Comparison of the efficiency, safety, and survival outcomes in two stem cell mobilization regimens with cyclophosphamide plus G-CSF or G-CSF alone in multiple myeloma: a meta-analysis

First Line Treatment of Newly Diagnosed Transplant Eligible Multiple Myeloma Recommendations From a Canadian Consensus Guideline Consortium

The availability of effective therapies for multiple myeloma (MM) has sparked debate on the role of first line autologous stem cell transplantation (ASCT), particularly in standard-risk patients. However, treatment for individuals with high-risk disease continues to display suboptimal outcomes. With novel therapies used earlier, practice is changing rapidly in the field of MM. Presently, quadruplet induction therapy incorporating an anti-CD38 monoclonal antibody to a proteasome inhibitor and an immunomodulatory drug prior to ASCT followed by maintenance therapy stands as the foremost strategy for attaining deep and sustained responses in transplant eligible MM (TEMM). This Canadian Consensus Guideline Consortium (CGC) proposes consensus recommendations for the first line treatment of TEMM. To address the needs of physicians and people diagnosed with MM, this document focuses on ASCT eligibility, induction therapy, mobilization and collection, conditioning, consolidation, and maintenance therapy, as well as, high-risk populations, management of adverse events, assessment of treatment response, and monitoring for disease relapse. The CGC will periodically review the recommendations herein and update as necessary.

Daratumumab during Myeloma Induction Therapy Is Associated with Impaired Stem Cell Mobilization and Prolonged Post-Transplant Hematologic Recovery

Daratumumab is being increasingly integrated into first-line multiple myeloma (MM) induction regimens, leading to improved response depth and longer progression-free survival. Autologous stem cell transplantation (ASCT) is commonly performed as a consolidation strategy following first-line induction in fit MM patients. We investigated a cohort of 155 MM patients who received ASCT after first-line induction with or without daratumumab (RVd, n = 110; D-RVd, n = 45), analyzing differences in stem cell mobilization, apheresis, and engraftment. In the D-RVd group, fewer patients successfully completed mobilization at the planned apheresis date (44% vs. 71%, p = 0.0029), and more patients required the use of rescue plerixafor (38% vs. 28%, p = 0.3052). The median count of peripheral CD34+ cells at apheresis was lower (41.37 vs. 52.19 × 106/L, p = 0.0233), and the total number of collected CD34+ cells was inferior (8.27 vs. 10.22 × 106/kg BW, p = 0.0139). The time to recovery of neutrophils and platelets was prolonged (12 vs. 11 days, p = 0.0164; and 16 vs. 14 days, p = 0.0002, respectively), and a higher frequency of erythrocyte transfusions (74% vs. 51%, p = 0.0103) and a higher number of platelet concentrates/patients were required (4 vs. 2; p = 0.001). The use of daratumumab during MM induction might negatively impact stem cell mobilization and engraftment in the context of ASCT.

Efficacy of prophylactic antibiotics for the prevention of neutropenic fever in patients with multiple myeloma receiving high-dose cyclophosphamide for stem cell mobilization

High-dose cyclophosphamide (HD-Cy) (3 g/m2) plus granulocyte colony-stimulating factor (G-CSF) is a very effective regimen for peripheral blood stem cell (PBSC) mobilization. Unfortunately, it is associated with an increased risk of neutropenic fever (NF). We analyzed the effect of NF on PBSC apheresis results and the efficacy of prophylactic antibiotics for the prevention of NF associated with HD-Cy plus G-CSF for PBSC mobilization in patients with newly diagnosed multiple myeloma (MM). First, patients were divided into NF ( +) and NF ( -) groups according to whether they suffered from NF during mobilization. Second, we divided patients into an antibiotic prophylaxis group and a nonantibiotic prophylaxis group according to whether antibiotic prophylaxis was used during the mobilization period. Our study showed that NF( +) patients (n = 44) had lower CD34 + cell dose collection (median 2.60 versus 5.34 × 106/kg, P < 0.001) and slower neutrophil engraftment and platelet engraftment (median 11 versus 10 days, P = 0.002, and median 13 versus 11 days, P = 0.043, respectively) than NF( -) patients (n = 234). Of note, the nonantibiotic prophylaxis group patients (n = 30) had a 26.7% incidence of NF. In the patients receiving antibiotic prophylaxis (n = 227), the incidence was reduced to 9.3% (P = 0.01). The antibiotic prophylaxis patients had higher CD34 + cell collection (median 5.41 versus 2.27 × 106/kg, P < 0.001) and lower hospitalization cost of mobilization ($ median 3108.02 versus 3702.39, p = 0.012). Thus, our results demonstrate that NF is associated with lower CD34 + cell collection and that antibiotic prophylaxis can reduce the incidence of NF and improve stem cell mobilization and collection outcomes, which reduces the hospitalization cost of mobilization.

Prolonged infusion time of cyclophosphamide plus granulocyte colony-stimulating factor (G-CSF) as a mobilization regimen may improve mobilization efficiency in newly diagnosed multiple myeloma patients: a single center experience

OBJECTIVES

This study aimed to clarify the effectiveness and safety of two different infusion durations of cyclophosphamide (CTX) plus granulocyte colony-stimulating factor (G-CSF) for peripheral blood stem cell mobilization in patients with newly diagnosed multiple myeloma (NDMM).

METHODS

One hundred and fifty-six consecutive NDMM patients receiving CTX plus G-CSF mobilization and autologous stem cell transplantation during the period of September 2008 to May 2020 were selected for retrospective analysis. According to differences in prolonged infusion time of CTX, they were divided into a 24-h group (24-h continuous infusion) and a control group (4-6 h of infusion). Mobilization and safety of infusion were analyzed. Flow cytometry was used to detect the peripheral blood CD34+ cell count. Multivariate analysis was performed to determine the factors influencing the number of CD34+ cells.

RESULTS

The mean CD34+ cell counts collected in 24-h and control groups were 6.78 (interquartile range [IQR] 3.59-11.69) and 4.48 (IQR 2.39-6.30) ×106/kg, respectively (p < 0.001). Meanwhile, the target number of CD34+ cells/kg (defined as ≥4 × 106/kg) was collected from 51 (75%) of cases in 24-h group vs. 45 (51%) in the control group (p = 0.002). Multivariate analysis identified the independence of CTX infusion time as a factor influencing the target number of CD34+ cells/kg [odds ratio OR, 4.045; 95% CI: 1.630-10.038, p = 0.003]. The post-transplantation time to neutrophil engraftment was 10 (IQR 9-11) in 24-h group and 11 (IQR 10-12) in control group (p < 0.001). Finally, no statistical differences were identified between groups in terms of hematologic and non-hematologic toxicities.

CONCLUSIONS

For patients with NDMM, 24-h continuous infusion of CTX plus G-CSF contributes to improved mobilization efficiency and equivalent toxicity as a stem cell mobilization regimen.

Revisiting the Role of Alkylating Agents in Multiple Myeloma: Up-to-Date Evidence and Future Perspectives

From the 1960s to the early 2000s, alkylating agents (e.g., melphalan, cyclophosphamide, and bendamustine) remained a key component of standard therapy for newly-diagnosed or relapsed/refractory multiple myeloma (MM). Later on, their associated toxicities (including second primary malignancies) and the unprecedented efficacy of novel therapies have led clinicians to increasingly consider alkylator-free approaches. Meanwhile, new alkylating agents (e.g., melflufen) and new applications of old alkylators (e.g., lymphodepletion before chimeric antigen receptor T-cell [CAR-T] therapy) have emerged in recent years. Given the expanding use of antigen-directed modalities (e.g., monoclonal antibodies, bispecific antibodies, and CAR-T therapy), this review explores the current and future role of alkylating agents in different treatment settings (e.g., induction, consolidation, stem cell mobilization, pre-transplant conditioning, salvage, bridging, and lymphodepleting chemotherapy) to ellucidate the role of alkylator-based regimens in modern-day MM management.

Stem cell mobilization in multiple myeloma: challenges, strategies, and current developments

Among hematological malignancies, multiple myeloma (MM) represents the leading indication of autologous hematopoietic stem cell transplantation (auto-HCT). Auto-HCT is predominantly performed with peripheral blood stem cells (PBSCs), and the mobilization and collection of PBSCs are essential steps for auto-HCT. Despite the improved success of conventional methods with the incorporation of novel agents for PBSC mobilization in MM, mobilization failure is still a concern. The current review comprehensively summarizes various mobilization strategies for mobilizing PBSCs in MM patients and the evolution of these strategies over time. Moreover, existing evidence substantiates that the mobilization regimen used may be an important determinant of graft content. However, limited data are available on the effects of graft characteristics in patient outcomes other than hematopoietic engraftment. In this review, we discussed the effect of graft characteristics on clinical outcomes, mobilization failure, factors predictive of poor mobilization, and potential mobilization regimens for such patients.

Stem Cell Mobilization with Ixazomib and G-CSF in Patients with Multiple Myeloma

(1) Background: High-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT) is the standard consolidation strategy for patients with newly diagnosed multiple myeloma (MM) and for a subset of patients with relapsed/refractory disease. For stem cell mobilization, G-CSF alone or in combination with chemotherapy mobilizing agents and/or plerixafor are commonly used. Ixazomib is an oral proteasome inhibitor with less neurotoxic potential, which previously showed the ability to mobilize stem cells in preclinical studies. (2) Methods: Prospective single-center phase 1 study assessing the efficacy and safety of stem cell mobilization with ixazomib and G-CSF in patients with newly diagnosed or relapsed/refractory MM undergoing HDCT and ASCT. Primary endpoint was percentage of patients achieving a yield of at least 6.0 × 10⁶/kg CD34+ cells within the first apheresis. G-CSF (filgrastim) 10 μg/kg/day was administered subcutaneously (s.c.) from day 1 to day 5 (planned apheresis) and ixazomib 4 mg orally at day 4. Plerixafor 24 mg s.c. was administered if the stem cell mobilization with ixazomib and G-CSF was not sufficient. (3) Results: 19 patients were treated within the study between 06/2020 and 02/2021. The primary endpoint was reached in 17 (89%) patients, with a median of 7.1 × 10⁶/kg CD34+ cells collected within the first apheresis, comparable to previously published results, and only 2 (11%) patients required a second apheresis. Median number of circulating CD34+ cells was 14.0 × 10⁶/L (2.0-95.2) before the administration of ixazomib, and 33.0 × 10⁶/L (4.2-177.0) pre-apheresis. However, 9 (47%) patients required the addition of plerixafor to ensure optimal stem cell collection. (4) Conclusions: The combination of ixazomib and G-CSF showed promising stem cell mobilizing activity in patients with MM prior to HDCT and ASCT. Future larger studies might further investigate the role of ixazomib in stem cell mobilization regimens for MM.

Prolonged Lenalidomide Induction Does Not Significantly Impair Stem Cell Collection in Multiple Myeloma Patients Mobilized With Cyclophosphamide or Plerixafor: A Report From The Covid Era

Introduction

Induction therapy for multiple myeloma is traditionally capped at 6 cycles of lenalidomide due to concerns that longer treatment compromises the ability to collect sufficient stem cells for autologous stem cell transplantation (ASCT). However, during the COVID-19 pandemic, many of our patients received prolonged lenalidomide induction due to concerns about proceeding to ASCT. We investigated whether prolonged induction with lenalidomide affects the efficacy of stem cell collection among patients mobilized with cyclophosphamide and/or plerixafor.

Patients and methods

This single center, retrospective study included patients who were treated with lenalidomide induction regimens, received mobilization with cyclophosphamide or plerixafor, and underwent apheresis in preparation for ASCT. 94 patients were included, 40 of whom received prolonged induction with >6 cycles of lenalidomide containing regimen.

Results

Patients who received prolonged induction were more likely to require >1 day of apheresis (38% vs. 15%; OR 3.45; P = .0154), and there was a significant correlation between the duration of lenalidomide treatment and the apheresis time required to collect sufficient cells for transplant (R² = 0.06423, P = .0148). However, there was no significant difference between patients who received prolonged induction and those who did not with respect to CD34⁺ stem cell yields at completion of apheresis (9.99 vs. 10.46 cells/Kg, P = .5513) or on the first day of collection (8.29 vs. 9.59 cells/Kg, P = .1788).

Conclusion

Among patients treated with >6 cycles of lenalidomide, mobilization augmented with cyclophosphamide and/or plerixafor will likely facilitate sufficient stem cell harvest to permit ASCT.

Efficacy of hematopoietic stem cell mobilization regimens in patients with hematological malignancies: a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

Efficient mobilization of hematopoietic stem cells (HSCs) from bone marrow niche into circulation is the key to successful collection and transplantation in patients with hematological malignancies. The efficacy of various HSCs mobilization regimens has been widely investigated, but the results are inconsistent.

METHODS

We performed comprehensive databases searching for eligible randomized controlled trials (RCTs) that comparing the efficacy of HSCs mobilization regimens in patients with hematological malignancies. Bayesian network meta-analyses were performed with WinBUGS. Standard dose of granulocyte colony-stimulating factor (G-CSF SD) was chosen as the common comparator. Estimates of relative treatment effects for other regimens were reported as mean differences (MD) or odds ratio (OR) with associated 95% credibility interval (95% CrI). The surface under the cumulative ranking curve (SUCRA) were obtained to present rank probabilities of all included regimens.

RESULTS

Databases searching and study selection identified 44 eligible RCTs, of which the mobilization results are summarized. Then we compared the efficacy of mobilization regimens separately for patients with multiple myeloma (MM) and non-Hodgkin lymphoma (NHL) by including 13 eligible trials for network meta-analysis, involving 638 patients with MM and 592 patients with NHL. For patients with MM, data are pooled from 8 trials for 6 regimens, including G-CSF in standard dose (SD) or reduced dose (RD) combined with cyclophosphamide (CY), intermediate-dose cytarabine (ID-AraC) or plerixafor. The results show that compared with G-CSF SD alone, 3 regimens including ID-AraC + G-CSF SD (MD 14.29, 95% CrI 9.99-18.53; SUCRA 1.00), G-CSF SD + Plerixafor SD (MD 4.15, 95% CrI 2.92-5.39; SUCRA 0.80), and CY + G-CSF RD (MD 1.18, 95% CrI 0.29-2.07; SUCRA 0.60) are associated with significantly increased total number of collected CD34+ cells (× 106/kg), among which ID-AraC + G-CSF SD ranked first with a probability of being best regimen of 100%. Moreover, ID-AraC + G-CSF SD and G-CSF SD + Plerixafor SD are associated with significantly higher successful rate of achieving optimal target (collecting ≥ 4-6 × 106 CD34+ cells/kg). For patients with NHL, data are pooled from 5 trials for 4 regimens, the results show that compared with G-CSF SD alone, G-CSF SD + Plerixafor SD (MD 3.62, 95% CrI 2.86-4.38; SUCRA 0.81) and G-CSF SD plus the new CXC chemokine receptor-4 (CXCR-4) antagonist YF-H-2015005 (MD 3.43, 95% CrI 2.51-4.35; SUCRA 0.69) are associated with significantly higher number of total CD34+ cells collected. These 2 regimens are also associated with significantly higher successful rate of achieving optimal target. There are no significant differences in rate of achieving optimal target between G-CSF SD + Plerixafor SD and G-CSF + YF-H-2015005.

CONCLUSIONS

In conclusion, ID-AraC plus G-CSF is associated with the highest probability of being best mobilization regimen in patients with MM. For patients with NHL, G-CSF in combination with plerixafor or YF-H-2015005 showed similar improvements in HSCs mobilization efficacy. The relative effects of other chemotherapy-based mobilization regimens still require to be determined with further investigations.

The effect of comorbidity on survival and collected CD34 + cell counts in autologous hematopoietic stem cell transplant patients

OBJECTIVE

In this study, we aimed to report the effectiveness of hematopoietic cell transplantation-specific comorbidity index (HCT-CI) and GATMO scores in predicting overall survival (OS) who underwent autologous stem cell transplantation (ASCT).

MATERIAL AND METHODS

The data of 263 MM and 204 lymphoma patients who underwent ASCT in the last 11 years were retrospectively analyzed.

RESULTS

Neutrophil engraftment time, thrombocyte engraftment time and collected CD34+ cell counts were similar in MM patients with HCT-CI>2 and HCT-CI≤2 (all p>0.05). Although the estimated median OS of MM patients with HCT-CI ≤2 tended to be higher than those with HCT-CI>2, this difference was not statistically significant (52.8 vs 45 months, p=0.172). No effect of GATMO score on CD34 + count, engraftment times and OS in MM patients was detected (p>0.05). The effect of HCT-CI score on lymphoma patients was examined, it was found that the neutrophil engraftment time was longer (p=0.039) and the number of collected CD34+ cells was lower (p=0.02) in patients with HCT-CI>2 than those with HCT-CI≤2. While the estimated median OS of lymphoma patients with HCT-CI≤2 was 51.5 months, the estimated median OS of patients with HCT-CI>2 was 9.5 months (p=0.012). When lymphoma patients were divided into four groups according to their GATMO scores, the OS of the four groups was found to be different from each other (p<0.001).

CONCLUSION

HCT-CI and GATMO scores predict OS in lymphoma patients but not MM patients.

Multiple Myeloma: Risk Adapted Use of Plerixafor for Stem Cell Mobilization Prior to Autologous Stem Cell Transplantation is Effective and Cost Efficient

BACKGROUND

We used plerixafor in 'a risk adapted approach' for stem cell mobilization for multiple myeloma (MM) patients prior to autologous stem cell transplantation (ASCT).

PATIENTS AND METHODS

Between January, 2017 and December, 2019 105 consecutive patients of MM were recruited (Study Cohort). Patients received inj G-CSF 10 µg/kg in 2 divided doses for 5 days. Day 4 peripheral blood (PB) CD34+ count was used as a guide; if count was < 20 cells/µl, patients received plerixafor. For those with ≥ 20 cells/µl apheresis was commenced on day 5. We compared their outcome with 156 MM patients transplanted between 2012 and 2016 with G-CSF mobilized PB stem cells (Control Cohort). Primary end point was to collect ≥2.0  ×  10⁶ CD34+ cells/kg (minimal harvest). Secondary end points were: no of apheresis sessions, percentage of patients with optimal stem cell harvest (≥4.0  ×  10⁶ CD34+ cells/kg) and cost analysis. An intent to treat analysis was done.

RESULT

96.2% of patients achieved ≥ 2.0  ×  10⁶ CD34+ cells/kg in the study cohort vs. 87.2% in the control cohort, P < .01. Mean apheresis sessions were 1.5 vs. 1.7 respectively, P < .014 . Optimal stem cell harvest was 29.5% vs. 16%,P = .23. Days for neutrophil engraftment (P < 0.025) and for IV antibiotics (P < .0017) were favorable for the study cohort. Incremental cost effectiveness ratio was $ 15.80/- and $ 10.56/- per 1% increase to achieve a minimal and optimal harvest.

CONCLUSION

Plerixafor in this risk adapted strategy resulted in successful mobilization, decreased time to engraftment and was cost effective.