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

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.

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.

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.

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

Autologous stem cell transplantation as a frontline treatment for patients with multiple myeloma (MM) requires an adequate peripheral blood stem cell (PBSC) collection before processing. Granulocyte-colony stimulating factor (G-CSF) with or without cyclophosphamide (CTX) is a common regimen for PBSC mobilization; their benefits and risks are controversial. To compare the efficiency, safety, and survival outcomes between the two regimens, we conducted a meta-analysis including 18 studies with 4 prospective and 14 retrospective studies; a total of 2770 patients with MM were analyzed. The CTX plus G-CSF regimen had higher yields of total CD34⁺ cells (SMD = 0.39, 95% CI (0.30, 0.49)), and higher mobilization rates of the target ⩾ 2 × 10⁶/kg (OR = 3.34, 95% CI (1.82, 6.11)) and 4 × 10⁶/kg (OR = 2.16, 95% CI (1.69, 2.76)) cells. A favorable event-free survival (EFS) (HR = 0.73, 95% CI (0.58, 0.93), p = 0.01) and better 3-year EFS rate (OR = 1.65, 95% CI (1.1, 2.47), p = 0.02) were also reached in the patients with CTX plus G-CSF mobilization, although the risks of admission (OR = 26.49, 95% CI (7.31, 95.97)) and fever (OR = 13.66, 95% CI (6.21, 30.03)) during mobilization were increased, the treatment-related mortality was consistent (p = 0.26). The CTX plus G-CSF regimen was superior to the G-CSF-alone regimen for PBSC mobilization in patients with MM.

Medical database analysis of japanese multiple myeloma patients with planned stem cell transplantation (MEDALIST) - a focus on healthcare resource utilization and cost

This study explored the burden associated with stem cell mobilization, with or without cyclophosphamide (CPA), in patients who intended to receive autologous stem cell transplantation (ASCT) for multiple myeloma (MM). A Japanese health care claims database (MDV) was used to analyze the health care resource utilization patterns and medical cost between 2013 and 2016 (pre-plerixafor launch). The patients were further categorized into groups who received granulocyte-colony stimulating factor (G-CSF) alone or G-CSF + CPA group and analyzed in both mobilization and ASCT phases of treatment. Overall, there were more MM patients who were treated with G-CSF + CPA combination therapy than G-CSF alone. Length-of-stay was 1.6 times longer in the combination group during the mobilization phase. A reverse trend was observed during the ASCT phase. Direct cost was approximately 1.2 million yen during the mobilization phase and 2.3 million yen during the ASCT phase, with hospitalization basic fee accounting for the highest proportion in both groups and phases. A substantial amount of healthcare resource and cost was consumed in both phases. This study may serve as a basic reference for further health technology assessment of new medicines such as plerixafor. Further investigation of differences between treatment groups is warranted.

Risk of secondary primary malignancies in multiple myeloma patients with or without autologous stem cell transplantation

Outcomes for patients with multiple myeloma (MM) have improved through use of novel treatments, especially lenalidomide combined with autologous stem cell transplantation. However, because of their increased life expectancy, an increased risk of secondary primary malignancies (SPMs) has been observed in MM patients, particularly after lenalidomide maintenance in both transplant-eligible (TE) and transplant-ineligible (TI) patients. To evaluate the incidence and risk factors of developing SPMs, we identified 17 TE-MM and 12 TI-MM patients with SPMs among 211 TE-MM and 280 TI-MM patients, including seven TE-MM and four TI-MM patients with hematological malignancies and ten TE-MM and eight TI-MM patients with non-hematological cancers, respectively. The median follow-up time from diagnosis was > 4 years. Multivariate analysis identified a history of high-dose cyclophosphamide use for peripheral blood stem cell harvest in TE-MM patients and > 65 years of age at diagnosis, or a history of adriamycin, lenalidomide, or thalidomide use in TI-MM patients as independent risk factors for SPMs (P < 0.001). Patients with a history of lenalidomide use had a lower risk of death among both TE-MM (P = 0.0326) and TI-MM (P < 0.001) patients. The survival benefit of receiving lenalidomide outweighed the increased risk of SPMs in both TE-and TI-MM patients.