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

Effect of Autograft CD34+ Dose on Outcome in Pediatric Patients Undergoing Autologous Hematopoietic Stem Cell Transplant for Central Nervous System Tumors

Consolidation with autologous hematopoietic stem cell transplantation (HSCT) has improved survival for patients with central nervous system tumors (CNSTs). The impact of the autologous graft CD34+ dose on patient outcomes is unknown. We wanted to analyze the relationship between CD34+ dose, total nucleated cell (TNC) dose, and clinical outcomes, including overall survival (OS), progression-free survival (PFS), relapse, non-relapse mortality (NRM), endothelial-injury complications (EIC), and time to neutrophil engraftment in children undergoing autologous HSCT for CNSTs. A retrospective analysis of the CIBMTR database was performed. Children aged <10 years who underwent autologous HSCT between 2008 to 2018 for an indication of CNST were included. An optimal cut point was identified for patient age, CD34+ cell dose, and TNC, using the maximum likelihood method and PFS as an endpoint. Univariable analysis for PFS, OS, and relapse was described using the Kaplan-Meier estimator. Cox models were fitted for PFS and OS outcomes. Cause-specific hazards models were fitted for relapse and NRM. One hundred fifteen patients met the inclusion criteria. A statistically significant association was identified between autograft CD34+ content and clinical outcomes. Children receiving >3.6×106/kg CD34+ cells experienced superior PFS (p = .04) and OS (p = .04) compared to children receiving ≤3.6 × 106/kg. Relapse rates were lower in patients receiving >3.6 × 106/kg CD34+ cells (p = .05). Higher CD34+ doses were not associated with increased NRM (p = .59). Stratification of CD34+ dose by quartile did not reveal any statistically significant differences between quartiles for 3-year PFS (p = .66), OS (p = .29), risk of relapse (p = .57), or EIC (p = .87). There were no significant differences in patient outcomes based on TNC, and those receiving a TNC >4.4 × 108/kg did not experience superior PFS (p = .26), superior OS (p = .14), reduced risk of relapse (p = .37), or reduced NRM (p = .25). Children with medulloblastoma had superior PFS (p < .001), OS (p = .01), and relapse rates (p = .001) compared to those with other CNS tumor types. Median time to neutrophil engraftment was 10 days versus 12 days in the highest and lowest infused CD34+ quartiles, respectively. For children undergoing autologous HSCT for CNSTs, increasing CD34+ cell dose was associated with significantly improved OS and PFS, and lower relapse rates, without increased NRM or EICs.

Stem Cell Mobilization Yields with Daratumumab- and Lenalidomide-Containing Quadruplet Induction Therapy in Newly Diagnosed Multiple Myeloma: Findings from the MASTER and GRIFFIN Trials

For eligible patients with newly diagnosed multiple myeloma (NDMM), standard of care includes induction therapy followed by autologous stem cell transplantation (ASCT). Daratumumab as monotherapy and in combination treatment is approved across multiple lines of therapy for multiple myeloma (MM), and lenalidomide is an effective and commonly used agent for induction and maintenance therapy in MM. However, there is concern that lenalidomide and daratumumab given as induction therapy might impair mobilization of stem cells for ASCT. Therefore, we assessed stem cell mobilization in patients following frontline induction therapy in the MASTER and GRIFFIN phase 2 clinical studies by examining stem cell mobilization yields, apheresis attempts, and engraftment outcomes for patients from each study. Adult transplantation-eligible patients with NDMM received induction therapy consisting of daratumumab plus carfilzomib/lenalidomide/dexamethasone (D-KRd) for four 28-day cycles in the single-arm MASTER trial or lenalidomide/bortezomib/dexamethasone (RVd) with or without daratumumab (D) for four 21-day cycles in the randomized GRIFFIN trial, followed by stem cell mobilization and ASCT in both studies. Institutional practice differed regarding plerixafor use for stem cell mobilization; the strategies were upfront (ie, planned plerixafor use) or rescue (ie, plerixafor use only after mobilization parameters indicated failure with granulocyte colony-stimulating factor [G-CSF] alone). Descriptive analyses were used to summarize patient characteristics, stem cell mobilization yields, and engraftment outcomes. In MASTER, 116 D-KRd recipients underwent stem cell mobilization and collection at a median of 24 days after completing induction therapy. In GRIFFIN, 175 patients (D-RVd, n = 95; RVd, n = 80) underwent mobilization at a median of 27 days after completing D-RVd induction therapy and 24 days after completing RVd induction therapy. Among those who underwent mobilization and collection, 7% (8 of 116) of D-KRd recipients, 2% (2 of 95) of D-RVd recipients, and 6% (5 of 80) of RVd recipients did not meet the center-specific minimally required CD34⁺ cell yield in the first mobilization attempt; however, nearly all collected sufficient stem cells for ASCT on remobilization. Among patients who underwent mobilization, plerixafor use, either upfront or as a rescue strategy, was higher in patients receiving D-KRd (97%; 112 of 116) and D-RVd (72%; 68 of 95) compared with those receiving RVd (55%; 44 of 80). The median total CD34⁺ cell collection was 6.0 × 10⁶/kg (range, 2.2 to 13.9 × 10⁶/kg) after D-KRd induction, 8.3 × 10⁶/kg (range, 2.6 to 33.0 × 10⁶/kg) after D-RVd induction, and 9.4 × 10⁶/kg (range, 4.1 to 28.7 × 10⁶/kg) after RVd induction; the median days for collection were 2, 2, and 1, respectively. Among patients who underwent mobilization, 98% (114 of 116) of D-KRd patients, 99% (94 of 95) of D-RVd patients, and 98% (78 of 80) of RVd patients underwent ASCT using median CD34⁺ cell doses of 3.2 × 10⁶/kg, 4.2 × 10⁶/kg, and 4.8 × 10⁶/kg, respectively. The median time to neutrophil recovery was 12 days in all 3 treatment groups across the 2 trials. Because both trials used different criteria to define platelet recovery, data on platelet engraftment using the same criteria are not available. Four cycles of daratumumab- and lenalidomide-based quadruplet induction therapy had a minimal impact on stem cell mobilization and allowed predictable stem cell harvesting and engraftment in all patients who underwent ASCT. Upfront plerixafor strategy may be considered, but many patients were successfully collected with the use of G-CSF alone or rescue plerixafor.

Plerixafor use in New Zealand 2016-2019: An Observational Study

INTRODUCTION

Plerixafor is used to mobilise CD34-positive stem cells for autologous transplantation to treat haematological malignancy. Funded in New Zealand since 2016, plerixafor can be used "pre-emptively" to salvage a failing first attempt or as a "rescue" strategy involving re-mobilising after 4 weeks. The rate of failed mobilisation and plerixafor uptake in New Zealand is not known, whilst international practice varies widely.

AIMS

To establish success rates for conditioning regimes used in New Zealand.

METHODS

We reviewed 203 consecutive patients with myeloma (n=122) or lymphoma (n=81) undergoing stem cell mobilisation between 1/1/2016 and 5/8/2019 at Christchurch hospital. We recorded demographics, conditioning regimens, harvest outcome and apheresis duration. Successful harvest was defined as collection of >2x10⁶ CD34+ cells.kg^-1 .

RESULTS

17% of patients received plerixafor. Harvest success rates for lymphoma and myeloma respectively were 77% and 86% with standard conditioning, 95% and 100% with "pre-emptive" plerixafor, and 71% and 89% with "rescue" plerixafor. "Pre-emptive" plerixafor was non-inferior to standard conditioning. Following local guidelines resulted in at least one successful harvest for 96% lymphoma and 99% myeloma patients.

CONCLUSION

Plerixafor strategies in New Zealand allow successful stem cell mobilisation for ≥96% of patients. Further research is required to investigate whether increased use would be cost-effective through reduced chemotherapy and apheresis duration, and improved graft quality. This article is protected by copyright. All rights reserved.

Hematopoietic stem cell mobilization strategies to support high-dose chemotherapy: A focus on relapsed/refractory germ cell tumors

High-dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation has been explored and has played an important role in the management of patients with high-risk germ cell tumors (GCTs) who failed to be cured by conventional chemotherapy. Hematopoietic stem cells (HSCs) collected from the peripheral blood, after appropriate pharmacologic mobilization, have largely replaced bone marrow as the principal source of HSCs in transplants. As it is currently common practice to perform tandem or multiple sequential cycles of HDCT, it is anticipated that collection of large numbers of HSCs from the peripheral blood is a prerequisite for the success of the procedure. Moreover, the CD34+ cell dose/kg of body weight infused after HDCT has proven to be a major determinant of hematopoietic engraftment, with patients who receive > 2 × 10⁶ CD34+ cells/kg having consistent, rapid, and sustained hematopoietic recovery. However, many patients with relapsed/refractory GCTs have been exposed to multiple cycles of myelosuppressive chemotherapy, which compromises the efficacy of HSC mobilization with granulocyte colony-stimulating factor with or without chemotherapy. Therefore, alternative strategies that use novel agents in combination with traditional mobilizing regimens are required. Herein, after an overview of the mechanisms of HSCs mobilization, we review the existing literature regarding studies reporting various HSC mobilization approaches in patients with relapsed/refractory GCTs, and finally report newer experimental mobilization strategies employing novel agents that have been applied in other hematologic or solid malignancies.

Does myeloma genetic have an effect on stem cell mobilization?

BACKGROUND

Autologous stem cell transplantation (ASCT) after induction treatment is the standard of care. Our understanding of myeloma genetics has been very limited and its effect to stem cell mobilization is not widely investigated. We aimed to investigate the effect of genetic abnormalities on stem cell mobilization in myeloma.

METHODS

The data of 150 MM patients who underwent stem cell mobilization at our center between 2009-2020 were included and analyzed retrospectively. Pre-treatment bone marrow cytogenetics and fluorescence in situ hybridization tests were performed for each patient.

RESULTS

Groups were divided into two as patients with normal cytogenetic and abnormal cytogenetic. No difference observed between groups regarding age, gender and ECOG (p = 0.4; p = 0.2; p = 0.3). Groups were similar concerning myeloma characteristics, received treatment and treatment response. Median CD34+ cells/kg harvested was 444(2-11.29) in normal cytogenetic group whereas it was 4,8(2.4-8.6) in abnormal cytogenetic group(p = 0.2). Optimal CD34+ cells level achievement was 73 (67 %) in normal cytogenetic group while it was 25(71.4 %) in abnormal cytogenetic group(p = 0.6). Neutrophil and platelet engraftment durations were similar among cytogenetic groups (p = 0.7; p = 0.9). R-ISS based groups were also did not differ regarding harvested CD34+ cells and achievement optimal CD34 level (p = 0.79, p = 0.74). Engraftment durations for neutrophil and platelet were comparable between R-ISS based groups (p = 0.59, p = 0.65) CONCLUSIONS: Here we were not able to find any impact of genetic abnormalities on stem cell mobilization in myeloma patients. Expanded studies can aid to identify the effect of particular genetic anomalies on the stem cell mobilization.

The Efficacy and Safety of Chemotherapy-Based Stem Cell Mobilization in Multiple Myeloma Patients Who Are Poor Responders to Induction: The Mayo Clinic Experience

We report the outcomes of 117 patients with newly diagnosed multiple myeloma who received novel agent induction, had a poor response to induction, and were mobilized using intravenous intermediate-dose cyclophosphamide (82%) or VD-PACE (18%) plus granulocyte colony-stimulating factor (G-CSF) and on-demand plerixafor. The median progression-free survival and overall survival of the chemo-mobilized cohort were 21 months (95% confidence interval [CI], 15-71) and 58 months (95% CI, 47-80), respectively. We compared our cohort to a 117-patient cohort matched by the level of response at pretransplant evaluation. The matched patients were mobilized with G-CSF and on-demand plerixafor without chemotherapy. Patients receiving chemo-mobilization had higher stem cell yields than the growth-factor-only cohort (median, 10.7 × 10⁶ cells/kg vs. 8.77 × 10⁶ cells/kg, respectively; P < .001). The safety profile of chemo-mobilization was favorable, and there was no difference between the two groups in length of hospitalization during autologous stem cell transplantation (P = .95), days to neutrophil engraftment (P = .22), days to platelet engraftment (P = .27), or risk of bacteremia (P = .52). Twenty-nine percent of the chemo-mobilized cohort and 65% of the matched cohort required plerixafor for adequate mobilization (P < .001). Chemo-mobilization enhances stem cell collection without adversely impacting the post-transplant clinical course.

Shorter Interdonation Interval Contributes to Lower Cell Counts in Subsequent Stem Cell Donations

Approximately 7% of unrelated hematopoietic stem cell donors are asked to donate stem cells a subsequent time to the same or a different recipient. Recent studies have shown that donation-related symptoms for second donations are similar to those for the first donation. Little is known about differences in stem cell mobilization and yields for subsequent peripheral blood stem cell (PBSC) and bone marrow (BM) collections. We hypothesized that CD34⁺ cell yields and total nucleated cell (TNC) concentrations for subsequent PBSC or BM donations are lower than those at the first donation. We also evaluated the factors influencing stem cell yields in healthy unrelated second-time donors. Data were gathered from the Center for International Blood and Marrow Transplant Research database on 513 PBSC and 43 BM donors who donated a second time between 2006 and 2017 through the National Marrow Donor Program. Among the second-time PBSC donors, we found significantly lower preapheresis peripheral blood CD34⁺ cell counts (68.6 × 10⁶/L versus 73.9 × 10⁶/L; P = .03), and collection yields (556 × 10⁶ versus 608 × 10⁶; P = .02) at the second donation compared to the first. This decrease at the subsequent donation was associated with a shorter interdonation interval, lower body mass index (BMI), and a lower total G-CSF dose. In most instances, suboptimal mobilizers at their first donation donated suboptimal numbers of stem cells at their subsequent donations. Among repeat BM donors, the TNC concentration was lower at the second donation. The small size of this group precluded additional analysis. Overall, when considering repeat donations, increasing the interdonation intervals and evaluating for BMI changes should be considered to optimize stem cell yields. Some of these parameters may be improved by increasing G-CSF dose in PBSC donors within permissible limits.

Low baseline platelet count predicts poor response to plerixafor in patients with multiple myeloma undergoing autologous stem cell mobilization

BACKGROUND AIMS

Baseline platelet count has been shown to be a sensitive predictor of autologous peripheral blood progenitor cell collection yield in patients with multiple myeloma mobilized with granulocyte colony-stimulating factor (G-CSF). Patients who mobilize poorly with G-CSF are often treated with plerixafor to enhance mobilization. There are no surrogate markers available to predict response to plerixafor.

METHODS

We retrospectively analyzed data from 73 patients with multiple myeloma who did not have adequate mobilization with G-CSF alone and were treated with plerixafor as a rescue agent.

RESULTS

We found that baseline platelet count directly correlated with peripheral blood CD34⁺ (PB-CD34⁺) count after plerixafor treatment (r = 0.36, P < 0.0001) and the number of PB-CD34⁺ cells collected on the first day of apheresis and inversely correlated with the number of apheresis sessions needed to collect the target number of PB-CD34⁺ cells (P = 0.0015). Baseline platelet count of 153 000/µL or less was associated with 90% specificity of predicting poor response to plerixafor with a sensitivity of 33%.

CONCLUSIONS

Baseline platelet count is a good predictor of mobilization response to plerixafor in patients with multiple myeloma.

Autologous hematopoietic progenitor cell mobilization and collection in adult patients presenting with multiple myeloma and lymphoma: A position-statement from the Turkish Society of Apheresis (TSA)

Autologous hematopoietic cell transplantation (AHCT) is a routinely used procedure in the treatment of adult patients presenting with multiple myeloma (MM), Hodgkin lymphoma (HL) and various subtypes of non-Hodgkin lymphoma (NHL) in upfront and relapsed/refractory settings. Successful hematopoietic progenitor cell mobilization (HPCM) and collection are the rate limiting first steps for application of AHCT. In 2015, almost 1700 AHCT procedures have been performed for MM, HL and NHL in Turkey. Although there are recently published consensus guidelines addressing critical issues regarding autologous HPCM, there is a tremendous heterogeneity in terms of mobilization strategies of transplant centers across the world. In order to pave the way to a more standardized HPCM approach in Turkey, Turkish Society of Apheresis (TSA) assembled a working group consisting of experts in the field. Here we report the position statement of TSA regarding autologous HPCM mobilization strategies in adult patients presenting with MM and lymphoma.

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.

Mobilization of hematopoietic progenitor cells for autologous transportation: consensus recommendations

Selected patients with certain hematological malignancies and solid tumors have the potential to achieve long-term survival with autologous hematopoietic progenitor cell transplant. The collection of these cells in peripheral blood avoids multiple bone marrow aspirations, results in faster engraftment and allows treatment of patients with infection, fibrosis, or bone marrow hypocellularity. However, for the procedure to be successful, it is essential to mobilize a sufficient number of progenitor cells from the bone marrow into the blood circulation. Therefore, a group of Brazilian experts met in order to develop recommendations for mobilization strategies adapted to the reality of the Brazilian national health system, which could help minimize the risk of failure, reduce toxicity and improve the allocation of financial resources.

Upfront use of plerixafor and granulocyte-colony stimulating factor (GCSF) for stem cell mobilization in patients with multiple myeloma: efficacy and analysis of risk factors associated with poor stem cell collection efficiency

Plerixafor (P), an agent that selectively and reversibly binds to the chemokine receptor CXCR4, has been approved in combination with G-CSF (P + G-CSF) for stem cell (SC) mobilization in patients with multiple myeloma (MM). The goal of this study was to determine the SC collection success rate of P + G-CSF using a clinically relevant outcome defined as the ability to collect at least 5 × 10⁶ CD34⁺ cells/kg to allow safely two transplants, and identify risk factors impacting SC mobilization. One hundred and thirty-eight patients were mobilized with P + G-CSF upfront following induction. The SC collection success rate was 92.8%. We identified exposure to lenalidomide alone (p = .038), WBC count <4 × 10³/mcL prior to mobilization (p = .01) and non-African American race (p = .019), as risk factors for low efficiency by multivariate analysis. This study demonstrates that P + G-CSF is highly efficient in MM patients and provides strong support for its upfront use in SC collection for MM patients.

How do we mobilize and collect autologous peripheral blood stem cells?

Autologous stem cell transplantation (ASCT) with mobilized peripheral blood stem cells (PBSCs) has become a widely applied therapeutic approach for many hematologic and nonhematologic diseases. Adequate PBSC mobilization is critical to the success of ASCT. However, many factors can contribute to poor mobilization. Plerixafor is an effective yet costly adjunct agent that has been increasingly used to improve mobilization in a variety of diagnoses and clinical settings. However, to achieve both optimal cell collection yields and cost-effectiveness, the role of plerixafor in PBSC mobilization needs to be well defined in terms of triggers for initiating its use and criteria for monitoring response. As one of the largest hematopoietic transplant centers in the country, we have developed an approach to PBSC mobilization and collection that incorporates patient laboratory assessments, monitoring of the collection yields, and judicious use of plerixafor as well as various patient support and education programs. These measures have resulted in an increase in our collection success rate and a decrease in the mean number of collection days. In this article we describe our approach to autologous PBSC mobilization and collection. Pertinent reports in the literature are also reviewed and discussed.

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.

Decision-tree algorithm for optimized hematopoietic progenitor cell-based predictions in peripheral blood stem cell mobilization

BACKGROUND

Enumerating hematopoietic progenitor cells (HPCs) by using an automated hematology analyzer is a rapid, inexpensive, and simple method for predicting a successful harvest compared with enumerating circulating CD34+ cells. However, the optimal HPC cutoff count and the indicating factors to be considered for improved predicting have not yet been determined.

STUDY DESIGN AND METHODS

Between 2007 and 2012, a total of 189 consecutive patients who proceeded to peripheral blood stem cell (PBSC) harvesting were retrospectively recruited. Baseline characteristics were analyzed to identify the risk factors for a failed harvest, which were defined as less than 2 × 10(6) CD34+ cells/kg. Variables identified by multivariate logistic regression and correlation analysis for predicting a successful harvest were subjected to classification and regression tree (CART) analysis.

RESULTS

PBSCs were successfully harvested in 154 (81.5%) patients. An age of at least 60 years, a diagnosis of a solid tumor, at least five prior chemotherapy cycles, prior radiotherapy, and mobilization with granulocyte-colony-stimulating factor alone or high-dose cyclophosphamide were independent baseline predictors of poor mobilization. In CART analysis, patients with zero to two host risk factors and either higher HPC (≥28 × 10(6) /L) or mononuclear cell (MNC; ≥3.5 × 10(9) /L) counts were categorized as good mobilizers and their harvest success rate was 92.3%. By contrast, 30.3% of harvests were adequate in the patients with three to five host risk factors and lower HPC and MNC counts.

CONCLUSION

A CART algorithm incorporating host predictors and HPC and MNC counts improves predictions in a successful harvest and might reduce the necessity of monitoring peripheral CD34+ cells.

Circulating hematopoietic progenitors and CD34(+) cells predicted successful hematopoietic stem cell harvest in myeloma and lymphoma patients: experiences from a single institution

Background

Previous studies have shown that the numbers of both circulating hematopoietic progenitor cell (HPC) and CD34⁺ cell are positively correlated with CD34⁺ cell harvest yield. However, the minimal numbers of both circulating HPCs and CD34⁺ cells required for performing an efficient hematopoietic stem cell (HSC) harvest in lymphoma and myeloma patients have not been defined in our institution.

Patients and methods

Medical records of 50 lymphoma and myeloma patients undergoing peripheral blood HSC harvest in our institution were retrospectively reviewed. The minimal and optimal HSC harvest yield required for the treatment was considered to be ≥2×10⁶ CD34⁺ cells/kg and ≥5×10⁶ CD34⁺ cells/kg, respectively.

Results

The minimally required or optimal HSC yield obtained was not influenced by age (≥60 years), sex, underlying malignancies, disease status, multiple rounds of chemotherapy, or history of radiotherapy. The numbers of both circulating HPC and CD34⁺ cell were higher in patients with minimally required HSC yields (P=0.000 for HPC and P=0.000 for CD34⁺ cell) and also in patients with optimal HSC yields (P=0.011 for HPC and P=0.006 for CD34⁺ cell). The cell count cutoff for obtaining minimally required HSC harvest was determined to be 20/mm³ for HPCs and 10/mm³ for CD34⁺ cells. Furthermore, the cell count cutoff for obtaining optimal HSC harvest was determined to be 60/mm³ for HPCs and 35/mm³ for CD34⁺ cells.

Conclusion

A total of 60/mm³ of HPCs and 35/mm³ of CD34⁺ cells in peripheral blood predicted optimal HSC harvest in lymphoma and myeloma patients.

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.

Predicting poor peripheral blood stem cell collection in patients with multiple myeloma receiving pre-transplant induction therapy with novel agents and mobilized with cyclophosphamide plus granulocyte-colony stimulating factor: results from a Gruppo Italiano Malattie EMatologiche dell'Adulto Multiple Myeloma Working Party study

INTRODUCTION

A still not well defined proportion of patients with multiple myeloma (MM) and eligible for autologous stem cell transplantation (AuSCT) fails to mobilize CD34+ peripheral blood stem cells (PBSC) at all or to collect an adequate number for a safe procedure or sufficient for multiple transplants. These so-called "poor-mobilizers" are difficult to be predicted, due to marked difference across previous heterogeneous studies.

METHODS

We aimed to develop a method based on simple clinical parameters for predicting unsuccessful (<2×10(6)/kg) or sub-optimal (<5×10(6)/kg) collections of CD34+ PBSC in newly diagnosed MM patients eligible for AuSCT, treated with novel agents and receiving an homogeneous mobilizing therapy with cyclophosphamide and granulocyte-colony stimulating factor (G-CSF). To this purpose, 1,348 patients enrolled in five consecutive Italian clinical trials were retrospectively analysed. Age, baseline low peripheral blood cell counts, use of lenalidomide, and haematological toxicity developed during induction were taken into account as possible factors associated with poor mobilization.

RESULTS

Overall, 280 patients (20.8%) showed either sub-optimal (167 patients, 12.4%) or unsuccessful (113 patients, 8.4%) collections. All analysed parameters negatively influenced the procedure, but only age and haematological toxicity during induction maintained their significance at multivariate analysis. Based on ordinal logistic regression model, we constructed a risk heat-map where the four parameters were pooled and weighted according to their relevance as single or combined variables. This model was predictive for different probabilities of failure, suboptimal or optimal outcomes.

CONCLUSIONS

We found that about one fifth of newly diagnosed MM fails to collect an adequate number of PBSC. Our model, based on a large group of patients treated frontline with novel agents and receiving the most popular mobilizing approach currently employed in Europe, is applicable in individual subjects and may contribute to the early identification of "poor mobilizer" phenotypes.

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.

Efficacy of vinorelbine plus granulocyte colony-stimulation factor for CD34+ hematopoietic progenitor cell mobilization in patients with multiple myeloma

We aimed to assess the efficacy of vinorelbine plus granulocyte colony-stimulating factor (G-CSF) for chemo-mobilization of CD34(+) hematopoietic progenitor cells (HPC) in patients with multiple myeloma and to identify adverse risk factors for successful mobilization. Vinorelbine 35 mg/m(2) was administered intravenously on day 1 in an outpatient setting. Filgrastim 5 μg/kg body weight (BW) was given twice daily subcutaneously from day 4 until the end of the collection procedure. Leukapheresis was scheduled to start on day 8 and be performed for a maximum of 3 consecutive days until at least 4 × 10(6) CD34(+) cells per kg BW were collected. Overall, 223 patients were mobilized and 221 (99%) patients proceeded to leukapheresis. Three (1.5%) patients required an unscheduled hospitalization after chemo-mobilization because of neutropenic fever and renal failure (n = 1), severe bone pain (n = 1), and abdominal pain with constipation (n = 1). In 211 (95%) patients, the leukaphereses were started as planned at day 8, whereas in 8 (3%) patients the procedure was postponed to day 9 and in 2 (1%) patients to day 10. In the great majority of patients (77%), the predefined amount of HPC could be collected with 1 leukapheresis. Forty-four (20%) patients needed a second leukapheresis, whereas only 6 (3%) patients required a third leukapheresis procedure. The median number of CD34(+) cells collected was 6.56 × 10(6) (range, .18 to 25.9 × 10(6)) per kg BW at the first day of leukapheresis and 7.65 × 10(6) (range, .18 to 25.9 × 10(6)) per kg BW in total. HPC collection was successful in 212 (95%) patients after a maximum of 3 leukaphereses. Patient age (P = .02) and prior exposition to lenalidomide (P < .001) were independent risk factors for a lower HPC amount collected in multiple regression analysis. Vinorelbine plus G-CSF enables a very reliable prediction of the timing of leukapheresis and results in successful HPC collection in 95% of the patients.

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.

Hematopoietic stem cell transplantation in older persons: respecting the heterogeneity of age

Demographic trends establish that older adults are the fastest growing segment of population, with over 19% of the population expected to be aged >65 years by 2030. As the risk for hematologic malignancies increases with age, it is imperative that our field continues to strive to individualize and manage risk and benefit in an aging population. While hematologic diseases are more common in the elderly, only a small minority of patients with hematological malignancy aged >65 years receive allogeneic hematopoietic cell transplantation, relative to the burden of disease in this population. In this editorial we explore some of the obstacles to transplantation, the rationale to consider the procedure in the older adult and ways that the stem cell consultative process can be individualized. Finally, we outline key areas where additional research is needed.