Stem cell mobilization in multiple myeloma patients: Do we need an age-adjusted regimen for the elderly?

Improved Prediction of CD34+ Cell Yield before Peripheral Blood Hematopoietic Progenitor Cell Collection Using a Modified Target Value-Tailored Approach

The most commonly used stem cell source for both autologous and allogeneic transplantation is mobilized peripheral blood hematopoietic progenitor cells collected by apheresis. In the 1990s, an Italian group used the correlation between the preapheresis peripheral blood CD34+ cell count and the final number of CD34+ cells collected to devise a formula for "target value-tailored" (TVT) apheresis. Using local patient data, the Canadian Blood Services Stem Cell Laboratory created a similar model to determine the blood volume to process during apheresis collection. The objectives of this study were to determine the correlation between the number of CD34+ cells predicted by the TVT formula and the actual number of CD34+ cells collected and to determine whether the TVT formula remains predictive when applied to an external data set. All apheresis collections performed at the Ottawa Hospital between January 1, 2003 and October 2, 2013 were reviewed. The primary outcome was the correlation between the number of CD34+ cells predicted by the TVT formula and the actual number of CD34+ cells collected on day 1 of apheresis. For the external data set, all autologous collections performed at the London Health Sciences Centre between December 1, 2008 and December 1, 2013 were reviewed. The external data set was divided into test and validation sets to determine whether a model could be created to predict the final number of CD34+ cells collected on day 1 based on the preapheresis CD34+ count. A total of 1252 collections were included in the analysis. The Ottawa data set included 1012 collections, 836 of which were autologous and 176 of which were from donors. Of the autologous collections in Ottawa, 764 (92.5%) were first collections. In 759 (91%) collections, chemotherapy plus granulocyte colony-stimulating factor (G-CSF) was used as the mobilization regimen. In 747 collections (89%), only 1 collection day was required to achieve the desired number of CD34+ cells. The TVT estimate was highly predictive of the number of CD34+ cells × 10(6)/kg actually collected on apheresis day 1 (r = .90, P < .0001). The London data set included 240 autologous collections. All mobilizations were with G-CSF alone. For the test set, the precollection CD34+ count was highly predictive of the number of CD34+ cells × 10(6)/kg collected on day 1 of apheresis. Applying this model to the validation set, the correlation between the predicted and final and day 1 CD34+ cells × 10(6)/kg count was .9186 (P < .0001). Using a modified TVT approach, the preapheresis CD34+ count can be used to accurately predict the number of CD34+ cells × 10(6)/kg collected on day 1. This approach can be applied at other centers and for different diseases and mobilization regimens. This method can be used to individualize the blood volume processed and, thus, optimize resource utilization.

Autologous haematopoietic cell transplantation in elderly patients with multiple myeloma

High-dose chemotherapy with melphalan followed by autologous haematopoietic cell transplantation (AHCT) is a standard of care in young patients (<65 years) with multiple myeloma. Most myeloma patients, however, are older than 65 years at the time of diagnosis, and the findings of numerous single-centre and registry studies provide evidence that AHCT can be a feasible and effective treatment option in these patients. Nevertheless, AHCT is not generally recommended as standard treatment in the elderly, due to the fact that a benefit of AHCT over conventional-dose therapy has not been demonstrated by prospective randomized trials. Yet, the use of AHCT has increased substantially in older patients in recent years, and an increasing number of reports suggest comparable outcomes for older and younger patients after AHCT. In this review we summarize the results of AHCT for elderly patients with multiple myeloma.

Multiple myeloma in the older adult: better prospects, more challenges

PURPOSE

Multiple myeloma (MM) is disproportionately diagnosed in older adults; with the aging of the population, the number of older adults diagnosed with MM will increase by nearly 80% in the next two decades. Duration of survival has improved dramatically over the last 20 years, but the improvements in older adults have not been as great as those in younger adults with MM.

METHODS

In this article, we address treatment approaches in older adults who are eligible for and those ineligible for high-dose therapy with autologous stem-cell transplantation as well as supportive care considerations and the potential role for geriatric assessment in facilitating decision making for older adults with MM.

RESULTS

The evidence from recent studies demonstrates that combinations of novel and conventional antimyeloma agents result in improved response rates and, in some cases, improved progression-free and overall survival. However, some older adults are particularly vulnerable to toxicities of therapy and discontinuation of therapy and, consequently, they have poorer survival. In addition, older adults may prioritize other outcomes of therapy, such as quality of life, over more conventional end points such as disease response and duration of survival. Geriatric assessment can facilitate risk-stratification of older adults at greater risk for adverse events from therapy and aid in personalizing therapy for vulnerable or frail older adults.

CONCLUSION

Survival in older adults with MM is improving with novel therapeutics, but efficacy must be balanced with risk of toxicity of therapy and maintenance of quality of life. Novel instruments such as geriatric assessment tools may facilitate these aims.

A plerixafor-based strategy allows adequate hematopoietic stem cell collection in poor mobilizers: results from the Canadian Special Access Program

Plerixafor effectively mobilizes hematopoietic stem cells (HSCs). However, most patients' cells are successfully collected using traditional strategies and there is limited cost-effectiveness data. The objectives of this study were to: (1) summarize the published reports of mobilization using a plerixafor-based strategy during compassionate access programs and (2) describe the Canadian experience with plerixafor during its availability by Health Canada's Special Access Program. A literature search identified reports of plerixafor-based mobilization during compassionate access programs. Overall, successful collection of at least 2 × 10(6) CD34+ cells/kg was achieved in ~75% of patients, and about two-thirds of patients went on to HSCT. A greater proportion of patients had successful collections when plerixafor was used in the upfront or preemptive settings. Plerixafor was made available by Health Canada's SAP from September 2008 to December 2010. In 96 of 132 (73%) patients, there was successful collection of at least 2 × 10(6) CD34+ cells/kg. Ninety-nine (75%) patients went on to receive an autologous transplant. Plerixafor-based mobilization is effective in perceived poor mobilizers. The optimal way to incorporate plerixafor into a mobilization strategy, however, remains to be determined. Centre-specific analysis of resource utilization may help to identify the most cost-effective way to implement various plerixafor-based mobilization strategies.

Safety and efficacy of upfront plerixafor + G-CSF versus placebo + G-CSF for mobilization of CD34(+) hematopoietic progenitor cells in patients ≥60 and <60 years of age with non-Hodgkin's lymphoma or multiple myeloma

The efficacy and safety of plerixafor + G-CSF in enhancing hematopoietic stem cell mobilization and collection has been demonstrated in two phase III studies involving patients with NHL or MM. In these pivotal studies, plerixafor + G-CSF significantly increased the proportion of patients achieving target stem cell yields, compared to placebo + G-CSF. In this analysis, we compare the efficacy and safety of plerixafor + G-CSF versus placebo + G-CSF in patients enrolled in the two phase III studies, stratified by age: ≥60 years of age and <60 years of age. The proportion of older patients who achieved target stem cell yields was significantly higher in the plerixafor group than in placebo group (NHL: 50.9 vs. 25.4%, P < 0.001; MM: 69.6 vs. 23.7%, P < 0.001). In this older cohort, the median times to neutrophil and to platelet engraftment following autologous stem cell transplant were comparable between the plerixafor and placebo groups. Similar efficacy findings were observed in the younger age group. The most common adverse events (all grades) reported among older patients in the plerixafor group included diarrhea (41.3%), nausea (38.9%), fatigue (30.2%), and injection-site reaction (29.4%). The frequency of adverse events was similar between the older and the younger age groups. Taken together, our subanalysis demonstrate that plerixafor + G-CSF can be safely and effectively used in adult patients of all ages, including those ≥60 years, to support optimal stem cell mobilization for autologous stem cell transplantation.

Risk factors for unsuccessful peripheral blood stem cell harvesting using granulocyte-colony stimulating factor mobilization in patients with multiple myeloma

The aim of this study was to determine factors that influence unsuccessful peripheral blood stem cell (PBSC) harvesting in patients with multiple myeloma (MM). Retrospective data of 186 MM patients who received G-CSF as mobilization were analyzed. Patients with successful harvest were compared with those who failed (using 2 definitions of failure <2 and <4 CD34 cells×10(6)/mm(3)). The groups were compared regarding age, gender, body weight, baseline platelet count, receipt of radiotherapy, number of prior chemotherapy regimens, PBSC count before collection, processed and collected volume, collect replace, number of sessions and final number of PBSC collected. By multivariate analysis, a baseline platelet count <161,000 cells/mm(3) was associated with PBSC harvest lower than 2×10(6)/kg, and age >58 years was related to PBSC harvest lower than 4×10(6)/kg CD34 cells/kg. Patients with these parameters should not receive mobilization protocols with G-CSF alone. Alternative protocols should be tested in this high risk harvest failure population.

Age at transplantation and outcome after autologous stem cell transplantation in elderly patients with multiple myeloma

BACKGROUND AND OBJECTIVE

The optimal treatment of patients with multiple myeloma (MM) is not well defined, in part because these patients are underrepresented in clinical studies. Autologous stem cell transplantation (auto-SCT) after high-dose melphalan chemotherapy can result in a prolonged response duration and survival in patients under 65 years of age.

DESIGN AND SETTING

Single-center, retrospective study of patients treated at Paoli-Calmettes Institute Cancer Centre, between January 1994 and January 2007 (96 months)

PATIENTS AND METHODS

We compared the outcome of elderly (age >65 years) patients with younger patients aged between 60 and 65 years with MM.

RESULTS

We compared 82 elderly patients with 104 younger patients. Except for age, both groups had comparable demographic features, disease characteristics, and prognostic factors. Induction VAD chemotherapy was comparable between the elderly (87%) and younger (94%) group. Prior to auto-SCT, the calculated hematopoietic cell transplantation-specific co-morbidity index was also comparable. With a median follow-up of 41 months (range, 5-227 months) after auto-SCT, 120 patients were still alive. Disease progression (n=40; 61%) was the main cause of death, and it was comparable in the two groups. Auto-SCT-related mortality was 3.8% (n=4/104) in younger and 3.7% (n=3/82) in older patients. Comparing younger/older subjects, progression-free survival was significantly higher in the younger group (P<.0001). However, disease response rates after the first auto-SCT was comparable and overall survival (OS) was also comparable (57% vs. 54% at 5 years, P=NS; 32% vs. 24% at 10 years, P=NS). In a Cox multivariate analysis model, none of the relevant characteristics was shown to be a critical prognostic feature for OS.

CONCLUSIONS

Age was insignificant for both OS and transplant-related mortality. We conclude that there is no biological justification for an age-discriminate policy for MM therapy. Physiologic aging is likely more important than chronologic aging.

Increased mobilization and yield of stem cells using plerixafor in combination with granulocyte-colony stimulating factor for the treatment of non-Hodgkin's lymphoma and multiple myeloma

Multiple myeloma and non-Hodgkin’s lymphoma remain the most common indications for high-dose chemotherapy and autologous peripheral blood stem cell rescue. While a CD34+ cell dose of 1 × 10⁶/kg is considered the minimum required for engraftment, higher CD34+ doses correlate with improved outcome. Numerous studies, however, support targeting a minimum CD34+ cell dose of 2.0 × 10⁶/kg, and an “optimal” dose of 4 to 6 × 10⁶/kg for a single transplant. Unfortunately, up to 40% of patients fail to mobilize an optimal CD34+ cell dose using myeloid growth factors alone. Plerixafor is a novel reversible inhibitor of CXCR4 that significantly increases the mobilization and collection of higher numbers of hematopoietic progenitor cells. Two randomized multi-center clinical trials in patients with non-Hodgkin’s lymphoma and multiple myeloma have demonstrated that the addition of plerixafor to granulocyte-colony stimulating factor increases the mobilization and yield of CD34+ cells in fewer apheresis days, which results in durable engraftment. This review summarizes the pharmacology and evidence for the clinical efficacy of plerixafor in mobilizing hematopoietic stem and progenitor cells, and discusses potential ways to utilize plerixafor in a cost-effective manner in patients with these diseases.

Current status of stem cell mobilization

New advances in effective mobilization of peripheral blood stem cells have permitted a greater proportion of patients to benefit from autologous stem cell transplantation. In this review, the relative merits of peripheral blood and mobilized bone marrow are discussed. All available agents are reviewed. A critical assessment of the appropriate dosing and frequency of available growth factors is undertaken, and the most commonly used chemotherapy plus growth factor combinations are covered. Specific recommendations for patients who are poor mobilizers are dealt with including the role of plerixafor.

Peripheral blood stem cell collection in elderly patients

Intensive treatments like autologous blood stem cell transplantations are standard consolidation treatments for lymphoma and myeloma in young people. The upper age limit for these procedures is constantly increasing. Instead of studying the impact of aging on harvesting peripheral blood stem cells (PBSC), we performed a retrospective study to explore the feasibility of collecting stem cells from patients older than 65 years and compared the efficacy to harvest in younger patients. During a period of 7 years, we identified 108 patients with myeloma or lymphoma who were older than 65 years who underwent PBSC collection. Only eight patients failed to produce a successful harvest. The majority of patients only needed one apheresis (71%). There was a median number of 5.3 x 10(6) CD34+ cells/kg. Our study demonstrated that older patients can also undergo PBSC harvests similar to younger patients.

The adverse prognostic impact of advanced age in multiple myeloma

The adverse prognostic impact of advanced age in multiple myeloma is multi-factorial. In this review we explore the various contributory factors to this phenomenon. These include general biological and psychosocial factors, which impact on cancer in the elderly population such as the presence of multiple co morbidities and poor performance status at diagnosis and variation in patient's expectations of treatment. Factors specific to myeloma include the ability to deliver optimum therapy in older patients and the impact of this on disease response, possible biological differences of myeloma in older patients, and how these various factors impact on the efficacy of conventional-dose, high-dose (HDT) and newer disease modifying therapies. Selected elderly patients can gain equal benefit to younger patients from effective therapies such as HDT. However, the use of specific assessment tools for the elderly, apart from chronological age, should be used to select elderly patients who will benefit. Future testing of newer therapies in patients with myeloma must include older patients, who will make up an increasing proportion of the myeloma population in the future and should incorporate assessment of effect of these therapies on quality of life.

Capture and enrichment of CD34-positive haematopoietic stem and progenitor cells from blood circulation using P-selectin in an implantable device

Clinical infusion of haematopoietic stem and progenitor cells (HSPCs) is vital for restoration of haematopoietic function in many cancer patients. Previously, we have demonstrated an ability to mimic physiological cell trafficking in order to capture CD34-positive (CD34+) HSPCs using monolayers of the cell adhesion protein P-selectin in flow chambers. The current study aimed to determine if HSPCs could be captured directly from circulating blood in vivo. Vascular shunt prototypes, coated internally with P-selectin, were inserted into the femoral artery of rats. Blood flow through the cell capture device resulted in a wall shear stress of 4-6 dynes/cm(2). After 1-h blood perfusion, immunofluorescence microscopy and flow cytometric analysis revealed successful capture of mononuclear cells positive for the HSPC surface marker CD34. Purity of captured CD34+ cells showed sevenfold enrichment over levels found in whole blood, with an average purity of 28%. Robust cell capture and HSPC enrichment were also demonstrated in devices that were implanted in a closed-loop arterio-venous shunt conformation for 2 h. Adherent cells were viable in culture and able to differentiate into burst-forming units. This study demonstrated an ability to mimic the physiological arrest of HSPCs from blood in an implantable device and may represent a practical alternative for adult stem cell capture and enrichment.

Autologous stem cell transplantation in the elderly including pre- and post-treatment options

Multiple myeloma (MM) is a disease of the elderly with a median age at diagnosis of 67 years in a referral population. High-dose chemotherapy (HDT) and autologous stem cell transplantation has been shown to improve survival in patients with MM in randomized trials and remains the preferred option for eligible patients. However, the randomized clinical trials demonstrating an advantage for HDT included only patients younger than 65 years and evidence supporting its role for the elderly patients has been based on retrospective reviews. The introduction of thalidomide, lenalidomide and bortezomib has changed the paradigm for treatment of myeloma and improved the outcome for these patients. Several ongoing clinical trials are evaluating the role of these novel agents in this population, specifically comparing these to HDT-based approaches. Other trials are examining the role of maintenance therapy post-HDT with these novel drugs with or without steroids. The role of HDT will be further redefined in the coming years with improvements in other therapies.

The treatment of the elderly multiple myeloma patients

Multiple myeloma (MM) is an incurable malignancy of the plasma cells. Most patients are diagnosed when they are older than 65 years. Therapeutic options include chemotherapy, using either established (e.g. melphalan) or newly available (e.g. thalidomide) drugs and high-dose treatment with stem-cell support (autologous as well as allogeneic). Recent research has focused on defining the target population for the different therapeutic approaches, taking into account pre-treatment characteristics of patients, particularly age, and aims to balance treatment benefit with potential adverse events. In this review we present the data available on the most recent trials dealing with the treatment of elderly MM patients.

Age has no influence on mobilization of peripheral blood stem cells in acute myeloid leukemia

The upper age limit for autologous stem cell transplantation (ASCT) in acute myeloid leukemia (AML) is increasing and peripheral blood (PB) represents the standard source of stem cell (SC). However, no data are available on the impact of age on SC mobilization in AML. We analyzed a cohort of 150 consecutive AML patients in first complete remission in order to make a comparison between patients up to 60 years and above 60 years, by evaluating CD34+ cells mobilization into PB and the number of leukapheresis needed to collect at least one single SC graft. The successful mobilization rate (>2 x 10(6) CD34+ cells/kg) was comparable between the two groups (87% vs. 80%, p = 0.29). In addition, no statistically significant difference was found in terms of either median number of CD34+ cells collected (p = 0.54) or CD34+ cells peak in PB (p = 0.70). Both groups of patients needed a median of two apheresis and no difference was found in the median number of CD34+ cells collected per single apheresis (p = 0.67). Finally, no correlation was found between age and total number of CD34+ cells collected (r = 0.003, p = 0.58). We conclude that age has no impact on mobilization of PBSCs in AML.

Autologous transplantation in elderly patients with multiple myeloma: are we asking the right questions?

Multiple myeloma is a disease of the elderly. Survival outcomes remain unacceptably low in older adults with multiple myeloma. To date, no obvious difference in tumor biology has been elucidated to explain the survival disparity between older and younger patients. Multiple factors including comorbidity, performance status, decreased physiologic reserve and potentially undertreatment contribute to poor outcomes in elderly patients with multiple myeloma. High-dose chemotherapy with autologous stem cell transplantation (ASCT) is increasingly being used to treat elderly patients with multiple myeloma in an effort to improve survival outcomes. Recent case comparison studies, and preliminary transplant registry data suggest that selected older patients can be treated with high-dose chemotherapy effectively with similar toxicity and survival benefits compared to younger patients. Traditional upper age limits for autologous transplantation are being challenged along with the definition of 'elderly' itself. Ultimately, the role of high-dose chemotherapy with stem cell rescue in the upfront treatment of older adults with multiple myeloma can only be established by prospective randomized trials. In the process of designing studies to investigate the use of ASCT in older patients, multiple issues unique to the elderly population will need to be considered. First, it will be critical to develop and validate patient selection algorithms that incorporate measures of comorbidity, cognitive function, physiologic reserve and psychosocial function to identify patients most likely to tolerate and benefit from ASCT. Second, preparative and conditioning regimens will need to be further tailored to maximize the benefit to risk ratio. Finally, outcome measures in clinical trials should include disability and quality of life measures, which may be equally important in making treatment decisions for older patients. The future application and study of autologous transplantation in older patients with multiple myeloma provides a unique opportunity to challenge ageism and serve as a model for development of tailored assessments and interventions in this population.

Vinorelbine plus intermediate dose cyclophosphamide is an effective and safe regimen for the mobilization of peripheral blood stem cells in patients with multiple myeloma

High dose cyclophosphamide (HD-Cy) is commonly used to mobilize stem cells in multiple myeloma (MM). However, timing of collection is variable and incidence of side effects is substantial. We evaluated a combination of vinorelbine (VNB) (25 mg/m(2) day 1) plus Cy (1.5 g/m(2) day 2) and G-CSF as mobilizing regimen in 37 patients with MM. Results were compared to those achieved in 41 previously diagnosed patients mobilized with Cy at 4 g/m(2). Overall, 36/37 patients receiving VNB-Cy (97%) mobilized, as opposed to 40/41 (97%) in the controls (p:0.51). Median CD34+ cells peak was 94/mul for VNB-Cy patients and 96 for controls, p=0.36; median number of CD34+ cells collected was 9.2x10(6)/kg and 8.7x10(6)/kg, respectively (p=0.85). Median number of days to the highest CD34 count was shorter for VNB-Cy patients (nine vs 11, p=0.001). No VNB-Cy patient experienced grade 3-4 neutropenia and thrombocytopenia, as opposed to 63 and 19% in the controls (p=0.001 and 0.01, respectively). Hospitalization from toxicity was never required in VNB-Cy patients as compared to 19% in control group (p=0.01). We conclude that an outpatient combination of VNB plus intermediate dose Cy plus G-CSF is a safe, predictable, and highly effective mobilization regimen for patients with newly-diagnosed MM.