STUDY DESIGN AND METHODS

In this retrospective single-center analysis, the efficacy and safety of G-CSF only mobilization was evaluated and compared to a historic control cohort undergoing chemotherapy-based mobilization by cyclophosphamide and etoposide (CE) plus G-CSF.

RESULTS

Although G-CSF only was associated with a higher need for plerixafor administration (p < .0001) and a higher number of apheresis sessions per patient (p = .0002), we were able to collect the target dose of hematopoietic stem cells in the majority of our patients. CE mobilization achieved higher hematopoietic stem cell yields (p = .0015) and shorter apheresis sessions (p < .0001) yet was accompanied by an increased risk of febrile neutropenia (p < .0001). There was no difference in engraftment after ASCT.

DISCUSSION

G-CSF only mobilization is a useful option in selected patients with comorbidities and an increased risk of serious infections, especially in the wintertime or in future pandemics.

Peripheral blood stem cell mobilisation following bortezomib, lenalidomide and dexamethasone induction for multiple myeloma: a real-world single-centre experience

BACKGROUND

Bortezomib, lenalidomide and dexamethasone (VRd) is now the standard-of-care induction therapy for newly diagnosed transplant-eligible multiple myeloma patients, replacing bortezomib, cyclophosphamide and dexamethasone (VCD) therapy. Lenalidomide can negatively impact stem cell yield because of its myelosuppressive effects, although studies have shown that the latter can be overcome with the use of cyclophosphamide for peripheral blood stem cell (PBSC) mobilisation.

AIMS AND METHODS

To investigate whether lenalidomide impacts on PBSC mobilisation and to evaluate the optimal mobilisation strategy post VRd induction, we performed a retrospective review of 56 myeloma patients at a single centre who had PBSC mobilisation between January 2019 and March 2021 and compared three cohorts: (i) VCD induction; mobilisation with granulocyte colony-stimulating factor (G-CSF) alone (n = 23); (ii) four cycles VRd induction; mobilisation with G-CSF and cyclophosphamide (G-CSF + Cyclo) (n = 20); and (iii) three cycles VRd induction; mobilisation with G-CSF alone (n = 13).

RESULTS

There was no difference in the mean total CD34 count between VCD and VRd patients who had G-CSF mobilisation (6.27 × 106 /kg vs 5.50 × 106 /kg, P > 0.99). VRd patients mobilised with G-CSF + Cyclo achieved higher mean total CD34 counts compared with G-CSF alone (8.89 × 106 /kg vs 5.50 × 106 /kg, P = 0.04). The majority of VRd patients who had G-CSF + Cyclo (19 of 20; 95%) collected sufficient cells for two or more autologous stem cell transplants (ASCTs), regardless of whether this was required, compared with eight of 13 (62%) VRd patients who had G-CSF alone.

CONCLUSION

We conclude that successful PBSC mobilisation for at least one ASCT is possible after three cycles of VRd induction using G-CSF alone. The upfront use of a cyclophosphamide-based mobilisation strategy has a role in patients who have had VRd induction, where the aim is to collect enough stem cells for two or more ASCTs.

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.

High Efficacy of Stem Cell Mobilization With Etoposide+Cytarabine Plus G-CSF in Patients With Multiple Myeloma

Background

Efficient mobilization of CD34+ hematopoietic stem cells plays a vital role in successful autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM), especially in cases with high-risk cytogenetic recommended for tandem ASCT. However, the optimal mobilization strategy remains a matter of debate in the era of lenalidomide. The combination of etoposide with Cytarabine plus G-CSF as a novel mobilization regimen in MM has not been reported previously.

Methods

This research retrospectively studied mobilization efficacy and safety using etoposide combined with Cytarabine (etoposide 50–100 mg/m², qd d1–3; AraC 0.5 g/m², q12h d1~3) plus G-CSF (5 µg/kg/day, from d5 until the day of apheresis) in 128 patients with MM. 70(54.7%) patients received lenalidomide-based induction regimens treatment

Results

A median of 27.75×10⁶ CD34+ cells/kg was collected in the first apheresis, and 28.23×10⁶ CD34+ cells/kg were collected overall. Of the 128 patients, all achieved adequate collection (≥2×10⁶ CD34+ cells/kg), 121(94.5%) achieved optimal collection for single ASCT (≥5×10⁶ CD34+ cells/kg), and 114(89.1%) harvested optimal collection for tandem ASCT (≥10×10⁶ CD34+ cells/kg). In particular, the target yield of optimal collection for tandem ASCT was reached in 82.8% (106/128) by a single apheresis procedure. 14 patients obtained deeper response post mobilization. In multivariate analysis, cycles of prior chemotherapy independently affected the optimal achievement of CD34+ cells (p=0.004, OR 0.695, 95% CI 0.544~0.888). Previous lenalidomide exposure did not significantly impair CD34+ cells collection. Although 68% episodes of antibiotic usage were observed, no severe infection or treatment-related mortality occurred.

Conclusion

Stem cell mobilization with Etoposide + Cytarabine plus G-CSF was highly efficient and safe in patients with MM, which could be considered in high-risk MM patients who were referred for tandem ASCT.

The association of mobilising regimen on immune reconstitution and survival in myeloma patients treated with bortezomib, cyclophosphamide and dexamethasone induction followed by a melphalan autograft

G-CSF only mobilisation has been shown to enhance immune reconstitution early post-transplant, but its impact on survival remains uncertain. We undertook a retrospective review of 12 transplant centres to examine overall survival (OS) and time to next treatment (TTNT) following melphalan autograft according to mobilisation method (G-CSF only vs. G-CSF and cyclophosphamide [CY]) in myeloma patients uniformly treated with bortezomib, cyclophosphamide and dexamethasone induction. Six centres had a policy to use G-CSF alone and six to use G-CSF + CY. Patients failing G-CSF only mobilisation were excluded. 601 patients were included: 328: G-CSF + CY, 273: G-CSF only. Mobilisation arms were comparable in terms of age, Revised International Staging System (R-ISS) groups and post-transplant maintenance therapy. G-CSF + CY mobilisation generated higher median CD34 + yields (8.6 vs. 5.5 × 10⁶/kg, p < 0.001). G-CSF only mobilisation was associated with a significantly higher lymphocyte count at day 15 post-infusion (p < 0.001). G-CSF only mobilisation was associated with significantly improved OS (aHR = 0.60, 95%CI 0.39-0.92, p = 0.018) and TTNT (aHR = 0.77, 95%CI 0.60-0.97, p = 0.027), when adjusting for R-ISS, disease-response pre-transplant, age and post-transplant maintenance therapy. This survival benefit may reflect selection bias in excluding patients with unsuccessful G-CSF only mobilisation or may be due to enhanced autograft immune cell content and improved early immune reconstitution.

Stem Cell Mobilization in Multiple Myeloma: Comparing Safety and Efficacy of Cyclophosphamide +/- Plerixafor versus Granulocyte Colony-Stimulating Factor +/- Plerixafor in the Lenalidomide Era

Growth factor and chemotherapy-based stem cell mobilization strategies are commonly used to treat patients with multiple myeloma. We retrospectively compared 398 patients mobilized between 2017 and 2020 using either cyclophosphamide (4 g/m²) plus granulocyte colony-stimulating factor (G-CSF) or G-CSF alone, with on demand plerixafor (PXF) in both groups. Although total CD34⁺ yield was higher after chemomobilization compared with G-CSF +/- PXF (median, 13.6 × 10⁶/kg versus 4.4 × 10⁶/kg; P < .01), achievement of ≥2 × 10⁶ CD34⁺ cells (95% versus 93.7%; P = .61) and rates of mobilization failure (5% versus 6.3%; P = .61) were similar. Fewer patients required PXF with chemomobilization (12.3% versus 49.5%; P < .01), and apheresis sessions were fewer (median, 1 [range, 1 to 4] versus 2 [range, 1 to 5]). The rate of complications, including neutropenic fever, emergency department visits, and hospitalizations, was higher after chemomobilization (30% versus 7.4%; P < .01). Previous use of ≤6 cycles of lenalidomide did not impair cell yield in either group. The median cost of mobilization was 17.4% lower in the G-CSF +/- PXF group (P = .01). Between group differences in time to engraftment were not clinically significant. Given similar rates of successful mobilization, similar engraftment time, and less toxicity and lower costs compared with chemomobilization, G-CSF with on-demand PXF may be preferable in myeloma patients with adequate disease control and limited lenalidomide exposure.

Chemotherapy-based versus chemotherapy-free stem cell mobilization (± plerixafor) in multiple myeloma patients: an Italian cost-effectiveness analysis

Given the availability and efficacy of the mobilizing agent plerixafor in augmenting hematopoietic progenitor cell mobilization with granulocyte colony-stimulating factor (G-CSF), there is a strong case for comparing the cost-effectiveness of mobilization with G-CSF + cyclophosphamide versus G-CSF alone. This study investigated the cost and effectiveness (i.e., successful 4 million-CD34⁺ collection) of G-CSF alone versus high-dose cyclophosphamide (4 g/m²) + G-CSF mobilization (± on-demand plerixafor) in patients with multiple myeloma (MM) eligible for autograft in Italy. A decision tree-supported cost-effectiveness analysis (CEA) model in MM patients was developed from the societal perspective. The CEA model compared G-CSF alone with cyclophosphamide 4 g/m² + G-CSF (± on-demand plerixafor) and was populated with demographic, healthcare and non-healthcare resource utilization data collected from a questionnaire administered to six Italian oncohematologists. Costs were expressed in Euro (€) 2019. The CEA model showed that G-CSF alone was strongly dominant versus cyclophosphamide + G-CSF ( ± on-demand plerixafor), with incremental savings of €1198.59 and an incremental probability of a successful 4 million-CD34⁺ apheresis (+0.052). Sensitivity analyses confirmed the robustness of the base-case results. In conclusion, chemotherapy-free mobilization (± on-demand plerixafor) is a “good value for money” option for MM patients eligible for autograft.

Low-Dose Cyclophosphamide versus Intermediate-High-Dose Cyclophosphamide versus Granulocyte Colony-Stimulating Factor Alone for Stem Cell Mobilization in Multiple Myeloma in the Era of Novel Agents: A Multicenter Retrospective Study

The optimal stem cell (SC) mobilization strategy for patients with multiple myeloma (MM) remains a matter of debate. Possible approaches include low or high doses of cyclophosphamide (Cy), other chemotherapeutic agents, or granulocyte colony-stimulating factor (G-CSF) alone. The scope of the study was to compare low-dose Cy plus G-CSF versus intermediate-high-dose Cy plus G-CSF versus G-CSF alone for SC mobilization in MM, in terms of efficacy and safety. We retrospectively analyzed 422 MM patients undergoing SC mobilization in 6 Italian centers, including 188 patients who received low-dose Cy (LD-Cy group, defined as 2 g/m²), 163 patients who received intermediate-high-dose Cy (HD-Cy group, defined as ≥ 3 g/m²), and 71 patients who received G-CSF alone (G-CSF group). The median peak of circulating CD34+ cells was 77/µL in the LD-Cy group, 92/µL in the HD-Cy group, and 55/µL in the G-CSF group (P = .0001). The median amount of SCs collected was 9.1 × 10⁶/kg, 9.7 × 10⁶/kg, and 5.6 × 10⁶/kg in the 3 groups, respectively (P = .0001). The rate of mobilization failure (defined as failure to collect ≥2 × 10⁶/kg) was 3.7% in the LD-Cy group, 3.4% in the HD-Cy group, and 4.3% in the G-CSF group (P = .9). The target SC dose of at least 4 × 10⁶/kg was reached in 90.4%, 91.1%, and 78.6% of the patients in these 3 groups, respectively (P = .014). The "on demand" use of plerixafor was higher in the G-CSF group (76%) compared with the LD-Cy group (19%) and the HD-Cy group (6%). In multivariate analysis, G-CSF mobilization and previous use of melphalan or radiotherapy were independently associated with failure to collect the target SC dose of ≥4 × 10⁶/kg. No impacts of age, blood counts, or previous treatment with lenalidomide, bortezomib, or carfilzomib were observed. Our results suggest that LD-Cy may be considered for successful SC mobilization in patients with MM.

Plerixafor on-demand in association with low-dose cyclophosphamide and G-CSF in the mobilization of patients with multiple myeloma: High effectiveness, low toxicity, and affordable cost

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In CD34 mobilization of Multiple Myeloma patients, Cyclophosphamide at the dose of 4 gr/m2 is usually administered. A lower dose of Cyclophosphamide (1.5–2.0 gr/m2) has a lower mobilizing effect and, for this reason, this dose is not widely used in CD34+ cells mobilization.

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The use of Plerixafor on demand, however, could have changed these conclusions. We hypothesized that when used in conjunction with on-demand Plerixafor, low lose CTX is more advantageous than the higher dose.

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The results of this prospective trial support, indeed, the view that low dose Cyclophosphamide in association to on-demand PLX allows the reaching efficacy and low toxicity.

In CD34+ cells mobilization of patients with multiple myeloma (MM), the use of Cyclophosphamide (CTX) at a dose of 2 g/m² has low efficacy although also lower toxicity. The suboptimal mobilizing effect of low-dose CTX, however, may be overcome by plerixafor (PLX) on demand.

We conducted a prospective multicenter study in 138 patients with MM to evaluate CTX 2 g/m² in association with granulocyte-colony stimulating factor (G-CSF) and on-demand PLX. We compared results with a historical group of MM patients (n = 138) mobilized using CTX at a dose of 4 g/m².

CD34+ cells greater than 2 × 10⁶/kg in max three aphereses were harvested in 98.6% of patients in the on-demand PLX study group while in 84.0% in the historical group, (p = 0.0001). In the on-demand-PLX study group, a successful harvest greater than 5 × 10⁶/kg in max three aphereses was observed in 85.5% of patients versus 62.3% of patients in the historical control group, (p=0.0001). In the on-demand-PLX study group, 4.3% (6/138) of patients had febrile complications. Salvage mobilization in the on-demand PLX study group was 1.4%.

In conclusions, on-demand PLX + CTX 2 g/m2 + G-CSF 10 μg/kg has higher efficacy and lower toxicity compared with CTX 4 g/m2 + G-CSF. An analysis of costs is presented.

Low-dose cyclophosphamide and granulocyte colony-stimulating factor are sufficient for peripheral blood stem cell mobilization in patients with multiple myeloma

Autologous stem cell transplantation (ASCT), supported by high-dose chemotherapy, is the prevalent option for multiple myeloma (MM) treatment in candidates suitable for transplantation. Although granulocyte colony-stimulating factor (G-CSF) supported cyclophosphamide (CY) is used as the pre-ASCT mobilization regimen, there is no consensus on the optimal dosage of CY. Thus, in this study, we examined the results of 47 MM patients, who underwent ASCT after mobilization with intermediate (ID) or low-dose (LD) CY treatment supported with G-CSF. As the mobilization regimen, we used ID (2.4 g/m2) of CY in 22 patients, and LD (1 g/m2) of CY in 25 patients. Adequate doses of CD34+ cells were collected in both groups. At the same time, febrile neutropenia was observed to be less common in patients in the LD-CY group. Additionaly 96% of patients in LD-CY group did not need to be hospitalized during the mobilization. In conclusion, we think that mobilization with LD-CY and G-CSF is advantageous since it results in a sufficient amount of stem cells in addition to being advantageous in terms of patient safety and cost.

Cost and efficacy of peripheral stem cell mobilization strategies in multiple myeloma

Mobilization of peripheral blood stem cells (PBSC) can be performed using plerixafor, which is expensive, or high-dose cyclophosphamide (HDCy). We hypothesized that the overall cost of mobilization with plerixafor might not be greater if the cost of complication management was considered. We performed a cost analysis of these two strategies. This multicentric observational study recruited patients with myeloma who underwent a first PBSC mobilization. We considered direct medical costs, including hospitalization, mobilization agents, apheresis, and supportive treatments. We included 111 patients, 54 and 57 in the HDCy and plerixafor groups, respectively. Cost of mobilization with HDCy was 5097 ± 2982€ vs. 10958 ± 1789€ for plerixafor (p < 0.0001). Cost of agents used was 1287 ± 779€ vs. 6552 ± 509€, respectively (p = 0.0009). The mean number of days of hospitalization was 2 and 2.1 days, respectively (p = 0.035). All patients achieved the minimum PBSC collection target (p = 1.0); however, ASCT was performed with HDCy in 67% patients and with plerixafor in 86% (p = 0.02). Plerixafor mobilization incurred a greater cost, mostly due to the greater cost of the drug. Hospitalization length in the two groups was similar in our series. Interestingly, plerixafor appeared to be a very effective and safe mobilizing approach translating into a greater ASCT success.

Higher efficacy of intermediate dose cytarabine + G-CSF compared to cyclophosphamide + G-CSF in hematopoietic stem cell mobilization in patients with multiple myeloma

BACKGROUND

There are several regimens used in hematopoietic stem cell (HSC) mobilization in multiple myeloma (MM). Cyclophosphamide (Cy) is one of the most commonly used agents, although it does not always result in collecting adequate number of CD34+ cells. Recently, cytarabine (Ara-C) has been proposed as potentially efficient and safe option.

AIMS

Since the data regarding Ara-C in HSC mobilization is limited, the aim of our study was to compare retrospectively the efficiency and toxicity of G-CSF combined with either Ara-C or Cy in MM patients.

MATERIALS & METHODS

Of a total of 89 patients, 43 received low or intermediate doses of Cy, and 46 were treated with 800 mg/m² /day of Ara-C administered for two days.

RESULTS

The mean peak of CD34+ cells/ul in peripheral blood was 132 (range, 84-202) in Ara-C and 51 (range, 29-69) in Cy cohort (p < 0.001). The median number of collected CD34+ cells (×106/kg) was 10.3 (range, 4.2-17.9) vs 4.5 (range, 2.7-8.9), respectively (p < 0.001). Mobilization failure was observed in one patient in Ara-C cohort (2%) and in 8 patients treated with Cy (19%) (p = 0.013). In the Ara-C group 98% of patients obtained more than 4×106 CD34+ cells/kg required for tandem transplantation. Moreover, we observed a trend toward increased paraprotein levels measured at transplant compared to before HSC mobilization in Ara-C cohort and significantly higher transfusion rates in that group.

CONCLUSION

Our findings confirm higher HSC mobilization efficacy of Ara-C compared to Cy in MM patients. However, lower transfusions rate and better disease control of Cy may justify its use in some cases.

Inferior prognosis in poor mobilizing myeloma patients

INTRODUCTION

Induction treatment followed by autologous stem cell transplantation (ASCT) has been accepted as the standard treatment for multiple myeloma (MM) patients. Granulocyte colony stimulating agent (G-CSF), chemotherapy or agents likes plerixafor are being used for the mobilization of stem cells from bone marrow. In this study, we evaluated the impact of the mobilization methods on the outcome of MM patients after ASCT.

METHOD

The data of 205 MM patients who underwent ASCT at our center between December 2009 and January 2019 were retrospectively analyzed. Patients were divided into 2 groups as good mobilizers (patients who were mobilized with G-CSF alone) and poor mobilizers (patients who were failed to mobilize with G-CSF alone and mobilized with G-CSF + cylophosphomide or G-CSF + plerixafor).

RESULTS

The median progression free survival (PFS) was 18.27 ± 3.22 months in good mobilizers and 14.22 ± 3.7 months in poor mobilizers. In G-CSF + cyclophosphamide method median PFS was 15.4 ± 4.9 months wheras it was only 4 months in G-CSF + plerixafor method. We did not find a statistically significant difference between good and poor mobilizers regarding median PFS (p: 0.342). The median overall survival (OS) was found 34.48 ± 4.2 months in good mobilizers and 15.13 ± 5.78 months in poor mobilizers. In G-CSF + cyclophosphamide method median OS was 17 ± 14.01 months wheras it was 10.66 ± 7.68 months in G-CSF + plerixafor method. We found a statistically significant difference between good and poor mobilizers regarding median OS (p: 0.007*).

CONCLUSION

Our study shows that difficulty in stem cell mobilization is correlated with worse outcome.

Pharmacokinetic and pharmacodynamic study of lenograstim for hematopoietic stem cell mobilization: a prospective randomized study for optimal apheresis

BACKGROUND

This study evaluated the correlation between the pharmacokinetics and pharmacodynamics of granulocyte colony-stimulating factor (lenograstim) and the impact of initiation time of apheresis on stem cell mobilization in patients with multiple myeloma.

STUDY DESIGN AND METHODS

Twenty-four patients with multiple myeloma were randomized into one of the two groups (early vs. late). Lenograstim at 10 μg/kg/day once daily was injected for at least 4 consecutive days. Apheresis was initiated 2 hours after the fourth dose of lenograstim in the early collection group and 16 hours after the fourth dose of lenograstim in the late collection group. Blood sampling for pharmacokinetics was performed within 30 minutes before, and 1, 2, 6, and 24 hours after the fourth dose of lenograstim.

RESULTS

Overall, the two groups (early vs. late, n = 10 vs. 14) exhibited similar baseline characteristics including age, sex, subtype of myeloma, stage distribution, and myeloma-associated symptoms. No correlation was found between plasma lenograstim concentration and peripheral blood (PB) CD34+ cell counts or hematopoietic progenitor cells. In the late collection group, the median number of apheresis procedures for minimal collection was significantly lower (early vs. late: 2 vs. 1; p = 0.04) and there was a higher number of total collected PB CD34+ cells in a single session of apheresis (1.4 vs. 3.1; p = 0.06). There were no differences in median overall PB stem cell collection efficiency.

CONCLUSION

Late collection positively impacted the number of apheresis procedures for minimal collection, with numerically improved PB stem cell collection efficiency at first apheresis in patients with multiple myeloma.

The effect of the dexamethasone, cytarabine, and cisplatin (DHAP) regimen on stem cell mobilization and transplant outcomes of patients with non-Hodgkin's lymphoma who are candidates for up-front autologous stem cell transplantation

BACKGROUND/AIMS

Data on dexamethasone, cytarabine, and cisplatin (DHAP) as a mobilization regimen, compared to high-dose cyclophosphamide (HDC), for up-front autologous stem cell transplantation (ASCT) in non-Hodgkin's lymphoma (NHL) is limited.

METHODS

Consecutive patients with aggressive NHL treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or rituximab-CHOP who underwent chemomobilization using HDC or DHAP plus granulocyte-colony stimulating factor (G-CSF) for up-front ASCT were enrolled from three institutions between 2004 and 2014.

RESULTS

Ninety-six patients (57 men) were included. Sixty-five patients (67.7%) received HDC; and 31 (32.3%), DHAP. The total CD34+ cells mobilized were significantly higher in patients receiving DHAP (16.1 vs. 6.1 × 106/kg, p = 0.001). More patients achieved successful mobilization with DHAP (CD34+ cells ≥ 5.0 × 106/kg) compared to HDC (87.1% vs. 61.5%, respectively; p = 0.011), particularly within the first two sessions of apheresis (64.5% vs. 32.3%, respectively; p = 0.003). Mobilization failure rate (CD34+ cells < 2.0 × 106/kg) was significantly higher in patients receiving HDC (20.0% vs. 3.2%, p = 0.032). On multivariate analysis, the DHAP regimen (odds ratio, 4.12; 95% confidence interval, 1.12 to 15.17) was an independent predictor of successful mobilization. During chemomobilization, patients receiving HDC experienced more episodes of febrile neutropenia compared to patients receiving DHAP (32.3% vs. 12.9%, p = 0.043).

CONCLUSION

The DHAP regimen was associated with a significantly higher efficacy for stem cell mobilization and lower frequency of febrile neutropenia. Therefore, DHAP plus G-CSF is an effective for mobilization in patients with aggressive NHL who were candidates for up-front ASCT.

Mobilization of Hematopoietic Progenitor Cells for Autologous Transplantation Using Pegfilgrastim and Plerixafor: Efficacy and Cost Implications

Filgrastim (FIL) is the most common growth factor combined with plerixafor for autologous hematopoietic progenitor cell mobilization, but requires daily, multi-injection administration. We adopted a standardized mobilization regimen with pegfilgrastim (PEG) and upfront plerixafor, allowing for a single injection given the long half-life and slow elimination of PEG. Between 2015 and 2017, a total of 235 patients with lymphoma or plasma cell dyscrasias underwent mobilization with PEG 6 mg on day 1 and upfront plerixafor 24 mg on day 3, followed by apheresis on day 4 regardless of peripheral blood CD34⁺ cells. The median CD34⁺ cells/mm³ in peripheral blood on first day of collection was 48 and median collection yield was 7.27 × 10⁶ CD34⁺ cells/kg (range, 0.32 to 39.6 × 10⁶ CD34⁺ cells/kg) after a mean of 1.6 apheresis collections. Overall, 83% of patients achieved the mobilization target, and 95% reached the minimum necessary CD34⁺ cell yield to proceed with transplantation (2 × 10⁶ CD34⁺ cells/kg). Because FIL is weight-based and dosed daily, the cost comparison with PEG is influenced by patient weight and number of apheresis sessions required. A cost simulation using actual patient data indicates that PEG is associated with lower cost than FIL for the majority of patients. Autologous hematopoietic progenitor cell mobilization with PEG and plerixafor is practical, effective, and not associated with increased cost compared with FIL mobilization.

Improved progression-free and event-free survival in myeloma patients undergoing PBSCH receiving a cyclophosphamide + G-CSF regimen than G-CSF alone

Two regimens are commonly used for peripheral blood hematopoietic stem cell harvesting (PBSCH) in multiple myeloma: high-dose cyclophosphamide (HD-CY) + granulocyte-colony stimulating factor (G-CSF), and G-CSF alone. The objective of the present study was to evaluate the anti-myeloma effect of the PBSCH regimen including HD-CY. We retrospectively assessed harvesting efficiency, complications, and anti-myeloma effects in 115 patients receiving HD-CY + G-CSF (HD-CY group) and 32 patients receiving G-CSF alone (G-alone group). We collected > 2 × 10⁶ CD34-positive cells/kg from 93 and 75% of patients in the HD-CY and G-alone groups, respectively (P = 0.0079). The mean HSC count was also higher in the HD-CY group. No severe complications were observed in the G-alone group, whereas 66% of patients in the HD-CY group were treated with intravenous antibiotics. The median progression-free and event-free survival (PFS and EFS) were longer in the HD-CY group than in the G-alone group (28 vs. 18 months and 25 vs. 13 months, respectively; P = 0.0127 and 0.0139), with no difference in median overall survival. HD-CY showed anti-myeloma effect, as verified by prolonged EFS and PFS, when a vincristine, doxorubicin, and dexamethasone regimen was administered as induction before PBSCH.

Management of mobilization failure in 2017

In contemporary clinical practice, almost all allogeneic transplantations and autologous transplantations now capitalize on peripheral blood stem cells (PBSCs) as opposed to bone marrow (BM) for the source of stem cells. In this context, granulocyte colony-stimulating factor (G-CSF) plays a pivotal role as the most frequently applied frontline agent for stem cell mobilization. For patients classified as high-risk, chemotherapy based mobilization regimens can be preferred as a first choice and it is notable that this also used for remobilization. Mobilization failure occurs at a rate of 10%-40% with traditional strategies and it typically leads to low-efficiency practices, resource wastage, and delayed in treatment intervention. Notably, however, several factors can impact the effectiveness of CD34⁺ progenitor cell mobilization, including patient age and medical history (prior chemotherapy or radiotherapy, disease and marrow infiltration at the time of mobilization). In recent years, main (yet largely ineffective) approach was to increase G-CSF dose and add SCF, but novel and promising pathways have been opened up by the synergistic impact of a reversible inhibitor of CXCR4, plerixafor, with G-CSF. The literature shows to its favorable results in upfront and failed mobilizers, and it is necessary to use plerixafor (or equivalent agents) to optimize HSC harvest in poor mobilizers. Different CXCR4 inhibitors, growth hormone, VLA4 inhibitors, and parathormone, have been cited as new agents for mobilization failure in recent years. In view of the above considerations, the purpose of this paper is to examine the mobilization of PBSC while focusing specifically on poor mobilizers.

Peripheral blood stem cell mobilization in multiple myeloma: Growth factors or chemotherapy?

High-dose therapy followed by autologous hematopoietic stem cell (HSC) transplant is considered standard of care for eligible patients with multiple myeloma. The optimal collection strategy should be effective in procuring sufficient HSC while maintaining a low toxicity profile. Currently available mobilization strategies include growth factors alone, growth factors in combination with chemotherapy, or growth factors in combination with chemokine receptor antagonists; however, the optimal strategy has yet to be elucidated. Herein, we review the risks and benefits of each approach.

Single Dose Preemptive Plerixafor for Stem Cell Mobilization for ASCT After Lenalidomide Based Therapy in Multiple Myeloma: Impact in Resource Limited Setting

Peripheral blood stem cell mobilization with cytokines for autologous stem cell transplant in multiple myeloma is adversely affected by initial induction therapy consisting of either Lenalidomide or cytotoxic drugs, with failure rates of up to 45%. The use of Plerixafor with G-CSF for PBSC mobilisation significantly improves the chances of a successful mobilization. Plerixafor is a costly therapy and increases the overall costs of ASCT which can affect the number of patients being taken up for ASCT in resource limited settings. We prospectively studied the impact of single dose preemptive Plerixafor for PBSC mobilization in patients with prior Lenalidomide exposure. 26 patients who had received Lenalidomide based induction protocol underwent PBSC mobilisation during the study period with G-CSF 10 μg/kg/day SC for 4 days and single dose preemptive Plerixafor 240 μg/kg SC stat 11 h before the scheduled PB stem cell harvest on D5, based on a D4 PB CD34+ counts of <20/μL. A median of 07 cycles of Lenalidomide based combination therapy was used for induction therapy prior to ASCT. 84% patients underwent successful mobilization with one sitting of stem cell harvest post a single dose of Inj Plerixafor. 7.6% patients failed to mobilise the predefined minimum cell dose of CD34 and could not be taken up for ASCT. The median CD34% of the harvest bag sample was 0.33% (0.1-0.97%). Injection site erythema (34%), paresthesia's (34%) and nausea (30%) were the commonest adverse events reported post Inj Plerixafor. We did a real-world cost analysis for a resource limited setting for PBSC mobilization and found significant cost savings for the preemptive Plerixafor group.

How to manage poor mobilizers for high dose chemotherapy and autologous stem cell transplantation?

Today, peripheral blood stem cells are the preferred source of stem cells over bone marrow. Therefore, mobilization plays a crutial role in successful autologous stem cell transplantation. Poor mobilization is generally defined as failure to achieve the target level of at least 2×10⁶ CD34⁺ cells/kg body weight. There are several strategies to overcome poor mobilization: 1) Larger volume Leukapheresis (LVL) 2) Re-mobilization 3) Plerixafor 4) CM+Plerixafor (P)+G-CSF and 5) Bone Marrow Harvest. In this review, the definitions of successful and poor mobilization are discussed. Management strategies for poor mobilization are defined. The recent research on new agents are included.

Bendamustine, etoposide and dexamethasone to mobilize peripheral blood hematopoietic stem cells for autologous transplantation in patients with multiple myeloma

Chemotherapeutic agents without cross-resistance to prior therapies may enhance PBSC collection and improve patient outcomes by exacting a more potent direct antitumor effect before autologous stem cell transplant. Bendamustine has broad clinical activity in transplantable lymphoid malignancies, but concern remains over the potential adverse impact of this combined alkylator-nucleoside analog on stem cell mobilization. We performed a prospective, nonrandomized phase II study including 34 patients with multiple myeloma (MM) (n=34; International Staging System (ISS) stages I (35%), II (29%) and III (24%); not scored (13%)) to evaluate bendamustine's efficacy and safety as a stem cell mobilizing agent. Patients received bendamustine (120 mg/m2 IV days 1, 2), etoposide (200 mg/m2 IV days 1-3) and dexamethasone (40 mg PO days 1- 4) (bendamustine, etoposide and dexamethasone (BED)) followed by filgrastim (10 μg/kg/day SC; through collection). All patients (100%) successfully yielded stem cells (median of 21.60 × 106/kg of body weight; range 9.24-55.5 × 106/kg), and 88% required a single apheresis. Six nonhematologic serious adverse events were observed in 6 patients including: neutropenic fever (1, grade 3), bone pain (1, grade 3) and renal insufficiency (1, grade 1). In conclusion, BED safely and effectively mobilizes hematopoietic stem cells.

Autologous Stem Cell Mobilization in the Age of Plerixafor

BACKGROUND

Autologous stem cell transplantation remains important in the treatment of myeloma and relapsed lymphoma. Plerixafor has been shown to significantly enhance stem cell mobilization but is very expensive.

PATIENTS AND METHODS

We evaluated plerixafor use in the 3-year period after its approval in December 2008.

RESULTS

A total of 277 patients with myeloma and lymphoma had stem cell mobilization; 97.5% were successfully mobilized, including 41.5% who received plerixafor. Plerixafor was generally used for rescue after suboptimal granulocyte-colony stimulating factor (G-CSF) mobilization ("just in time") or for remobilization after an unsuccessful attempt with chemotherapy plus G-CSF. In addition, 10% of patients received planned G-CSF plus plerixafor because of high risk factors for inadequate collection. Rescue plerixafor was more effective in patients with myeloma than lymphoma as after 1 dose of plerixafor; 85% versus 55% collected a minimum number of stem cells (2 × 10E6 CD34 cells/kg) for 1 transplant and 51% versus 15% collected > 5 × 10E6 CD34 cells/kg. After transplantation, there were no significant differences in engraftment as a consequence of plerixafor use. Among all patients, there were less platelet transfusions in patients provided ≥ 3.5 × 10E6 CD34(+) cells/kg.

CONCLUSION

With the judicious use of plerixafor, nearly all patients can collect enough stem cells to proceed to transplantation. Further studies, including hematologic tolerance to posttransplantation therapy, are required to determine the cost-effectiveness of using plerixafor to convert adequate to more optimal mobilizers.

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.

The High Effect of Chemomobilization with High-Dose Etopside + Granulocyte-Colony Stimulating Factor in Autologous Hematopoietic Peripheral Blood Stem Cell Transplantation: A Single Center Experience

Autologous hematopoietic stem cell transplantation (auto-HSCT) provides hematopoietic support after high-dose chemotherapy and is the standard of care for patients with multiple myeloma (MM), chemo sensitive relapsed high or intermediate grade non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). However, yields of hematopoietic stem cells vary greatly between patients, and the optimal strategy to mobilize hematopoietic stem cells into peripheral blood for collection has not been defined yet. We investigated the efficacy and safety of chemo mobilization with an intermediate dose etoposide (VP-16; 200 mg/m² on days 1-3) and granulocyte-colony stimulating factor (G-CSF)(5 µg/kg twice daily from day 4 through the final day of collection). We reviewed our institutional experience with 91 patients (71 MM, 12 HL, 8 NHL) mobilized with this regimen. VP-16 + G-CSF resulted in successful mobilization in 95.55% of the patients (on one patient stem cell collection with plerixafor was applied), including 76 patients (83.52%) whose stem cells were collected successfully in a single day. Collection was managed between min. D8 and max. D17. Patient age, gender, exposure to previous irradiation and chemotherapy, previous mobilization attempts, and disease characteristics were not considered during selection. Adverse effects of the regimen included supportive transfusions and fevers requiring hospitalization or intravenous antibiotics. VP-16 and G-CSF appears to be a safe and effective mobilization regimen for patients with multiple myeloma, non-Hodgkin’s lymphoma and Hodgkin’s lymphoma undergoing autologous stem cell transplantation, producing excellent stem cell yield with the majority of patients requiring 1 day of apheresis.

Selection of a mobilization regimen for multiple myeloma based on the response to induction therapy: granulocyte-colony stimulating factor (G-CSF) alone versus high-dose cyclophosphamide plus G-CSF

To evaluate the feasibility of selecting a mobilization regimen based on the response to induction therapy, we retrospectively analyzed 179 multiple myeloma patients who underwent stem cell mobilization. In comparison with patients who achieved at least a very good partial response (VGPR) to induction therapy and received granulocyte-colony stimulating factor (G-CSF) alone and patients who did not achieve a VGPR and received cyclophosphamide (CY) + G-CSF, treatment-related toxicity was greater and neutrophil engraftment was slower in the CY than the G-CSF group. The rate of requisite mobilization (≥ 2.0 × 10(6)/kg) was similar in both groups. Overall and progression-free survival was not different between patients in the G-CSF group and patients who achieved at least VGPR and received CY + G-CSF. In conclusion, response-adapted selection of a mobilization regimen is appropriate. G-CSF alone should be the preferred treatment for patients who achieved at least a VGPR to induction therapy.

A randomized phase II study of stem cell mobilization with cyclophosphamide+G-CSF or G-CSF alone after lenalidomide-based induction in multiple myeloma

The most common means of mobilizing autologous stem cells is G-CSF alone or combined with cyclophosphamide (CY) to obtain sufficient CD34⁺ cells for one to two transplants. There are few prospective, randomized studies investigating mobilization regimens in multiple myeloma (MM), especially after lenalidomide-based induction. We designed this prospective, randomized study to compare low-dose CY 2 g/m²+G-CSF (arm A) and G-CSF alone (arm B) after lenalidomide-based up-front induction in MM. Of the 80 initially randomized patients, 69 patients were evaluable, 34 and 35 patients in arms A and B, respectively. The primary end point was the proportion of patients achieving a yield of ⩾3 × 10⁶/kg CD34⁺ cells with 1−2 aphereses, which was achieved in 94% and 77% in arms A and B, respectively (P=0.084). The median number of aphereses needed to reach the yield of ⩾3 × 10⁶/kg was lower in arm A than in arm B (1 vs 2, P=0.035). Two patients needed plerixafor in arm A and five patients in arm B (P=0.428). Although CY-based mobilization was more effective, G-CSF alone was successful in a great majority of patients to reach the defined collection target after three cycles of lenalidomide-based induction.

Contribution of chemotherapy mobilization to disease control in multiple myeloma treated with autologous hematopoietic cell transplantation

In patients with multiple myeloma (MM) undergoing autologous hematopoietic cell transplantation (auto-HCT), peripheral blood progenitor cells (PBPCs) may be collected following mobilization with growth factor alone (GF) or cytotoxic chemotherapy plus GF ( (CC+GF). It is uncertain whether the method of mobilization affects post-transplant outcomes. We compared these mobilization strategies in a retrospective analysis of 968 patients with MM from the Center for International Blood and Marrow Transplant Research database who received an auto-HCT in the US and Canada between 2007 and 2012. The kinetics of neutrophil engraftment (≥ 0.5 × 10⁹/L) was similar between groups (13 vs. 13 days, P=0.69) while platelet engraftment (≥ 20 × 10⁹/L) was slightly faster with CC+GF (19 vs. 18 days, P=0.006). Adjusted 3-years PFS was 43% (95% C.I. 38–48) in GF and 40% (95% C.I. 35–45) in CC+GF, P=0.33. Adjusted 3-years OS was 82% (95% C.I. 78–86) vs. 80% (95% C.I. 75–84), P=0.43 and adjusted 5-year OS was 62% (95C.I. 54–68) vs. 60% (95% C.I. 52–67), P=0.76, for GF and CC+GF respectively. We conclude that MM patients undergoing auto-HCT have similar outcomes irrespective of the method of mobilization and found no evidence that the addition of chemotherapy to mobilization contributes to disease control.

Hematopoietic progenitor cell mobilization for autologous transplantation - a literature review

The use of high-dose chemotherapy with autologous support of hematopoietic progenitor cells is an effective strategy to treat various hematologic neoplasms, such as non-Hodgkin lymphomas and multiple myeloma. Mobilized peripheral blood progenitor cells are the main source of support for autologous transplants, and collection of an adequate number of hematopoietic progenitor cells is a critical step in the autologous transplant procedure. Traditional strategies, based on the use of growth factors with or without chemotherapy, have limitations even when remobilizations are performed. Granulocyte colony-stimulating factor is the most widely used agent for progenitor cell mobilization. The association of plerixafor, a C-X-C Chemokine receptor type 4 (CXCR4) inhibitor, to granulocyte colony stimulating factor generates rapid mobilization of hematopoietic progenitor cells. A literature review was performed of randomized studies comparing different mobilization schemes in the treatment of multiple myeloma and lymphomas to analyze their limitations and effectiveness in hematopoietic progenitor cell mobilization for autologous transplant. This analysis showed that the addition of plerixafor to granulocyte colony stimulating factor is well tolerated and results in a greater proportion of patients with non-Hodgkin lymphomas or multiple myeloma reaching optimal CD34⁺ cell collections with a smaller number of apheresis compared the use of granulocyte colony stimulating factor alone.

Optimizing mobilization strategies in difficult-to-mobilize patients: The role of plerixafor

Peripheral blood stem cell collection is currently the most widely used source for hematopoietic autologous transplantation. Several factors such as advanced age, previous chemotherapy, disease and marrow infiltration at the time of mobilization influence the efficacy of CD34(+) progenitor cell mobilization. Despite the safety and efficiency of the standard mobilization protocols (G-CSF ± chemotherapy), there is still a significant amount of mobilization failure rate (10-40%), which necessitate novel agents for effective mobilization. Plerixafor, is a novel agent, has been recently approved for mobilization of hematopoietic stem cells (HSCs). The combination of Plerixafor with G-CSF provides the collection of large numbers of stem cells in fewer apheresis sessions and can salvage those who fail with standard mobilization regimens. The development and optimization of practical algorithms for the use Plerixafor is crucial to make hematopoietic stem cell mobilization more efficient in a cost-effective way. This review is aimed at summarizing how to identify poor mobilizers, and define rational use of Plerixafor for planning mobilization in hard-to-mobilize patients.

Mobilization and transplantation patterns of autologous hematopoietic stem cells in multiple myeloma and non-Hodgkin lymphoma

BACKGROUND

The mobilization of hematopoietic stem cells can be a limiting factor for transplantation, yet little is known about how the availability of novel mobilizing agents has affected the practices of oncologists and transplant specialists.

METHODS

US-based oncologists (n = 48) and transplant specialists (n = 46) were separately surveyed with a partial overlap of assessed information.

RESULTS

More transplant specialists than oncologists believed that the time between referral and first consultation is adequate (89.1% vs 54.2%; P < .001). The presence of comorbidities was the most common reason for patients not being referred for transplantation. Among oncologists, 31.3% avoided cyclophosphamide and 16.7% avoided lenalidomide to prevent mobilization impairment in patients with multiple myeloma (MM). Chemotherapy mobilization for MM was used by 23.9% of transplant specialists due to higher CD34+ yields and by 21.7% due to its anti-MM effect. In non-Hodgkin lymphoma (NHL), 26.1% of transplant specialists used chemotherapy mobilization due to higher CD34+ yields, and 26.1% collected hematopoietic stem cells on the rebound prior to chemotherapy. With regard to plerixafor use in MM, 36.9% of transplant specialists reported that they did not use it, and 28.3% said they reserved it for second mobilization. In NHL, 4.3% of transplant specialists reported not using plerixafor, and 39.1% reserved it for second mobilization.

CONCLUSIONS

Educational needs were identified to promote adequate referral for transplantation as well as successful and cost-effective methods for the mobilization of hematopoietic stem cells.

Cyclophosphamide-based hematopoietic stem cell mobilization before autologous stem cell transplantation in newly diagnosed multiple myeloma

High-dose cyclophosphamide (Cy) is frequently employed for peripheral blood mobilization of hematopoietic stem cells before high-dose chemotherapy with autologous stem cell transplantation (ASCT) in multiple myeloma (MM). The benefit of mobilization with Cy over filgrastim (granulocyte colony-stimulating factor; G-CSF) alone is unclear. Between 2000 and 2008, 167 patients with newly diagnosed MM underwent single ASCT after melphalan conditioning at our institution. Seventy-three patients were mobilized with G-CSF alone, and 94 patients with Cy plus G-CSF (Cy+G-CSF). We retrospectively analyzed Cy's impact on both toxicity and efficacy. Mobilization efficiency was augmented by Cy; a mean total of 12 versus 5.8 × 10(6) CD34+ cells/kg were collected from patients mobilized with Cy+G-CSF versus G-CSF, respectively, (P < 0.01), over a mean of 1.6 versus 2.2 days of peripheral blood apheresis (p = 0.001). Mobilization-related toxicity was also, however, augmented by Cy; 14% of Cy+G-CSF patients were hospitalized because of complications versus none receiving G-CSF (P < 0.0001). Toxicity, including death, related to ASCT was similar between cohorts. Regarding long-term outcomes, multivariate analysis revealed no difference for Cy+G-CSF versus G-CSF (hazard ratio 0.8 for event-free survival [95% confidence interval {CI} 0.57-1.25] and 0.96 for overall survival [95% CI 0.61-1.54]). In summary, we show that mobilization with Cy increases toxicity without positively impacting long-term outcomes in MM. Our findings place into question Cy's benefit as a routine component of stem cell mobilization regimens in MM. Randomized trials are needed to elucidate the risks and benefits of Cy more definitively.

How we manage autologous stem cell transplantation for patients with multiple myeloma

An estimated 22 350 patients had multiple myeloma diagnosed in 2013, representing 1.3% of all new cancers; 10 710 deaths are projected, representing 1.8% of cancer deaths. Approximately 0.7% of US men and women will have a myeloma diagnosis in their lifetime, and with advances in therapy, 77 600 US patients are living with myeloma. The 5-year survival rate was 25.6% in 1989 and was 44.9% in 2005. The median age at diagnosis is 69 years, with 62.4% of patients aged 65 or older at diagnosis. Median age at death is 75 years. The rate of new myeloma cases has been rising 0.7% per year during the past decade. The most common indication for autologous stem cell transplantation in the United States is multiple myeloma, and this article is designed to provide the specifics of organizing a transplant program for multiple myeloma. We review the data justifying use of stem cell transplantation as initial management in myeloma patients. We provide selection criteria that minimize the risks of transplantation. Specific guidelines on mobilization and supportive care through the transplant course, as done at Mayo Clinic, are given. A review of the data on tandem vs sequential autologous transplants is provided.

Prediction of poor mobilization of autologous CD34+ cells with growth factor in multiple myeloma patients: implications for risk-stratification

It is unknown whether clinical characteristics can successfully predict which multiple myeloma (MM) patients would be poor mobilizers with growth factor (GF) alone so they can be assigned to mobilization with chemotherapy + GF or GF + plerixafor. MM patients (N = 477) who underwent autologous mobilization with GF were retrospectively reviewed and assigned into training and validation cohorts. In multiple regression analysis, age, platelet count at time of mobilization, type of GF utilized, and extent of exposure to lenalidomide independently correlated with peripheral blood (PB)-CD34+ and were integrated in a predicting score (PS) for poor mobilizers, defined as PB-CD34+ < 20/mm(3) 4 days after initiation of GF. There was no correlation between institution, gender, time between diagnosis, and mobilization or plasma cells in the bone marrow at time of mobilization and PBCD34+. The PS cut-off found in the training cohort to have 90% sensitivity for prediction of poor mobilizers performed with 89.7% sensitivity but only 34.8% specificity in the validation cohort. Conversely, the PS cut-off developed to have 90% specificity performed with 86.9% specificity but only 37% sensitivity. We conclude that clinical characteristics identifiable before initiation of mobilization should not be used to stratify MM patients for different mobilization strategies.

Optimizing autologous stem cell mobilization strategies to improve patient outcomes: consensus guidelines and recommendations

Autologous hematopoietic stem cell transplantation (aHSCT) is a well-established treatment for malignancies such as multiple myeloma (MM) and lymphomas. Various changes in the field over the past decade, including the frequent use of tandem aHSCT in MM, the advent of novel therapies for the treatment of MM and lymphoma, and the addition of new stem cell mobilization techniques, have led to the need to reassess current stem cell mobilization strategies. Mobilization failures with traditional strategies are common and result in delays in treatment and increased cost and resource utilization. Recently, plerixafor-containing strategies have been shown to significantly reduce mobilization failure rates, but the ideal method to maximize stem cell yields and minimize costs associated with collection has not yet been determined. A panel of experts convened to discuss the currently available data on autologous hematopoietic stem cell mobilization and transplantation and to devise guidelines to optimize mobilization strategies. Herein is a summary of their discussion and consensus.

Hematopoietic progenitor cell mobilization using low-dose cyclophosphamide and granulocyte colony-stimulating factor for multiple myeloma

High-dose chemotherapy (HDT) supported by autologous stem cell transplantation (ASCT) has long been one of the standards of care for younger patients with multiple myeloma (MM). Cyclophosphamide (CY) plus granulocyte colony-stimulating factor (G-CSF) has been the conventional preparation for hematopoietic progenitor cell (HPC) mobilization, although the optimal dosage of CY in this setting has not yet been clearly defined. This study investigated the efficacy and safety of low-dose (LD-)CY (1.5 g/m(2)) plus G-CSF for conditioning for HPC apheresis harvest (HPC-A) in 18 MM patients, and compared it with a regimen consisting of intermediate-dose (ID)-CY (4 g/m(2)) plus G-CSF for 13 MM patients. Eleven patients in the former and six in the latter were treated with bortezomib (BTZ) during the induction therapy. Both regimens were comparably effective in terms of CD34(+) cell yields, while adverse events, such as leukopenia, thrombocytopenia, and febrile neutropenia, occurred significantly less frequently in the LD-CY cohort. All patients in LD-CY cohort started and completed their apheresis on day 7 or 8, whereas for the ID-CY cohort the day of first apheresis varied widely from day 8 to 15. These findings indicate that the LD-CY regimen is as effective as ID-CY for HPC mobilization, while the former is clearly more practicable and convenient than the ID-CY regimen for patients with MM.

Regulatory systems in bone marrow for hematopoietic stem/progenitor cells mobilization and homing

Regulation of hematopoietic stem cell release, migration, and homing from the bone marrow (BM) and of the mobilization pathway involves a complex interaction among adhesion molecules, cytokines, proteolytic enzymes, stromal cells, and hematopoietic cells. The identification of new mechanisms that regulate the trafficking of hematopoietic stem/progenitor cells (HSPCs) cells has important implications, not only for hematopoietic transplantation but also for cell therapies in regenerative medicine for patients with acute myocardial infarction, spinal cord injury, and stroke, among others. This paper reviews the regulation mechanisms underlying the homing and mobilization of BM hematopoietic stem/progenitor cells, investigating the following issues: (a) the role of different factors, such as stromal cell derived factor-1 (SDF-1), granulocyte colony-stimulating factor (G-CSF), and vascular cell adhesion molecule-1 (VCAM-1), among other ligands; (b) the stem cell count in peripheral blood and BM and influential factors; (c) the therapeutic utilization of this phenomenon in lesions in different tissues, examining the agents involved in HSPCs mobilization, such as the different forms of G-CSF, plerixafor, and natalizumab; and (d) the effects of this mobilization on BM-derived stem/progenitor cells in clinical trials of patients with different diseases.

Peripheral blood stem cell mobilization in multiple myeloma patients treat in the novel therapy-era with plerixafor and G-CSF has superior efficacy but significantly higher costs compared to mobilization with low-dose cyclophosphamide and G-CSF

Studies comparing the efficacy and cost of peripheral blood stem and progenitor cells mobilization with low-dose cyclophosphamide (LD-CY) and granulocyte-colony stimulating factor (G-CSF) against plerixafor and G-CSF, in multiple myeloma (MM) patients treated in the novel therapy-era are not available. Herein, we report mobilization outcomes of 107 patients who underwent transplantation within 1-year of starting induction chemotherapy with novel agents. Patients undergoing mobilization with LD-CY (1.5 gm/m(2)) and G-CSF (n = 74) were compared against patients receiving plerixafor and G-CSF (n = 33). Compared to plerixafor, LD-CY was associated with a significantly lower median peak peripheral blood CD34+ cell count (68/µL vs. 36/µL, P = 0.048), and lower CD34+ cell yield on day 1 of collection (6.9 × 10(6)/kg vs. 2.4 × 10(6)/kg, P = 0.001). Six patients (8.1%) in the LD-CY group experienced mobilization failure, compared to none in the plerixafor group. The total CD34+ cell yield was significantly higher in the plerixafor group (median 11.6 × 10(6)/kg vs. 7 × 10(6)/kg; P-value = 0.001). Mobilization with LD-CY was associated with increased (albeit statistically non-significant) episodes of febrile neutropenia (5.4% vs. 0%; P = 0.24), higher use of intravenous antibiotics (6.7% vs. 3%; P = 0.45), and need for hospitalizations (9.4% vs. 3%; P = 0.24). The average total cost of mobilization in the plerixafor group was significantly higher compared to the LD-CY group ($28,980 vs. $19,626.5 P-value < 0.0001). In conclusion, in MM plerixafor-based mobilization has superior efficacy, but significantly higher mobilization costs compared to LD-CY mobilization. Our data caution against the use of LD-CY in MM patients for mobilization, especially after induction with lenalidomide-containing regimens.