Melphalan versus melphalan plus busulphan in conditioning to autologous stem cell transplantation for low-risk multiple myeloma

Busulfan plus melphalan versus high-dose melphalan as a conditioning regimen for autologous stem cell transplantation in multiple myeloma with high-risk features (KMM 2015)

Despite the development of effective agents for multiple myeloma (MM), the management of patients with high-risk MM (HRMM) is challenging. High-dose treatment followed by autologous stem cell transplantation (ASCT) is regarded as upfront treatment for transplant-eligible patients with HRMM. In the present study, we retrospectively investigated the efficacies of two conditioning regimens for upfront ASCT in newly diagnosed patients with MM and high-risk features: high-dose melphalan (HDMEL; 200 mg/m²) and busulfan plus melphalan (BUMEL). In total, 221 patients underwent ASCT between May 2005 and June 2021; among these 221 patients, 79 had high-risk cytogenetic abnormalities. In patients with high-risk cytogenetics, BUMEL showed a tendency toward longer overall survival (OS) and progression-free survival (PFS) compared to HDMEL (median OS; not reached vs. 53.2 months; P = 0.091, median PFS; not reached vs. 31.7 months; P = 0.062). Additionally, multivariate analysis revealed that BUMEL was significantly associated with PFS (hazard ratio = 0.37, 95% confidence interval = 0.15-0.89, P = 0.026). We compared BUMEL with HDMEL in patients with other high-risk features, such as high lactate dehydrogenase level, extramedullary disease, and poor response to frontline therapy. Notably, among patients with less than very good partial response (VGPR) to frontline therapy, median PFS was significantly longer in the BUMEL group than in the HDMEL group (55.1 vs. 17.3 months, respectively; P = 0.011). These findings indicate that BUMEL may be an effective conditioning regimen for upfront ASCT in MM patients with high-risk cytogenetics; BUMEL may be more appropriate than HDMEL for patients with less than VGPR to frontline therapy.

Busulfan and thiotepa as a conditioning regimen for autologous stem cell transplantation in patients with multiple myeloma: A study of the Korean Multiple Myeloma Working Party (KMMWP-1801 study)

Background

Autologous stem cell transplantation (ASCT) remains the standard of care for patients with newly diagnosed multiple myeloma (MM). Several attempts to improve the efficacy of conditioning regimens have been conducted in MM, but no more effective regimen than conventional high-dose melphalan has been introduced.

Objective

In this study, the efficacy and toxicity of busulfan and thiotepa (BuTT) and those of high-dose melphalan (HD-MEL) were compared retrospectively as a conditioning regimen for ASCT in patients with MM.

Study design

Included in the analysis were 114 patients who received BuTT and 114 patients who received HD-MEL treatment between March 2008 and May 2020. The BuTT regimen consisted of intravenous thiotepa 5 mg/kg once a day from days 7 to 6, followed by intravenous busulfan 3.2 mg/kg once a day from days 5 to 3. The HD-MEL conditioning regimen consisted of melphalan 100 mg/m² once a day from days 3 to 2.

Results

The overall response rate after ASCT did not differ between BuTT and HD-MEL (94.7% in BuTT vs. 97.4% in HD-MEL, p = 0.333). After a median follow-up of 47.6 months, progression-free survival (PFS) tended to be longer in the BuTT group (median PFS, 41.5 months vs. 30.3 months; hazard ratio (HR), 0.706; 95% confidence interval (CI), 0.497–1.004, p = 0.053). In the subgroup analysis of patients who did not proceed to maintenance or consolidation treatment after ASCT, the difference in PFS became more significant (median PFS, 41.5 months vs. 24.4 months; HR, 0.621; 95% CI, 0.388–0.993; p = 0.047). Additionally, the BuTT group had fewer adverse events, such as grade 3 or 4 stomatitis and diarrhea, than the HD-MEL group (stomatitis, 10.5% vs. 23.7%, p = 0.013; diarrhea, 10.5% vs. 25.4%, p = 0.005). There was no difference in the occurrence of venous-occlusive disease (2.6% in BuTT vs. 0.9% in HD-MEL, p = 0.622).

Conclusion

Our study results suggest that BuTT is an effective alternative conditioning regimen with reduced toxicity in patients with newly diagnosed MM.

Long-term outcomes of busulfan plus melphalan-based versus melphalan 200 mg/m2 conditioning regimens for autologous hematopoietic stem cell transplantation in patients with multiple myeloma: a systematic review and meta-analysis

Background

High-dose melphalan (HDMEL, 200 mg/m²) is considered as the standard conditioning regimen for autologous hematopoietic stem cell transplantation (auto-HSCT) in multiple myeloma (MM). However, whether the combination of melphalan with busulfan (BUMEL) conditioning outperforms HDMEL remains controversy. Accordingly, a systematic review and meta-analysis was carried out to compare the outcomes of HDMEL and BUMEL-based conditioning regimens in newly diagnosed MM patients having undergone auto-HSCT.

Methods

A systematic literature search was conducted in PubMed, Embase and Cochrane Library database until July 31, 2021, to identify all eligible studies comparing progression-free survival (PFS), overall survival (OS), optimal treatment response after auto-HSCT, duration of stem cell engraftment and incidence of toxic events between patients undergoing BUMEL-based and HDMEL conditioning regimens. Hazard ratio (HR), mean difference (MD) or odds ratio (OR) corresponding to 95% confidence interval (CI) were determined to estimate outcomes applying RevMan 5.4 software. Publication biases were assessed by performing Egger’s test and Begg’s test by Stata 15 software.

Results

Ten studies with a total of 2855 MM patients were covered in the current meta-analysis. The results of this study demonstrated that patients having received BUMEL-based regimen was correlated with longer PFS (HR 0.77; 95% CI 0.67~0.89, P = 0.0002) but similar OS (HR 1.08; 95% CI 0.92~1.26, P = 0.35) compared with those having received HDMEL. The differences of best treatment response after auto-HSCT and duration of neutrophil or platelet engraftment did not have statistical significance between the two groups of patients. With respect to adverse effects, the patients in BUMEL-based group were less frequently subject to gastrointestinal toxicity while the patients in HDMEL group less often experienced mucositis and infection. No significant difference was observed in hepatic toxicity between the two groups of patients.

Conclusions

In the present study, BUMEL-based conditioning was identified as a favorable regimen for a better PFS and equivalent OS as compared with HDMEL, which should be balanced against higher incidences of mucositis and infection. BUMEL-based conditioning is likely to act as an alternative strategy to more effectively improve auto-HSCT outcomes in MM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02313-z.

Intravenous busulfan and melphalan versus high-dose melphalan as a conditioning regimen for early autologous stem cell transplantation in patients with multiple myeloma: a propensity score-matched analysis

We compared the efficacy and toxicity of busulfan and melphalan (BUMEL) and those of high-dose melphalan (HDMEL) as conditioning regimens for autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM) through a propensity score-matched analysis. No significant difference in the complete response and overall response rate after ASCT was observed between BUMEL and HDMEL. After a median follow-up of 37.3 months in the BUMEL group and 50.8 months in the HDMEL group, the median progression-free survival was calculated to be 32.9 months and 25.2 months (p = 0.995). With respect to non-hematologic toxicities, infections were more frequently reported in the BUMEL group (p < 0.001). Three patients who received BUMEL developed veno-occlusive disease (VOD), and all of them recovered without administration of defibrotide. In conclusion, BUMEL is an effective alternative conditioning regimen in terms of efficacy, but attention should be paid to toxicities.

Busulfan plus melphalan versus high-dose melphalan as conditioning regimens in autologous stem cell transplantation for newly diagnosed multiple myeloma

Background

High-dose melphalan (HDMEL) represents the standard conditioning regimen before autologous stem cell transplant (ASCT) in multiple myeloma (MM), but recent updates have suggested combination of melphalan with bulsulfan (BUMEL) is also associated with favorable outcomes. We performed the current study to address the lack of comparative studies between the two conditioning regimens in Asian populations.

Methods

Using the Korean National Health Insurance and Korean Health Insurance Review and Assessment Service databases, 1,304 patients newly diagnosed with MM undergoing ASCT between January 2010 and December 2014 were identified. Patients were divided according to conditioning regimen (HDMEL vs. BUMEL), and after case matching, 428 patients undergoing HDMEL conditioning were compared to 107 patients undergoing BUMEL conditioning with respect to clinical course and treatment outcomes.

Results

The 3-year progression-free survival (PFS) was 52.5% for the HDMEL conditioning group versus 70.3% for the BUMEL conditioning group (P=0.043). The 3-year overall survival (OS) was 82.0% versus 83.5% (P=0.525), respectively. Although not statistically significant, BUMEL conditioning was associated with more platelet transfusion, while HDMEL was associated with more granulocyte colony stimulating factor support. In multivariate analysis, BUMEL conditioning was not inferior to HDMEL conditioning in regard to both PFS and OS.

Conclusion

Our study confirmed that BUMEL is an effective and well-tolerated alternative to HDMEL conditioning, with better PFS.

Pharmacokinetics-directed Intravenous Busulfan Combined With High-dose Melphalan and Bortezomib as a Conditioning Regimen for Patients With Multiple Myeloma

BACKGROUND

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) has a well-established role in the treatment of patients with multiple myeloma. Melphalan 200 mg/m² (Mel200) is the most commonly used preparative regimen. Several studies have provided evidence for potential synergism and safety when combining bortezomib (Btz) or busulfan (Bu) with melphalan (Mel).

PATIENTS AND METHODS

We conducted a prospective phase II study to investigate the safety and efficacy of conditioning with pharmacokinetics (PK)-directed intravenous (IV) Bu with Btz and Mel. Bu dosing was adjusted to target a total area under the curve (AUC) of 20,000 μM × min. Patients received Btz (1 mg/m² × 4 doses) and Mel (140 mg/m²).

RESULTS

A total of 19 subjects were enrolled. Their median age was 55 years, and the median follow-up period was 23.7 months. PK testing resulted in 86% of patients achieving an estimated total AUC of 20,000 ± 2500 μM × min. The overall response rate (ORR) at day +100 after ASCT was 100% in the evaluable patients, with 11% of patients achieving a complete response. The 2-year progression-free survival rate was 57.9% (95% confidence interval [CI], 38%-89%), and the 2-year overall survival rate was 88.5% (95% CI, 76%-100%). The most common grade 3 and 4 toxicities were febrile neutropenia, dysphagia/odynophagia, and oral mucositis. No case of hepatic sinusoidal obstruction syndrome developed. One treatment-related mortality occurred before day +100.

CONCLUSION

A preparative regimen of PK-directed IV Bu with Btz and Mel led to an ORR of 100% with acceptable toxicity and should be considered for direct comparison with the Mel200 regimen in future trials.

Filgrastim, lenograstim and pegfilgrastim in the mobilization of peripheral blood progenitor cells in patients with lymphoproliferative malignancies

Patients with lymphoproliferative disorders, candidate to autologous stem cell transplantation (ASCT), require mobilization with chemotherapy and granulocyte colony -stimulating factor (G-CSF). This study looked for differences in hematopoietic peripheral stem cells (HPSCs) mobilization in response to the three available G-CSFs, namely lenograstim, filgrastim, and pegfilgrastim. Between 2000 and 2012, 146 patients (66 M and 80 F) who underwent ASCT for multiple myeloma, non-Hodgkin's lymphoma or Hodgkin's lymphoma were studied. All patients received induction therapy and then a mobilization regimen with cyclophosphamide plus lenograstim, or filgrastim, or pegfilgrastim. From days 12 to 14, HPSCs were collected by two to three daily leukaphereses. Our results show that high-dose cyclophosphamide plus lenograstim achieved adequate mobilization and the collection target more quickly and with fewer leukaphereses as compared to filgrastim and pegfilgrastim. No differences between the three regimens were observed regarding toxicity and days to WBC and platelet recovery. Thus, lenograstim may represent the ideal G-CSF for PBSC mobilization in patients with lymphoproliferative diseases. Further studies are needed to confirm these results and better understand the biological bases of these differences.

Efficacy and safety of busulfan-based conditioning regimens for multiple myeloma

Multiple myeloma is a malignancy of B cells characterized by accumulation of abnormal plasma cells in the bone marrow. In the past 20 years, the use of high-dose therapies and novel agents has resulted in significant and meaningful improvements in survival. Autologous stem cell transplantation (auto-SCT) following a high-dose melphalan-conditioning regimen represents the standard of care for younger patients as well as older patients with a good performance status. A number of strategies have been proposed to improve the outcome of auto-SCTs, including the incorporation of new agents such as thalidomide, lenalidomide, and bortezomib into the induction regimen administered before auto-SCT; the administration of maintenance therapy after auto-SCT; the incorporation of novel agents into chemotherapeutic regimens after transplantation as consolidation therapy; and the use of reduced-intensity allogeneic transplantation after an initial autograft. Although these approaches have demonstrated some success in improving responses after auto-SCT, none of these strategies are curative. An additional strategy to improve outcomes after auto-SCT is to enhance the immediate pretransplant conditioning regimens by either increasing the dose of melphalan or by incorporating novel agents, such as busulfan. This literature review focuses on the efficacy and safety of busulfan-based conditioning regimens for auto-SCT in patients with multiple myeloma.

Haematopoietic stem cell transplantation as first-line treatment in myeloma: a global perspective of current concepts and future possibilities

Stem cell transplantation forms an integral part of the treatment for multiple myeloma. This paper reviews the current role of transplantation and the progress that has been made in order to optimize the success of this therapy. Effective induction chemotherapy is important and a combination regimen incorporating the novel agent bortezomib is now favorable. Adequate induction is a crucial adjunct to stem cell transplantation and in some cases may potentially postpone the need for transplant. Different conditioning agents prior to transplantation have been explored: high-dose melphalan is most commonly used and bortezomib is a promising additional agent. There is no well-defined superior transplantation protocol but single or tandem autologous stem cell transplantations are those most commonly used, with allogeneic transplantation only used in clinical trials. The appropriate timing of transplantation in the treatment plan is a matter of debate. Consolidation and maintenance chemotherapies, particularly thalidomide and bortezomib, aim to improve and prolong disease response to transplantation and delay recurrence. Prognostic factors for the outcome of stem cell transplant in myeloma have been highlighted. Despite good responses to chemotherapy and transplantation, the problem of disease recurrence persists. Thus, there is still much room for improvement. Treatments which harness the graft-versus-myeloma effect may offer a potential cure for this disease. Trials of novel agents are underway, including targeted therapies for specific antigens such as vaccines and monoclonal antibodies.

Busulfan 12 mg/kg plus melphalan 140 mg/m2 versus melphalan 200 mg/m2 as conditioning regimens for autologous transplantation in newly diagnosed multiple myeloma patients included in the PETHEMA/GEM2000 study

BACKGROUND

The aim of this study was to compare the long-term safety and efficacy of oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) and melphalan 200 mg/m(2) as conditioning regimens for autologous stem cell transplantation in newly diagnosed patients with multiple myeloma in the GEM2000 study.

DESIGN AND METHODS

The first 225 patients received oral busulfan 12 mg/kg plus melphalan 140 mg/m(2); because of a high frequency of veno-occlusive disease, the protocol was amended and a further 542 patients received melphalan 200 mg/m(2).

RESULTS

Engraftment and hospitalization times were similar in both groups. Oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) resulted in higher transplant-related mortality (8.4% versus 3.5%; P=0.002) due to the increased frequency of veno-occlusive disease in this group. Response rates were similar in both arms. With respective median follow-ups of 72 and 47 months, the median progression-free survival was significantly longer with busulfan plus melphalan (41 versus 31 months; P=0.009), although survival was similar to that in the melphalan 200 mg/m(2) group. However, access to novel agents as salvage therapy after relapse/progression was significantly lower for patients receiving busulfan plus melphalan (43%) than for those receiving melphalan 200 mg/m(2) (58%; P=0.01).

CONCLUSIONS

Conditioning with oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) was associated with longer progression-free survival but equivalent survival to that achieved with melphalan 200 mg/m(2) but this should be counterbalanced against the higher frequency of veno-occlusive disease-related deaths. This latter fact together with the limited access to novel salvage therapies in patients conditioned with oral busulfan 12 mg/kg plus melphalan 140 mg/m(2) may explain the absence of a survival difference. Oral busulfan was used in the present study; use of the intravenous formulation may reduce toxicity and result in greater efficacy, and warrants further investigation in myeloma patients. (Clinicaltrials.gov identifier: NCT00560053).

Endothelial differentiation of hematopoietic stem and progenitor cells from patients with multiple myeloma

PURPOSE

Vasculogenesis is a physiologic process typical of fetal development in which new blood vessels develop from undifferentiated precursors (or angioblasts). In tumors, near angiogenesis, vasculogenesis contributes to the formation of the microvascular plexus that is important for diffusion. Here, we show that hematopoietic stem and progenitor cells (HSPC) of multiple myeloma (MM) patients are able to differentiate into cells with endothelial phenotype on exposure to angiogenic cytokines.

EXPERIMENTAL DESIGN

Circulating HSPCs were purified with an anti-CD133 antibody from patients with newly diagnosed MM before autologous transplantation and exposed to vascular endothelial growth factor (VEGF), fibroblast growth factor-2 and insulin-like growth factor in a 3-week culture.

RESULTS

HSPCs gradually lost CD133 expression and acquired VEGF receptor-2, factor VIII-related antigen, and vascular endothelial-cadherin expression. The expression pattern overlapped with paired MM endothelial cells (MMEC). During culture, cells adhered to fibronectin, spread, and acquired an endothelial cell shape. Differentiated HSPCs also became capillarogenic in the Matrigel assay with maximal activity at the third week of culture. Bone marrow biopsies revealed HSPCs inside the neovessel wall in patients with MM but not in those with monoclonal gammopathy of undetermined significance.

CONCLUSIONS

In patients with MM, but not in those with monoclonal gammopathy of undetermined significance, HSPCs contribute to the neovessel wall building together with MMECs. Therefore, besides angiogenesis, HSPC-linked vasculogenesis contributes to neovascularization in MM patients. Tentatively, we hypothesize that in HSPC cultures a multipotent cell population expressing low VEGF receptor-2 levels corresponds to the endothelial progenitor cell precursor and seems to be the MMEC precursor.

Veno-occlusive disease of the liver after high-dose cytoreductive therapy with busulfan and melphalan for autologous blood stem cell transplantation in multiple myeloma patients

Veno-occlusive disease of the liver (VOD) is a potentially severe complication of high-dose cytoreductive therapy (HDT) used for stem cell transplantation (SCT). This complication is uncommon after HDT for autologous SCT (ASCT) in patients with multiple myeloma (MM). The Spanish Myeloma Group/PETHEMA conducted a study (MM2000) for patients with newly diagnosed MM consisting of induction with alternating VBMCP/VBAD chemotherapy followed by intensification with busulfan/melphalan (Bu/MEL) with a second high-dose therapy procedure in patients not achieving at least near-complete remission with the first procedure. After 2 years of the trial, a number of episodes resembling classical VOD but with a late onset were recognized. Consequently, the protocol was modified, and Bu/MEL was replaced by melphalan 200 mg/m(2) (MEL-200). Three years later, after a total of 734 patients had undergone first autologous SCT, the incidence and characteristics of VOD episodes were analyzed in the whole series. Nineteen cases of VOD (8%) were observed among the first 240 patients receiving Bu/MEL, whereas only 2 (0.4%) were observed among the 494 patients treated with MEL-200 (P < .0001). VOD manifestations in the Bu/MEL group appeared at a median of 29 days (range, 3-57 days) after ASCT. Mortality directly attributable to VOD was 2% in the Bu/MEL group and 0.2% in the MEL-200 group (P = .026). This high incidence of severe VOD probably had a multifactorial origin (busulfan followed by melphalan and previous use of BCNU). This observation should be kept in mind when designing future trials for the treatment of MM.

High-dose melphalan versus busulfan, cyclophosphamide, and etoposide as preparative regimens for autologous stem cell transplantation in patients with multiple myeloma

High-dose chemotherapy (HDC) with autologous stem cell transplant (ASCT) has improved response rates and survival for patients with multiple myeloma (MM). We report a single-institution experience using two conditioning regimens, busulfan, cyclophosphamide, and etoposide (BCV) or high-dose melphalan (HDM). Between July 1992 and August 2003, 110 patients with MM (median age=56.1) underwent HDC with ASCT using either BCV (n=62) or HDM (n=48) in sequential cohorts as the preparative regimen. Overall response rates, progression-free survival, and median overall survival were similar. BCV and HDM confer similar long-term outcomes with similar toxicity profiles as conditioning regimens prior to autologous stem cell transplant in patients with MM.

High-dose chemotherapy with autologous hematopoietic stem cell transplantation in patients with multiple myeloma

Multiple myeloma, for all practical purposes, remains an incurable malignancy; however, 5-year survival has improved substantially during the past 30 years. A major contribution to improved outcome is the use of high-dose chemotherapy and stem cell transplantation. This multifaceted approach to therapy requires an understanding of appropriate induction therapy, techniques for stem cell mobilization, appropriate conditioning and supportive care. Also of importance are prognosis, features that predict outcome, the suitability of transplant candidates, and post-transplantation maintenance therapy.

High-dose idarubicin, cyclophosphamide and melphalan as conditioning for autologous stem cell transplantation increases treatment-related mortality in patients with multiple myeloma: results of a randomised study

We conducted a randomised trial comparing an intensified versus a standard conditioning regimen for high-dose chemotherapy followed by autologous stem-cell transplantation in patients with multiple myeloma. In this study, 56 patients were randomly assigned for high-dose therapy with melphalan 200 mg/m2 or with idarubicin 42 mg/m2, melphalan 200 mg/m2 and cyclophosphamide 120 mg/kg. The primary objective was response rate. Acute toxicity, mainly because of infections, was higher in the intensified treatment arm with a treatment-related mortality of 20% versus 0% in the standard arm. This lead to the early discontinuation of the study. Response rates did not differ significantly between both treatment arms {intensified versus standard: complete response+near complete remission 50% [95% confidence interval (CI) 26-74%] vs. 33% (95% CI 17-55%), partial remission 35% (95% CI 16-61%) vs. 50% (95% CI 30-70%)}. After a follow-up of 5 years, the median time-to-progression and overall survival were not significantly different between both patient groups. Analysis restricted to patients surviving the first 100 d after transplant showed a better outcome for patients with >or=2 bad prognostic risk factors in the intensified treatment arm, however all treatment-related deaths occurred within this group of patients. In conclusion, intensified conditioning for high-dose therapy had intolerably high toxicity without improving outcome in patients with multiple myeloma.