Autologous haemopoietic stem-cell transplantation followed by allogeneic or autologous haemopoietic stem-cell transplantation in patients with multiple myeloma (BMT CTN 0102): a phase 3 biological assignment trial

A Pilot Study of UM171-Expanded Cord Blood Grafts for Tandem Auto/Allogeneic Hematopoietic Cell Transplant in High and Ultra-High-Risk Myeloma Patients

Multiple myeloma (MM) remains associated with a poor outcome, particularly in patients with advanced disease and high-risk (HR) cytogenetics. To date, the only curative treatment is allogeneic (allo) hematopoietic cell transplantation (HCT), but high incidences of graft versus host disease (GVHD), nonrelapse mortality (NRM) and disease progression remain important obstacles. Cord blood (CB) transplantation has been associated with low rates of relapse and chronic (c) GVHD, but its use has declined because of high incidences of infections, severe acute GVHD and high NRM. In other hematologic malignancies, UM171-expanded CB transplants have led to improved outcomes, allowing for the selection of smaller, better HLA-matched units. We aimed to investigate the safety and feasibility of single UM171-expanded single CB unit transplantation in frontline tandem auto/allo HCT for HR/ultra-HR MM patients. Newly diagnosed MM patients ≤ 65 years with an ISS stage II/III and del(17p), t(4;14), t(14;16), t(14;20), del(1p) or +1q, R-ISS 3, ≥ 2 cytogenetic abnormalities, or plasma cell leukemia without a sibling donor and availability of a 5-7/8 matched CB graft with ≥ 0.5 x 105 CD34+/kg and ≥ 1.5 x 107 TNCs/kg were eligible to this phase I/II prospective study (ClinicalTrials.gov NCT03441958). After induction and autologous HCT, patients received a reduced intensity conditioning regimen and were infused with 7-day UM171-expanded CD34+ cells, along with the lymphocytes contained in the CD34-negative fraction. The primary endpoints were feasibility of UM171 expansion, safety, kinetics of engraftment, incidences and maximum grades of acute and cGVHD at 1 and 2 years, assessment of measurable residual disease (MRD) and quality of life (QoL). Between 05/2018 and 11/2021, 20 patients were enrolled. One patient had an unsuccessful CB expansion with UM171, leaving 19 patients with a median age of 56 years. Median CD34+ cell dose infused after expansion was 4.62 x 106/kg (range: 0.79 to 5.76). Median times to achieve absolute neutrophil counts of 0.1 and 0.5 x 109/L were D+6 and D+10.5; median time to reach ≥ 20 x 109/L platelets was D+36. Full donor chimerism was achieved in all cell lineages by D+120 in recipients of reduced intensity conditioning. Cumulative incidences of grade II-IV, grade III-IV acute GVHD and moderate/severe cGVHD at 12 months were 68.4% (95% CI: 46 to 90), 5.3% (95% CI: 0% to 16%), and 10.5% (95% CI: 0% to 25%), respectively. With a median follow-up of 2.9 years (range: 0.46 to 5.3), cumulative incidences of relapse, PFS, OS and NRM at 3 years were 36.8% (95% CI: 14 to 59), 47.4% (95% CI: 29 to 76), 68.4% (95% CI: 50 to 93) and 15.8% (95%CI: 0 to 33), respectively. Median time to complete immunosuppression discontinuation was D+238. No unexpected adverse events were observed. Only one of 7 patients alive at 2 years with negative MRD at transplant has relapsed. Non-relapsing patients had a QoL after transplant similar to the general population. UM171-expanded CB transplant in HR/ultra-HR myeloma patients is feasible and allows the use of single CB units with a low risk of cGVHD. Patients with negative pretransplant MRD might benefit most from a UM171-expanded CB transplant.

Historical Perspective of Allogeneic Hematopoietic Stem Cell Transplantation for Multiple Myeloma

BACKGROUND

Advances in novel therapies have improved outcomes for multiple myeloma (MM) patients and the use of allo-SCT has decreased. Current guidelines no longer support allo-SCT as consolidation therapy for newly diagnosed MM, even in high-risk cases.

SUMMARY

Allo-SCT is now typically considered only within clinical trials for young, high-risk patients with relapsed or refractory MM (RRMM). It has not proven favorable despite its historical use. CAR T-cell therapy and bispecific antibodies have shown promise in treating triple- and penta-exposed/refractory MM, yet relapse remains common with poor survival rates. The efficacy of allo-SCT following BCMA-directed therapy and other new T-cell-directed therapies is unclear. Allo-SCT might be a viable option for eligible patients who relapse after these therapies, or where such options are unavailable. Advancements in reduced-intensity conditioning regimens have led to lower toxicity and transplant-related (TR) morbidity, lower graft-versus-host disease (GvHD), and TR mortality. Expanded use of alternative donors, like haploidentical donors, has yielded comparable outcomes. Better post-transplant GvHD regimens and maintenance strategies to prevent relapse have been developed.

KEY MESSAGES

This review analyzes available literature to better understand the safety, efficacy, and current role of allo-SCT in managing MM. Newer regimens are needed as routine use of allo-SCT cannot be recommended.

Allogeneic stem cell transplantation in multiple myeloma: is there still a place?

The introduction of novel agents dramatically improved response and outcomes of multiple myeloma (MM) and led to a sharp decline in the use of allogeneic hematopoietic stem-cell transplantation (allo-HSCT). Thus, recent guidelines do not recommend anymore allo-HSCT as consolidation in the first-line treatment of newly diagnosed MM, even in high-risk patients. In a relapsed/refractory setting, allo-HSCT is not routinely recommended but should only be performed within clinical trials in young and high-risk patients. Nonetheless, allo-HSCT still represents a potential curative approach that has been used for decades in the treatment of MM and plasma cell neoplasms with favorable results and may still represent a treatment option for carefully selected patients. Despite that promising results were obtained with CAR T-cell therapies and bispecific antibodies in triple- and penta-exposed/refractory MM, these patients will inevitably relapse. To date, less is known about outcomes of allo-HSCT in patients exposed to novel immunotherapeutic drugs. Therefore, allo-HSCT could represent a reasonable treatment choice for younger and high-risk patients who have relapsed after CAR T-cell therapies and bispecific antibodies as well as an alternative for patients not eligible to these treatments and in those countries where immunotherapies are not yet available. In the choice of conditioning, reduced intensity conditioning regimens are currently recommended for the lower toxicity and mortality. Moreover, the use of alternative donors, particularly haploidentical, has progressively increased in last years with results comparable to full matched donors. Finally, post-transplantation maintenance strategies are encouraged whenever feasible.

Autologous-allogeneic versus autologous tandem stem cell transplantation and maintenance therapy with thalidomide for multiple myeloma patients under 60 years of age: a prospective, phase II study

The role of autologous-allogeneic tandem stem cell transplantation (alloTSCT) followed by maintenance as upfront treatment for multiple myeloma is controversial. Between 2008 and 2014 a total of 217 multiple myeloma patients with a median age of 51 years were included by 20 German centers within an open-label, parallel-group, multicenter clinical trial to compare alloTSCT to autologous tandem transplantation (autoTSCT) followed by 2 years of maintenance therapy with thalidomide (100 mg/day) in both arms with respect to relapse/progression-free survival (PFS) and other relevant outcomes. A total of 178 patients underwent a second transplant (132 allogeneic, 46 autologous). PFS at 4 years after the second transplant was 47% (95% CI: 38-55%) for alloTSCT and 35% (95% CI: 21-49%) for autoTSCT (P=0.26). This difference increased to 22% at 8 years (P=0.10). The cumulative incidences of non-relapse mortality and of relapse at 4 years were 13% (95% CI: 8-20%) and 2% (95% CI: 0.3-2%) (P=0.044) and 40% (95% CI: 33-50%) and 63% (95% CI: 50-79%) (P=0.04) for alloTSCT and autoTSCT, respectively. The difference for relapse/progression increased to 33% (alloTSCT: 44%, autoTSCT: 77%) at a median follow-up of 82 months (P=0.002). Four-year overall survival was 66% (95% CI: 57-73%) for alloTSCT and 66% (95% CI: 50-78%) for autoTSCT (P=0.91) and 8-year overall survival was 52% and 50% (P=0.87), respectively. In conclusion, alloTSCT followed by thalidomide maintenance reduced the rate of recurrence or progression during a follow-up period of up to 10 years but failed to improve PFS significantly. This study was registered with ClinicalTrials.gov (NCT00777998).

[Clinical analysis of 14 patients aged ≤ 50 years with high-risk multiple myeloma treated with allogeneic hematopoietic stem cell transplantation]

Objective: To evaluate the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in young patients with high-risk multiple myeloma (HRMM) and analyzed the factors affecting patient prognosis. Methods: In this retrospective study, we analyzed the clinical data of 14 patients with HRMM with cytogenetic abnormalities or high-risk biological factors who underwent allo-HSCT at the Hematopoietic Stem Cell Transplantation Center of the Institute of Hematology & Blood Diseases Hospital between November 2016 and November 2022. Results: There were seven males and seven females included in the study, with a median age of 39.5 (31-50) years at the time of allo-HSCT. The median number of treatment lines before transplantation was 2 (1-6) . Before allo-HSCT, 42.9% (6/14) of the patients did not achieve complete remission, while 35.7% (5/14) of the patients achieved measurable residual disease positivity. After transplantation, all patients were evaluated for their treatment response, and the overall response rate was 100% (14/14) . All 14 patients successfully underwent allo-HSCT, with median engraftment times for neutrophils and platelets of 11 (10-14) days and 13 (9-103) days, respectively. Acute grade Ⅱ-Ⅳ graft-versus-host disease (GVHD) occurred in five patients (35.7%) , and two patients (14.3%) developed moderate-to-severe chronic GVHD. The median follow-up time after allo-HSCT was 18.93 (4.10-72.53) months, with an expected 2-year transplant-related mortality rate of 7.1% (95% CI 0%-21.1%) and an expected 2-year overall survival rate of 92.9% (95% CI 80.3%-100.0%) . Moreover, the expected 1-year and 2-year progression-free survival rates were 92.9% (95% CI 80.3%-100.0%) and 66.0% (95% CI 39.4%-100.0%) , respectively, and the 2-year cumulative incidence of relapse was 28.9% (95% CI 0%-56.7%) . Upfront allo-HSCT following complete remission after induced therapy and the presence of chronic GVHD might be favorable prognostic factors. Conclusion: allo-HSCT is an effective treatment for improving the prognosis of young patients with HRMM.

Autologous followed by allogeneic versus tandem-autologous transplantation in high-risk, newly diagnosed multiple myeloma: a systematic review and meta-analysis

OBJECTIVES

High-risk multiple myeloma (HRMM) is associated with poor survival, despite many advances in antimyeloma strategies. Autologous followed by allogeneic stem cell transplantation (auto-allo-SCT) has yielded controversial results compared to tandem autologous stem cell transplantation (auto-SCT) in patients with HRMM. We conducted this meta-analysis to compare the efficacy and safety of auto-allo-SCT and tandem-auto-SCT in patients with HRMM.

METHODS

Embase, Cochrane Library, and PubMed databases were searched until March 2023. Prospective or retrospective studies comparing the effects of auto-allo-SCT and tandem-auto-SCT were included. Hazard ratios (HRs) and 95% confidence intervals (CIs) for time-to-event outcomes, and odds ratios (ORs) and 95%CIs for dichotomous outcomes were pooled using random-effects models.

RESULTS

Three studies involving 491 patients were included. Despite auto-allo-SCT seemed to be associated with improvements in progression-free survival (PFS) (HR [95%CI], 0.71 [0.51-1.00]) and complete response (CR) (OR [95%CI], 3.16 [1.67-5.99]), and reduced relapse/progression rates (47% vs. 55%) in comparison with tandem-auto-SCT, no marked improvement in overall survival (OS). In comparison to tandem-auto-SCT, patients assigned to auto-allo-SCT exhibited a higher risk of transplant-related mortality (TRM) (11.9% vs. 4.1%) and non-relapse mortality (NRM) (12.3% vs. 3.1%).

CONCLUSION

Auto-allo-SCT seemed to be associated with improvements in PFS and CR when compared to tandem-auto-SCT in patients with HRMM, but it did not lead to a significant improvement in OS. Furthermore, patients in the auto-allo-SCT group were at a higher risk of developing TRM and NRM. Auto-allo-SCT transplantation should not be routinely incorporated into HRMM therapy but rather should be considered investigational.

Long-term outcomes of allogeneic stem cell transplant in multiple myeloma

Allogeneic stem cell transplant (allo SCT) for multiple myeloma (MM) is potentially curative in some, while toxic in many others. We retrospectively analyzed 85 patients diagnosed with MM who underwent allo SCT as frontline or salvage therapy between 2000 and 2022 at Mayo Clinic Rochester and examined patient outcomes and prognostic markers. Overall survival (OS), progression free survival (PFS), treatment related mortality (TRM), and relapse rates (RR) were estimated using the Kaplan Meier method and competing risk models. Median follow-up was 11.5 years. Median OS and PFS were 1.7 and 0.71 years, respectively. Five-year OS and PFS were 22.2% and 15.1%, respectively. One-year TRM was 23.5%. Twelve patients demonstrated durable overall survival, living 10+ years beyond their allo SCT. This subgroup was more likely to have no or one prior auto SCT (p = 0.03) and to have been transplanted between 2000 and 2010 (p = 0.03). Outcomes were poor in this cohort with long follow-up, with few patients surviving 5 years or more, and most relapsing or dying within 2 years. We would expect better outcomes and tolerability with an expanded array of novel therapeutics and would prefer them to allo SCT.

Prophylactic or pre-emptive therapies to prevent relapse after allogeneic hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation is a potent curative treatment for hematological malignancies, but relapse is still a major problem. Donor lymphocyte infusion (DLI) and maintenance therapies after transplantation are promising strategies to reduce the risk of relapse. DLI augments the graft-versus-tumor effect by directly adding allo-reactive donor lymphocytes, and has been used in relapsed patients. In this Progress in Hematology (PIH), we will focus on prophylactic or pre-emptive DLI, including DLI from a haploidentical donor. On the other hand, specific drugs, which are used in maintenance therapies for each disease, kill tumor cells directly and/or immunologically by stimulating immune cells. Maintenance therapies should be started early after transplantation without severe myelosuppression. Molecularly targeted drugs are therefore suitable for use in maintenance therapies, and are reviewed in this PIH. The optimal application of these strategies has not yet been established. However, important evidence regarding their efficacies, adverse events, and effects on immune systems is accumulating, and could help to improve outcomes in allogeneic transplantation.

A Multicenter Phase II, Double-Blind, Placebo-Controlled Trial of Maintenance Ixazomib After Allogeneic Transplantation for High-Risk Multiple Myeloma: Results of the Blood and Marrow Transplant Clinical Trials Network 1302 Trial

The role of allogeneic hematopoietic cell transplantation (allo-HCT) followed by maintenance therapy in high-risk multiple myeloma (MM) remains controversial. We evaluated the efficacy of ixazomib maintenance therapy after reduced-intensity conditioning allo-HCT from HLA-matched donors in patients with high-risk MM. The primary study endpoint was progression-free survival (PFS) postrandomization, treated as a time to event. Secondary endpoints were grade II-IV and grade II-IV acute graft-versus-host-disease (GVHD), chronic GVHD, best response, disease progression, nonrelapse mortality (NRM), overall survival (OS), toxicity, infection, and health-related quality of life. In this phase 2, double-blinded, prospective multicenter trial, we randomized patients with high-risk MM (ie, those with poor-risk cytogenetics, plasma cell leukemia, or relapsing within 24 months after autologous HCT) to ixazomib (3 mg on days 1, 8, and 15) or placebo after allo-HCT. The conditioning regimen included fludarabine/melphalan/bortezomib with tacrolimus plus methotrexate for GVHD. Fifty-seven patients were enrolled, of whom 52 (91.2%) underwent allo-HCT and 43 (82.7%) were randomized to ixazomib versus placebo. At 21 months postrandomization, the ixazomib and placebo groups had similar PFS (55.3% versus 59.1%; P = 1.00) and OS (94.7% versus 86.4%; P = .17). The cumulative incidences of grade III-IV acute GVHD at 100 days (9.5% versus 0%) and chronic GVHD at 12 months (68.6% versus 63.6%) also were similar in the 2 groups. The secondary analysis showed that at 24 months post-allo-HCT, PFS and OS were 52% and 82%, respectively, with a corresponding NRM of 11.7%. These results demonstrate the safety and durable disease control with allo-HCT in high-risk MM patients. We could not adequately assess the efficacy of ixazomib maintenance because the trial terminated early owing to enrollment delays, but there was no indication of any impact on outcomes.

Biological research on the occurrence and development of multiple myeloma and its treatment

INTRODUCTION

To review the pathogenesis and treatment of multiple myeloma (MM). MM is a hematological malignancy with abnormal plasma cell proliferation in bone marrow. Due to the emergence of drug resistance, MM is still an incurable malignancy, which requires further exploration of pathogenesis and effective therapeutic targets.

METHODS

In this paper, the method of literature review is adopted to obtain the information about MM. Based on the literature, comprehensive and systematic review is made.

RESULTS

MM is a complex pathophysiological process with great heterogeneity, mainly reflected in genomic instability and bone marrow microenvironment. At present, the treatment of MM has made great progress, proteasome inhibitors and immunomodulatory drugs are widely used in clinic. Allogeneic stem cell transplantation may be the only promising cure for MM, and its high transplant-related mortality limits its clinical application.

CONCLUSIONS

The future of MM treatment lies in the development of more targeted therapies, novel immunotherapies, and a better understanding of the disease's molecular and genetic basis.

Maintenance therapy after allogeneic hematopoietic stem cell transplantation for patients with multiple myeloma

In the last two decades, proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), and monoclonal antibodies have greatly improved the overall survival of patients with multiple myeloma. However, multiple myeloma remains incurable, and high-risk patients have poor long-term survival. Although allogeneic hematopoietic stem cell transplantation (allo-HCT) is not considered standard therapy because of relatively high transplant-related mortality and relapse rates, the graft-versus-myeloma (GVM) effect makes it a potentially curative therapy. Therefore, allo-HCT remains a treatment option for younger patients and those with high-risk myeloma. Maintenance therapy with novel agents has recently been attempted to reduce relapse in patients undergoing allo-HCT, but its effectiveness remains unclear. This review focuses on the role of maintenance therapy after allo-HCT in patients with myeloma. Maintenance therapy using IMiDs and/or PIs after allo-HCT may be effective in reducing relapse or improving response because it may prevent early progression before achievement of the GVM effect or enhance the GVM effect. However, care must be taken to avoid complications, such as graft-versus-host disease. Further studies are necessary to determine the optimal maintenance drugs, drug combinations, dosing, start timing, and number of cycles.

Long-Term Outcomes of Allogeneic Hematopoietic Cell Transplantation in Patients with Newly Diagnosed Multiple Myeloma

Despite remarkable progress in survival with the availability of novel agents, an overwhelming majority of patients with multiple myeloma (MM) have disease that relapses. Allogeneic (allo-) hematopoietic cell transplantation (HCT) is a potentially curative option for a subgroup of patients with high-risk MM. This study assessed the long-term outcome of MM patients who underwent allo-HCT while in first remission as consolidation treatment. Thirty-three patients with newly diagnosed MM who underwent allo-HCT as part of consolidation therapy between 1994 and 2016 were reviewed retrospectively. Of these patients, 70% underwent autologous HCT before allo-HCT. All patients were chemosensitive and achieved at least partial response before proceeding to allo-HCT. Most received nonmyeloablative/reduced-intensity conditioning (88%) and a matched sibling donor graft (85%). Acute graft-versus-host disease (GVHD) and chronic GVHD occurred in 30% and 61% of patients, respectively. The median duration of follow-up was 64.1 months (range, 1.4 to 199.2 months) for all patients and 164.4 months (range, 56.0 to 199.2 months) for survivors. The median progression-free survival (PFS) was 36 months (95% confidence interval (CI), 8.6 to 73.0 months). The median time from treatment to progression was 73.0 months (95% CI, 30.6 months to not reached). The median overall survival (OS) was 131.9 months (95% CI, 38.4 months to not reached). Of all patients, 39% were alive for more than 10 years, with 46% (n = 6) without progression or relapse. The cumulative incidence of relapse was 18% at 1 year, 39% at 5 years, and 46% at 10 years post-allo-HCT. The cumulative incidence of nonrelapse mortality was 3% at 100 days, 18% at 1 year, 21% at 3 years, and 24% at 5 year post-allo-HCT. On multivariable analysis, high-risk cytogenetics were associated with a shorter PFS (hazard ratio [HR], 2.7; 95% CI, 1.01 to 7.21; P = .047) and OS (HR, 4.91; 95% CI, 1.48 to 16.27; P = .009). Achieving complete remission after allo-HCT also was associated with longer PFS (HR, 0.24; 95% CI, 0.09 to 0.64; P = .004) and OS (HR, .23; 95% CI, .07 to .72; P = .012). Allo-HCT may confer a survival advantage in a selected population of MM patients when performed early in the disease course; additional data on identifying the patients who will benefit the most are needed.

Quadruple gene-engineered natural killer cells enable multi-antigen targeting for durable antitumor activity against multiple myeloma

Allogeneic natural killer (NK) cell adoptive transfer is a promising treatment for several cancers but is less effective for the treatment of multiple myeloma. In this study, we report on quadruple gene-engineered induced pluripotent stem cell (iPSC)-derived NK cells designed for mass production from a renewable source and for dual targeting against multiple myeloma through the introduction of an NK cell-optimized chimeric antigen receptor (CAR) specific for B cell maturation antigen (BCMA) and a high affinity, non-cleavable CD16 to augment antibody-dependent cellular cytotoxicity when combined with therapeutic anti-CD38 antibodies. Additionally, these cells express a membrane-bound interleukin-15 fusion molecule to enhance function and persistence along with knock out of CD38 to prevent antibody-mediated fratricide and enhance NK cell metabolic fitness. In various preclinical models, including xenogeneic adoptive transfer models, quadruple gene-engineered NK cells consistently demonstrate durable antitumor activity independent of exogenous cytokine support. Results presented here support clinical translation of this off-the-shelf strategy for effective treatment of multiple myeloma.

Chimeric Antigen Receptor T Cell Therapy versus Hematopoietic Stem Cell Transplantation: An Evolving Perspective

Cellular therapy modalities, including autologous (auto-) hematopoietic cell transplantation (HCT), allogeneic (allo-) HCT, and now chimeric antigen receptor (CAR) T cell therapy, have demonstrated long-term remission in advanced hematologic malignancies. Auto-HCT and allo-HCT, through hematopoietic rescue, have permitted the use of higher doses of chemotherapy. Allo-HCT also introduced a nonspecific immune-mediated targeting of malignancy resulting in protection from relapse, although at the expense of similar targeting of normal host cells. In contrast, CAR T therapy, through genetically engineered immunotherapeutic precision, allows for redirection of autologous immune effector cells against malignancy in an antigen-specific and MHC-independent fashion, with demonstrated efficacy in patients who are refractory to cytotoxic chemotherapy. It too has unique toxicities and challenges, however. Non-Hodgkin lymphoma (including large B cell lymphoma, mantle cell lymphoma, and follicular lymphoma), B cell acute lymphoblastic leukemia, and multiple myeloma are the 3 main diseases associated with the use of fully developed CAR T products with widespread deployment. Recent and ongoing clinical trials have been examining the interface among the 3 cellular therapy modalities (auto-HCT, allo-HCT, and CAR T) to determine whether they should be "complementary" or "competitive" therapies. In this review, we examine the current state of this interface with respect to the most recent data and delve into the controversies and conclusions that may inform clinical decision making.

Prolonged hematological toxicity in patients receiving BCMA/CD19 CAR-T-cell therapy for relapsed or refractory multiple myeloma

Although chimeric antigen receptor T (CAR-T) cell therapy has been indicated to be effective in treating relapsed or refractory multiple myeloma (R/R MM), severe hematological toxicity (HT) remains an intractable issue. This study enrolled 54 patients with R/R MM following combined infusion of anti-CD19 and anti-BCMA CAR-T cells. The results showed that the rates of severe cytopenia were high, including severe neutropenia (28/54, 52%), severe anemia (15/54, 28%), and severe thrombocytopenia (18/54, 33%). Moreover, the incidence of prolonged HT (PHT) on Day 28 post-infusion was 52% (28/54), including 46% for severe neutropenia, 30% for severe anemia, and 31% for severe thrombocytopenia. Patients with PHT had a poorer median progression-free survival (PFS) and overall survival (OS) than patients without PHT (P=0.011; P=0.007). Furthermore, Cox regression analyses showed that PHT was an independent risk factor for PFS and OS. Univariate analyses showed that IFNγ (OR: 1.046; 95% CI: 1.002-1.093, P=0.042) and severe HT after lymphodepletion chemotherapy (OR: 0.082; 95% CI: 0.017-0.404; P=0.002) were independent risk factors for PHT. In conclusion, these results indicated that PHT was associated with poor outcomes following CAR-T-cell therapy in MM patients. Early detection and management of PHT would be beneficial for the prevention of life-threatening complications and improvement in the survival of patients after CAR-T-cell therapy.

Multiple myeloma: 2022 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

Multiple myeloma accounts for approximately 10% of hematologic malignancies.

DIAGNOSIS

The diagnosis requires ≥10% clonal bone marrow plasma cells or a biopsy-proven plasmacytoma plus evidence of one or more multiple myeloma defining events (MDE): CRAB (hypercalcemia, renal failure, anemia, or lytic bone lesions) attributable to the plasma cell disorder, bone marrow clonal plasmacytosis ≥60%, serum involved/uninvolved free light chain (FLC) ratio ≥ 100 (provided involved FLC is ≥100 mg/L), or >1 focal lesion on magnetic resonance imaging.

RISK STRATIFICATION

The presence of del(17p), t(4;14), t(14;16), t(14;20), gain 1q, or p53 mutation is considered high-risk multiple myeloma. The presence of any two high risk factors is considered double-hit myeloma, and three or more high risk factors is triple-hit myeloma.

RISK-ADAPTED INITIAL THERAPY

In patients who are candidates for autologous stem cell transplantation, induction therapy consists of bortezomib, lenalidomide, dexamethasone (VRd) given for approximately 3-4 cycles followed by autologous stem cell transplantation (ASCT). In high-risk patients, daratumumab, bortezomib, lenalidomide, dexamethasone (Dara-VRd) is an alternative to VRd. Selected standard-risk patients can collect stem cells, get additional cycles of induction therapy, and delay transplant until first relapse. Patients who are not candidates for transplant are treated with VRd for approximately 8-12 cycles followed by maintenance or alternatively with daratumumab, lenalidomide, dexamethasone (DRd) until progression.

MAINTENANCE THERAPY

Standard-risk patients need lenalidomide maintenance, while bortezomib plus lenalidomide maintenance is needed for high-risk myeloma.

MANAGEMENT OF RELAPSED DISEASE

A triplet regimen is usually needed at relapse, with the choice of regimen varying with each successive relapse.

Upfront tandem autologous non-myeloablative allogeneic stem cell transplant in high-risk multiple myeloma: a long-term single-centre experience

The role of upfront non‐myeloablative allogeneic stem cell transplantation (NMA alloSCT) in high‐risk multiple myeloma (HR‐MM) is unclear. We evaluated outcomes of NMA alloSCT following autologous stem cell transplant (ASCT) compared with ASCT alone for newly diagnosed HR‐MM. Two‐year progression‐free survival was improved in the ASCT‐NMA alloSCT group (44% vs 16%; P = 0.035), with a trend for improved overall survival (P = 0.118). These results suggest that ASCT‐NMA alloSCT can be considered as upfront therapy in HR‐MM.

Long-Term Follow-Up of Multiple Myeloma Patients Treated with Tandem Autologous Transplantation Following Melphalan and Upon Recovery, Total Marrow Irradiation

BACKGROUND

Total body irradiation in combination with melphalan for multiple myeloma (MM), was shown to be prohibitively toxic. To ameliorate toxicity, total marrow irradiation (TMI), was given as the sole ablative modality during the second cycle of tandem autologous stem cell transplant (TASCT) for MM patients on a phase I-II trial.

STUDY DESIGN

Patients with MM in response or with stable disease and ≤ 18 months from diagnosis received melphalan (MEL) 200 mg/m² and ASCT (Cycle 1), and, after recovery, TMI and ASCT (Cycle 2) followed by maintenance with an IMiD and dexamethasone for up to 12 months. TMI doses were escalated from 1,000 cGy to 1,800 cGy by 200 cGy increments.

RESULTS

Fifty-four patients were to receive TASCT between 2004 and 2011; 8 patients received single ASCT due to patient or physician preference. The median time between melphalan and TMI was 65 days (range 47-125). Thirty patients (55•6%) received TASCT at the maximum tolerated dose of 1600 cGy. The complete and very good partial response rates were 48•1% and 22•2% following ASCT and maintenance. Median follow-up among survivors was 12.3 years (range: 9•2-15•5+). Progression free survival and overall survival at 10 years was 20•4% (95% CI 10•9-31•9) and 38•8% (95% CI: 25•9-51•5). Secondary neoplasms included (1 each) acute myeloid leukemia, papillary thyroid and prostate carcinoma, and melanoma, and we observed 1 case of ductal carcinoma in situ and 4 patients with non-melanoma skin cancers.

CONCLUSION

TMI as part of TASCT was well-tolerated and TASCT lead to a 20.4% PFS plateau. The inclusion of TMI as a conditioning regiment for MM prior to ASCT warrants further study in the context of modern induction and maintenance therapies.

Current approaches to management of newly diagnosed multiple myeloma

Major developments in the treatment of multiple myeloma (MM) over the past decade have led to a continued improvement in survival. Significant progress has been made with deeper and longer remissions seen with newer treatment approaches-both for induction as well as maintenance therapy. The treatment approach to MM is guided by several factors including patient age, frailty, comorbidities, eligibility for autologous stem cell transplantation (ASCT), and risk stratification into standard-risk or high-risk MM. High-risk MM is defined by the presence of t(4;14), t(14;16), t(14;20), del (17p), TP53 mutation, or gain (1q). Transplant eligible patients should receive 4-6 cycles of induction followed by stem cell collection. Patients can then undergo ASCT, or continue induction therapy and shift to maintenance, delaying ASCT till first relapse. Transplant ineligible patients should receive induction therapy followed by maintenance. For induction therapy prior to ASCT, a proteasome inhibitor-IMiD combination remains standard with monoclonal antibody-based quadruplets preferred in high-risk patients. Among transplant ineligible patients, those with standard-risk MM should receive DRd continued until disease progression, while bortezomib containing regimens (VRd or VRd lite) can be considered for high-risk patients. Finally, standard-risk patients should receive lenalidomide maintenance after induction/ASCT, while proteasome inhibitor-IMiD combinations should be used for high-risk patients.

Current Role of Allogeneic Stem Cell Transplantation in Multiple Myeloma

Major progress in the treatment of multiple myeloma has been made in the last several years. However, myeloma remains incurable and patients with high-risk cytogenetics or advanced stage disease have an even worsen survival. Only allogeneic transplantation may have curative potential in some patients. However, the high non-relapse mortality and incidence of chronic graft-versus-host disease have raised controversy regarding this procedure. In this review, we will address the role of upfront and delayed allogeneic transplant.

Diagnosis and Management of Multiple Myeloma: A Review

IMPORTANCE

Multiple myeloma is a hematologic malignancy characterized by presence of abnormal clonal plasma cells in the bone marrow, with potential for uncontrolled growth causing destructive bone lesions, kidney injury, anemia, and hypercalcemia. Multiple myeloma is diagnosed in an estimated 34 920 people in the US and in approximately 588 161 people worldwide each year.

OBSERVATIONS

Among patients with multiple myeloma, approximately 73% have anemia, 79% have osteolytic bone disease, and 19% have acute kidney injury at the time of presentation. Evaluation of patients with possible multiple myeloma includes measurement of hemoglobin, serum creatinine, serum calcium, and serum free light chain levels; serum protein electrophoresis with immunofixation; 24-hour urine protein electrophoresis; and full-body skeletal imaging with computed tomography, positron emission tomography, or magnetic resonance imaging. The Revised International Staging System combines data from the serum biomarkers β2 microglobulin, albumin, and lactate dehydrogenase in conjunction with malignant plasma cell genomic features found on fluorescence in situ hybridization-t(4;14), del(17p), and t(14;16)-to assess estimated progression-free survival and overall survival. At diagnosis, 28% of patients are classified as having Revised International Staging stage I multiple myeloma, and these patients have a median 5-year survival of 82%. Among all patients with multiple myeloma, standard first-line (induction) therapy consists of a combination of an injectable proteasome inhibitor (ie, bortezomib), an oral immunomodulatory agent (ie, lenalidomide), and dexamethasone and is associated with median progression-free survival of 41 months, compared with historical reports of 8.5 months without therapy. This induction therapy combined with autologous hematopoietic stem cell transplantation followed by maintenance lenalidomide is standard of care for eligible patients.

CONCLUSIONS AND RELEVANCE

Approximately 34 920 people in the US and 155 688 people worldwide are diagnosed with multiple myeloma each year. Induction therapy with an injectable proteasome inhibitor, an oral immunomodulatory agent and dexamethasone followed by treatment with autologous hematopoietic stem cell transplantation, and maintenance therapy with lenalidomide are among the treatments considered standard care for eligible patients.

Allogeneic Stem Cell Transplantation in Multiple Myeloma

The development of new inhibitory and immunological agents and combination therapies significantly improved response rates and survival of patients diagnosed with multiple myeloma (MM) in the last decade, but the disease is still considered to be incurable by current standards and the prognosis is dismal especially in high-risk groups and in relapsed and/or refractory patients. Allogeneic hematopoietic stem cell transplantation (allo-SCT) may enable long-term survival and even cure for individual patients via an immune-mediated graft-versus-myeloma (GvM) effect, but remains controversial due to relevant transplant-related risks, particularly immunosuppression and graft-versus-host disease, and a substantial non-relapse mortality. The decreased risk of disease progression may outweigh this treatment-related toxicity for young, fit patients in high-risk constellations with otherwise often poor long-term prognosis. Here, allo-SCT should be considered within clinical trials in first-line as part of a tandem approach to separate myeloablation achieved by high-dose chemotherapy with autologous SCT, and following allo-SCT with a reduced-intensity conditioning to minimize treatment-related organ toxicities but allow GvM effect. Our review aims to better define the role of allo-SCT in myeloma treatment particularly in the context of new immunomodulatory approaches.

Outcomes in newly diagnosed young or high-risk myeloma patients receiving tandem autologous/allogeneic transplant followed by bortezomib maintenance: a phase II study

Despite novel drugs and autologous HCT, MM remains incurable, with short survival in patients with poor biological characteristics. Allo HCT may be curative in some patients but is hampered by high rates of toxicity and relapse. We hypothesized that bortezomib (BTZ), with its anti-myeloma and immunologic properties, could improve PFS and cGVHD after allo HCT in newly diagnosed MM patients. In this prospective phase II study, we included 39 young (≤50 years) and high-risk patients who received a tandem auto-allo HCT followed by BTZ. Patients had prospective minimal residual disease (MRD) evaluations using Next-Generation Flow cytometry prior to allo HCT, prior BTZ and every 3 months for 2 years. With a median follow-up of 48 months, we report PFS and OS at 5 years of 41% and 80%, with a non-relapse mortality of 12%. Incidences of grade II-IV aGVHD at 12 months and moderate/severe cGVHD at 2 years were 26% and 57%. In a multivariate analysis model including cytogenetics, ISS and MRD status, MRD positivity prior to allo HCT (HR 3.75, p = 0.037), prior BTZ (HR 11.3, p = 0.018) and 3 months post-BTZ initiation (HR 9.7, p = 0.001) was highly predictive of progression. Peritransplant MRD assessment thus strongly predicts disease progression.

Knowing the unknowns in high risk multiple myeloma

High risk multiple myeloma (HRMM) continues to portend worse outcomes despite the many advances in anti-myeloma therapeutics. The optimal approach to treatment is not clearly defined on account of the variable definitions of HRMM and the paucity of studies dedicated to the treatment of HRMM. In this review, we use a case-based approach to review the definitions of HRMM, and evaluate the evidence for induction, stem cell transplantation, and post-transplant therapy approaches for HRMM.

Allogeneic hematopoietic stem cell transplantation in patients with multiple myeloma

Aim. To analyze the effectiveness of allogeneic hematopoietic stem cell transplantation (allo-HSCT) from a related HLA-identical donor in patients with multiple myeloma (MM). Materials and methods. From 2013 to 2018, the study included 8 patients (6 men, 2 women) aged from 27 to 55 years (median 39 years) with MM who underwent allo-HSCT from a related HLA-identical donor (7 patients after auto-HSCT, in 1 case without previous auto-transplantation). All patients required 2 or more lines of induction therapy, while the achieved antitumor effect was unstable. Before allo-HSCT, complete and very good partial remission was determined in isolated cases, in 4 patients the response was regarded as partial remission, stabilization in 1 observation, progression in 1 patient. All patients underwent reduced intensity conditioning (fludarabine 30 mg/m2 6 days + busulfan 4 mg/kg 2 days). Immunosuppressive therapy included the administration of antithymocyte globulin and post-transplant cyclophosphamide. Results. Severe acute GVHD (grade 34) was observed in 3 (37.5%) cases, which resulted in death in 1 case. A stable antitumor response was achieved in 5 (62.5%) patients, complete remission lasts for 2986 months after allo-HSCT. Specific therapy for these patients is not carried out. The 7-year progression-free survival rate was 75%, the 7-year overall survival rate was 84%, with a median follow-up of 65 months. The transplant-related mortality was 12.5%. Conclusion. Allo-HSCT is considered as an alternative method of therapy for young patients with aggressive MM. Allo-HSCT in MM in some cases leads to long-term immunological control of the tumor.

Allogeneic Stem Cell Transplantation in Patients with High-Risk Multiple Myeloma: Utopia or Continuous Challenge in Aiming for Cure?

OPINION STATEMENT

Nowadays, several novel agents have been introduced in the treatment of multiple myeloma, not only resulting in high response rates and prolonged survival but also offering good quality of life. However, the potential of cure, especially for patients with advanced or unfavorable disease features, remains elusive. Allogeneic hematopoietic stem cell transplantation, based mainly on the graft vs. myeloma effect, can offer prolonged disease control and probability of cure but unfortunately at the cost of considerable transplant-related toxicity rates. Therefore, the role of allogeneic hematopoietic stem cell transplantation in the treatment of multiple myeloma has been called into question. Recently, several studies, particularly those with long-term follow-up, demonstrated a trend of survival superiority for allografted patients with high-risk disease. These data fuel again the interest in allogeneic stem cell transplantation for selected patients with high-risk multiple myeloma, especially if the high remission rates which can be achieved with the currently used treatment protocols could be long-life sustained through the additional exploitation of the long-lasting anti-multiple myeloma effect, originating from the allograft.

Long-term outcome after allogeneic stem cell transplantation in multiple myeloma

The role of allogeneic hematopoietic stem cell transplantation (allo-SCT) in multiple myeloma is controversial. We analyzed the results of 205 patients transplanted in one center during 2000-2017. Transplantation was performed on 75 patients without a previous autologous SCT (upfront-allo), on 74 as tandem transplant (auto-allo), and on 56 patients after relapse. Median overall survival (OS) was 9.9 years for upfront-allo, 11.2 years for auto-allo, and 3.9 years for the relapse group (p = 0.015). Progression-free survival (PFS) was 2.4, 2.4, and 0.9 years, respectively (p < 0.001). Non-relapse mortality at 5 years was 8% overall, with no significant difference between the groups. Post-relapse survival was 4.1 years for upfront-allo and auto-allo, and 2.6 years for the relapse group (p = 0.066). Survival of high-risk patients was reduced. In multivariate analysis, the auto-allo group had improved OS and chronic graft-versus-host disease was advantageous in terms of PFS, OS, and relapse incidence. Late relapses occurred in all groups. Allo-SCT resulted in long-term survival in a small subgroup of patients. Our results indicate that auto-allo-SCT is feasible and could be considered for younger patients in the upfront setting.

Allogeneic hematopoietic cell transplantation with non-myeloablative conditioning for patients with hematologic malignancies: Improved outcomes over two decades

We have used a non-myeloablative conditioning regimen for allogeneic hematopoietic cell transplantation for the past twenty years. During that period, changes in clinical practice have been aimed at reducing morbidity and mortality from infections, organ toxicity, and graft-versus-host disease. We hypothesized that improvements in clinical practice led to better transplantation outcomes over time. From 1997-2017, 1,720 patients with hematologic malignancies received low-dose total body irradiation +/- fludarabine or clofarabine before transplantation from HLA-matched sibling or unrelated donors, followed by mycophenolate mofetil and a calcineurin inhibitor ± sirolimus. We compared outcomes in three cohorts by year of transplantation: 1997 +/- 2003 (n=562), 2004 +/- 2009 (n=594), and 2010 +/- 2017 (n=564). The proportion of patients ≥60 years old increased from 27% in 1997 +/- 2003 to 56% in 2010-2017, and with scores from the Hematopoietic Cell Transplantation Comborbidity Index of ≥3 increased from 25% in 1997 +/- 2003 to 45% in 2010 +/- 2017. Use of unrelated donors increased from 34% in 1997 +/- 2003 to 65% in 2010-2017. When outcomes from 2004 +/- 2009 and 2010-2017 were compared to 1997 +/- 2003, improvements were noted in overall survival (P=.0001 for 2004-2009 and P <.0001 for 2010-2017), profression-free survival (P=.002 for 2004-2009 and P <.0001 for 2010 +/- 2017), non-relapse mortality (P<.0001 for 2004 +/- 2009 and P <.0001 for 2010 +/- 2017), and in rates of grades 2 +/- 4 acute and chronic graft-vs.-host disease. For patients with hematologic malignancies who underwent transplantation with non-myeloablative conditioning, outcomes have improved during the past two decades. Trials reported are registered under ClinicalTrials.gov identifiers: NCT00003145, NCT00003196, NCT00003954, NCT00005799, NCT00005801, NCT00005803, NCT00006251, NCT00014235, NCT00027820, NCT00031655, NCT00036738, NCT00045435, NCT00052546, NCT00060424, NCT00075478, NCT00078858, NCT00089011, NCT00104858, NCT00105001, NCT00110058, NCT00397813, NCT00793572, NCT01231412, NCT01252667, NCT01527045.

Hematopoeitic Cell Transplantation and CAR T-Cell Therapy: Complements or Competitors?

Allogeneic hematopoietic cell transplantation (allo-HCT) and chimeric antigen receptor T cell (CAR T) therapy are the main modalities of adoptive cellular immunotherapy that have widely permeated the clinical space. The advent of both technologies revolutionized treatment of many hematologic malignancies, both offering the chance at sustained remissions for patients who would otherwise invariably succumb to their diseases. The understanding and exploitation of the nonspecific alloreactivity of allo-HCT and the graft-versus-tumor effect is contrasted by the genetically engineered precision of CAR T therapy. Historically, those with relapsed and refractory hematologic malignancies have often been considered for allo-HCT, although outcomes vary dramatically and are associated with potential acute and chronic toxicities. Such patients, mainly with B-lymphoid malignancies, may now be offered CAR T therapy. Yet, a lack of prospective data to guide decisions thereafter requires individualized approaches on whether to proceed to allo-HCT or observe. The continued innovations to make CAR T therapy more effective and accessible will continue to alter such approaches, but similar innovations in allo-HCT will likely result in similarly improved clinical outcomes. In this review, we describe the history of the two platforms, dissect the clinical indications emphasizing their intertwining and competitive roles described in trials and practice guidelines, and highlight innovations in which they complement or inform one another.

Allogeneic Hematopoietic Transplantation for Multiple Myeloma in the New Drugs Era: A Platform to Cure

Allogeneic hematopoietic cell transplantation (alloHCT) represents a treatment option for multiple myeloma (MM) patients. As shown in several studies, alloHCT is highly effective, but it is hampered by a high toxicity, mainly related to the graft-versus-host disease (GVHD), a complex immunological reaction ascribable to the donor’s immune system. The morbidity and mortality associated with GVHD can weaken the benefits of this procedure. On the other side, the high therapeutic potential of alloHCT is also related to the donor’s immune system, through immunological activity known as the graft-versus-myeloma effect. Clinical research over the past two decades has sought to enhance the favorable part of this balance, along with the reduction in treatment-related toxicity. Frontline alloHCT showed promising results and a potential for a cure in the past. Currently, thanks to the improved results of first-line therapies and the availability of effective second- or third-line salvage therapies, alloHCT is reserved for selected high-risk patients and is considered a clinical option. For donor lymphocyte infusion, bortezomib or lenalidomide have been used as consolidation or maintenance therapies post-transplant—none has become standard of care. For those patients who relapse, the best treatment should be evaluated considering the patient’s clinical status and the previous lines of therapy. The use of newer drugs, such as monoclonal antibodies or other immunotherapies in the post-transplant setting, deserves further investigation. However, acceptable toxicity and a synergic effect with the newer immune system could be hopefully expected.

Newly diagnosed multiple myeloma patients treated with tandem auto-allogeneic stem cell transplant have better overall survival with similar outcomes at time of relapse compared to patients who received autologous transplant only

BACKGROUND

Long-term survival in patients progressing after tandem autologous-allogeneic stem cell transplant (SCT) has been reported, suggesting a persistent graft-vs-myeloma (GvM) effect even after post-transplant progression.

METHODS

In order to confirm this observation, we updated the results of our previously published cohort of 92 newly diagnosed myeloma patients who received tandem transplant and compared them with 81 contemporary patients who received autologous transplant only.

RESULTS

With a median follow-up of 13.1 and 10.2 years, respectively, median overall survival (OS) in the tandem group has not been reached, compared with 6.1 years after auto-SCT (P ≤ .001). Disease progression occurred less frequently after tandem transplant, with an estimated 10-year cumulative incidence of 49% vs 76% (P ≤ .001). Cumulative incidence of extensive chronic graft-vs-host disease (cGVHD) was high at 83%, with modest benefits on OS (60% vs 49%, P = .550) but sharp improvement of progression-free survival (PFS; 55% vs 10%, P = .002) at 10 years associated with development of cGVHD. After first progression, median OS was 5.8 years in tandem and 5.2 years in the auto-group (P = .062); median PFS was also similar.

CONCLUSION

Despite confirmation of better outcomes after upfront tandem transplant, our data do not support persistence of a strong, clinically significant graft-vs-myeloma effect after first progression, emphasizing the need to better characterize the GvM effect.

Allogenic stem cell transplantation in multiple myeloma: dead or alive and kicking?

Multiple myeloma (MM) accounts for about 1.8% of all cancers and slightly over 17% of hematologic malignancies. Despite improvements in outcomes in recent years, currently, there is still no cure for this disease. Although allogeneic stem cell transplantation (Allo-SCT) is a potentially curative treatment, given the armamentarium of highly effective therapeutic options and a pipeline of novel agents, many opinion leaders sustain that there is no longer a role for this approach. Of note, several studies that did not include novel agents reported long-term molecular remissions, and possibly a cure, in a subset of patients after reduced-intensity conditioning/nonmyeloablative (RIC/NM) Allo-SCT. However, there are no current data supporting upfront Allo-SCT. Prospective trials combining the so-called "graft-versus-myeloma" effect and new drugs are an unmet medical need in high-risk patients. Early relapse after first-line treatment, which identifies patients with poor prognosis independently of other prognostic factors, could become a clinical indication.

Long-term survival of 1338 MM patients treated with tandem autologous vs. autologous-allogeneic transplantation

Contrary to tandem autologous transplant (auto-auto), autologous followed by reduced intensity conditioning allogenic transplantation (auto-allo) offers graft-versus-myeloma (GVM) effect but with higher toxicity. Trials comparing these two strategies relied on availability of HLA-matched sibling donors for arm allocation (biological randomization) and yielded conflicting results. A pooled analysis of multiple trials with extended follow up provides an opportunity to compare these strategies. We obtained individual patient data from participants of four trials comparing auto-auto vs. auto-allo after induction therapy. There were 899 patients in auto-auto and 439 in auto-allo. Median follow up of survivors was 118.5 months. Median overall survival (OS) was 78.0 months in auto-auto and 98.3 months in auto-allo (HR = 0.84, P = 0.02). OS was 36.4% vs. 44.1% at 10 years (P = 0.01) for auto-auto and auto-allo, respectively. Progression-free survival was also improved in auto-allo (HR = 0.84, P = 0.004). Risk of non-relapse mortality was higher in auto-allo (10 year 8.3% vs. 19.7%, P < 0.001), while risk of disease progression was higher in auto-auto (10 year 77.2% vs. 61.6%, P < 0.001). Median post relapse survival was 41.5 months in auto-auto and 62.3 months in auto-allo (HR = 0.71, P < 0.001). This supports the existence of durable GVM effect enhancing myeloma control with subsequent therapies.

Allogeneic hematopoietic cell transplantation for multiple myeloma: A retrospective analysis of the Polish Myeloma Group

PURPOSE

In this multicenter retrospective analysis of the Polish Myeloma Group we assessed the real-life application of allogeneic transplantations (alloHCT) in multiple myeloma (MM) outside clinical trials in Poland.

METHODS

Anonymized clinical data of patients who underwent alloHCT were retrospectively collected from eight transplant centers and analyzed to identify factors affecting the outcome.

RESULTS

Sixty patients (34 males, 26 females) at median age of 45 (22-59) years who received alloHCT between 1993 and 2016 were included. In this group, 16 (27%) patients underwent myeloablative conditioning and 44 (73%) reduced-intensity conditioning alloHCT. Acute graft versus host disease (GvHD) occurred in 27 (45%) patients, while chronic GvHD was diagnosed in 13 (22%) patients. With the median observation time after alloHCT of 10 months, the relapse rate was 38%. Median progression-free survival (PFS) reached 9 months (0-183) while median overall survival (OS) was 23 months (0-183). Main causes of death included disease progression in 16 (43%), infections in 10 (27%), and GvHD in 7 patients (19%). Presence of chronic GvHD was the only factor associated with prolonged PFS (28 vs. 6 months; p = 0.05), however its impact on OS was not statistically significant (73 vs. 8 months; p = 0.09).

CONCLUSIONS

In this relatively small and heterogeneous study we observed that alloHCT was associated with high risk of severe complications, but resulted in long-term survival in a proportion of patients. Decisions on optimal indications and timing of the alloHCT in MM need to be taken in the broader context of reported outcomes including data from large studies.

The Global State of Hematopoietic Cell Transplantation for Multiple Myeloma: An Analysis of the Worldwide Network of Blood and Marrow Transplantation Database and the Global Burden of Disease Study

Multiple myeloma (MM) is a plasma cell neoplasm characterized by destructive bony lesions, anemia, and renal impairment. Access to effective therapy is limited globally. We report the rates and utilization of hematopoietic cell transplantation (HCT) globally from 2006-2015 to better characterize access to HCT for patients with MM. This was an analysis of a retrospective survey of Worldwide Network of Blood and Marrow Transplant sites, conducted annually between 2006-2015. Incidence estimates were from the Global Burden of Disease study. Outcome measures included total number of autologous and allogeneic HCTs by world regions, and percentage of newly diagnosed MM patients who underwent HCT, calculated by the number of transplants per region in calendar year/gross annual incidence of MM per region. From 2006 to 2015, the number of autologous HCT performed worldwide for MM increased by 107%. Utilization of autologous HCT was highest in Northern America and European regions, increasing from 13% to 24% in Northern America, and an increase from 15% to 22% in Europe. In contrast, the utilization of autologous HCT was lower in the Africa/Mediterranean region, with utilization only changing from 1.8% in 2006 to 4% in 2015. The number of first allogeneic HCT performed globally for MM declined after a peak in 2012 by -3% since 2006. Autologous HCT utilization for MM has increased worldwide in high-income regions but remains poorly utilized in Africa and the East Mediterranean. More work is needed to improve access to HCT for MM patients, especially in low to middle income countries. © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Chimeric antigen receptor T cell therapy in multiple myeloma: promise and challenges

Despite a sea change in the therapeutic landscape, multiple myeloma (MM), a cancer of antibody producing plasma cells, remains incurable requiring continued intervention for disease control. In this context, chimeric antigen receptor (CAR) T cell therapy has emerged as a promising immunotherapeutic approach with unprecedented results in heavily treated relapsed and/or refractory MM patients. Although B cell maturation antigen (BCMA) is the current lead target for CAR-T cell therapy in MM, several other antigenic targets are also being investigated. Relapses, however, are inevitable in spite of the promising early responses, and may be mediated by antigenic modulation, poor persistence and "immunostat" in tumor microenvironment. Akin to multi-agent chemotherapy, multi-targeted CAR-T antigens and combinatorial approaches are underway to overcome the resistance mechanisms. Further, CAR-T specific toxicity concerns such as cytokine release syndrome and neurotoxicity, as well as manufacturing time lag are other key challenges. Allogeneic CAR that offers "off-the-shelf" options, and mRNA transfected CAR are being developed to mitigate the access and safety issues. In this review we provide the comprehensive review of the most current clinical trial data for CAR-T in myeloma, challenges associated with this therapy and discuss its future in myeloma therapeutics.

Prognostic Factors for Postrelapse Survival after ex Vivo CD34+-Selected (T Cell-Depleted) Allogeneic Hematopoietic Cell Transplantation in Multiple Myeloma

Allogeneic hematopoietic cell transplantation (alloHCT) for multiple myeloma (MM), with its underlying graft-versus-tumor capacity, is a potentially curative approach for high-risk patients. Relapse is the main cause of treatment failure, but predictors for postrelapse survival are not well characterized. We conducted a retrospective analysis to evaluate predictors for postrelapse overall survival (OS) in 60 MM patients who progressed after myeloablative T cell-depleted alloHCT. The median patient age was 56 years, and 82% had high-risk cytogenetics. Patients received a median of 4 lines of therapy pre-HCT, and 88% achieved at least a partial response (PR) before alloHCT. Of the 38% who received preemptive post-HCT therapy, 13 received donor lymphocyte infusions (DLIs) and 10 received other interventions. Relapse was defined as very early (<6 months; 28%), early (6 to 24 months; 50%), or late (>24 months; 22%). At relapse, 27% presented with extramedullary disease (EMD). The median postrelapse overall survival (OS) by time to relapse was 4 months for the very early relapse group, 17 months for the early relapse group, and 72 months for the late relapse group (P = .002). Older age, relapse with EMD, <PR before alloHCT, <PR by day +100, and no maintenance were prognostic for inferior postrelapse OS on univariate analysis. On multivariate analysis adjusted for age and sex, very early relapse (hazard ratio [HR], 4.37; 95% confidence interval [CI], 1.42 to 13.5), relapse with EMD (HR, 5.20; 95% CI, 2.10 to 12.9), and DLI for relapse prevention (HR, .11; 95% CI, 2.10 to 12.9) were significant predictors for postrelapse survival. Despite their shared inherent high-risk status, patients with MM have significantly disparate post-HCT relapse courses, with some demonstrating long-term survival despite relapse.

90Y-labeled anti-CD45 antibody allogeneic hematopoietic cell transplantation for high-risk multiple myeloma

To improve disease control without increasing the toxicity of a reduced-intensity allogeneic hematopoietic cell transplantation (HCT) in multiple myeloma (MM), a phase I trial was performed using an antibody-radionuclide conjugate targeting CD45 (⁹⁰Y-DOTA-BC8) as conditioning. ⁹⁰Y-DOTA-BC8 was combined with fludarabine and low-dose TBI followed by allogeneic HCT in patients with MM and ≥1 adverse risk characteristic at diagnosis, relapse after autologous transplant, or plasma cell leukemia (PCL). The primary objective was to estimate the maximum tolerated radiation absorbed dose. Fourteen patients were treated (one with PCL, nine failed prior autologous HCT, and nine with ≥1 adverse cytogenetics). Absorbed doses up to 32 Gy to liver were delivered. No dose-limiting toxicities occurred. Non-hematologic toxicities were manageable and included primarily gastrointestinal (43%) and metabolic/electrolyte disturbances (36%). Treatment-related mortality at 100 days was 0%. At a median follow-up of 5 years, the overall survival was 71% (median not reached) and the progression-free survival was 41% (median 40.9 months). The incorporation of CD45-targeted radioimmunotherapy (RIT) into a reduced-intensity allogeneic HCT is well-tolerated and may induce long-term remissions among patients with poor-risk MM, supporting further development of RIT-augmented conditioning regimens for HCT.

Allogeneic Transplantation in Multiple Myeloma-Does It Still Have a Place?

Novel drugs have improved survival for patients with multiple myeloma in recent years. However, the disease is still fatal. Allogeneic stem cell transplantation (Allo) has proven to cure some patients with the disease, but its role is controversial due to relatively high transplant-related toxicity and mortality (nonrelapse mortality, NRM). Using nonmyeloablative reduced-intensity conditioning (RIC), both toxicity and NRM can be reduced, and RICAllo is, therefore, an option for subgroups of patients. Upfront tandem autologous/RICAllo (Auto/RICAllo) was shown to be superior to single Auto or tandem Auto/Auto in both progression-free (PFS) and overall survival (OS) in two prospective studies with long-term follow-up, while three similarly designed studies did not detect a difference. A recent update of pooled patient data from four of these studies showed significantly superior PFS and OS with Auto/RICAllo. Importantly, none of these studies showed inferior results with Auto/RICAllo in patients less than 70 years of age. Auto/RICAllo appears to overcome some poor risk cytogenetic markers. Encouraging results have also been seen in treatment of relapsed patients. Combining Allo with new proteasome inhibitors and immunomodulatory drugs may further improve results. Other encouraging new cell therapies such as with CAR T-cells, NK- and CAR NK-cells may well have a place in combination with RICAllo. Such studies are warranted.

Engineering Strategies to Enhance TCR-Based Adoptive T Cell Therapy

T cell receptor (TCR)-based adoptive T cell therapies (ACT) hold great promise for the treatment of cancer, as TCRs can cover a broad range of target antigens. Here we summarize basic, translational and clinical results that provide insight into the challenges and opportunities of TCR-based ACT. We review the characteristics of target antigens and conventional αβ-TCRs, and provide a summary of published clinical trials with TCR-transgenic T cell therapies. We discuss how synthetic biology and innovative engineering strategies are poised to provide solutions for overcoming current limitations, that include functional avidity, MHC restriction, and most importantly, the tumor microenvironment. We also highlight the impact of precision genome editing on the next iteration of TCR-transgenic T cell therapies, and the discovery of novel immune engineering targets. We are convinced that some of these innovations will enable the field to move TCR gene therapy to the next level.

Multiple myeloma: 2020 update on diagnosis, risk-stratification and management

DISEASE OVERVIEW

Multiple myeloma accounts for approximately 10% of hematologic malignancies.

DIAGNOSIS

The diagnosis requires ≥10% clonal bone marrow plasma cells or a biopsy proven plasmacytoma plus evidence of one or more multiple myeloma defining events (MDE) namely CRAB (hypercalcemia, renal failure, anemia, or lytic bone lesions) features felt related to the plasma cell disorder, bone marrow clonal plasmacytosis ≥60%, serum involved/uninvolved free light chain (FLC) ratio ≥100 (provided involved FLC is ≥100 mg/L), or >1 focal lesion on magnetic resonance imaging (MRI).

RISK STRATIFICATION

The presence of del(17p), t(4;14), t(14;16), t(14;20), gain 1q, or p53 mutation is considered high-risk multiple myeloma. Presence of any two high risk factors is considered double-hit myeloma; three or more high risk factors is triple-hit myeloma.

RISK-ADAPTED INITIAL THERAPY

In transplant eligible patients, induction therapy consists of bortezomib, lenalidomide, dexamethasone (VRd) given for approximately 3-4 cycles followed by autologous stem cell transplantation (ASCT). In high-risk patients, daratumumab, bortezomib, lenalidomide, dexamethasone (Dara-VRd) is an alternative to VRd. Selected standard risk patients can get additional cycles of induction, and delay transplant until first relapse. Patients not candidates for transplant are typically treated with VRd for approximately 8-12 cycles followed by lenalidomide; alternatively these patients can be treated with daratumumab, lenalidomide, dexamethasone (DRd).

MAINTENANCE THERAPY

After ASCT, standard risk patients need lenalidomide maintenance, while bortezomib-based maintenance is needed for patients with high-risk myeloma.

MANAGEMENT OF REFRACTORY DISEASE

Most patients require a triplet regimen at relapse, with the choice of regimen varying with each successive relapse.

Long-Term Follow-up of CALGB (Alliance) 100001: Autologous Followed by Nonmyeloablative Allogeneic Transplant for Multiple Myeloma

CALGB (Alliance) 100001 was a phase II study evaluating autologous stem cell transplant (ASCT) followed by nonmyeloablative allogeneic stem cell transplant (alloSCT) in patients with multiple myeloma who had received no more than 18 months of prior therapy and had experienced no more than 1 prior progression event. Conditioning for ASCT was with high-dose melphalan (200 mg/m²). The alloSCT reduced-intensity conditioning (RIC) regimen consisted of fludarabine (30 mg/m²/d i.v. on days -7 through -3) and cyclophosphamide (1 g/m²/d i.v. on days -4 through -3). The primary objective was to determine the 6-month post-alloSCT treatment-related mortality (TRM) rate. Additional objectives included determining the proportion of patients who could complete this tandem ASCT-alloSCT approach in a cooperative group setting, overall response rates, rates of donor chimerism, rates of graft-versus-host disease (GVHD), disease-free survival, and overall survival (OS). Sixty patients were enrolled, of whom 57 (95%) completed ASCT and 49 (82%) completed tandem ASCT-alloSCT. The TRM rate was 2% (1/49; 90% confidence interval, 0.10% to 9.3%). Moderate to severe (grades 2 to 3) acute GVHD was observed in 13 of 49 alloSCT patients (27%). One patient died due to GVHD within 9 months of alloSCT. Twenty-seven of the 49 patients (55%) who underwent alloSCT reported chronic GVHD as either limited (15/49; 31%) or extensive (12/49; 24%) in the first year post-alloSCT and prior to the start of nonprotocol therapy for progressive disease. With a median follow-up for survival of 11 years, the median OS time is 6.6 years and the median time to disease progression is 3.6 years. Similar to other studies, this study confirmed that tandem ASCT/alloSCT is associated with durable disease control in a subset of patients. This study demonstrated the feasibility of performing tandem ASCT/alloSCT in a cooperative group setting and determined that a fludarabine/cyclophosphamide RIC regimen is associated with a very low TRM rate.

Tandem Autologous-Autologous versus Autologous-Allogeneic Hematopoietic Stem Cell Transplant for Patients with Multiple Myeloma: Long-Term Follow-Up Results from the Blood and Marrow Transplant Clinical Trials Network 0102 Trial

Allogeneic hematopoietic cell transplant (HCT) may improve long-term multiple myeloma (MM) control through the graft-versus-myeloma effect. The Blood and Marrow Transplant Clinical Trials Network 0102 trial was a biologic assignment trial comparing tandem autologous transplant (auto-auto) versus autologous followed by reduced-intensity allogeneic (auto-allo) transplant in patients with newly diagnosed MM with standard-risk (n = 625) or high-risk (n = 85; β2-microglobulin at diagnosis ≥ 4 mg/dL or deletion of chromosome 13 by conventional karyotyping) disease. Although the initial 3-year analysis showed no difference in progression-free survival (PFS) between arms in either risk group, we hypothesized that long-term follow-up may better capture the impact of the graft-versus-myeloma effect. Median follow-up of survivors was over 10 years. Among standard-risk patients there was no difference in PFS (hazard ratio [HR], 1.11; 95% confidence interval [CI], .93 to 1.35; P = .25) or OS (HR, 1.03; 95% CI, .82 to 1.28; P = .82). The 6-year PFS was 25% in the auto-auto arm versus 22% in the auto-allo arm (P = .32), and 6-year overall survival (OS) was 60% and 59%, respectively (P = .85). In the high-risk group, although there was no statistically significant difference in PFS (HR, .66; 95% CI, .41 to 1.07; P = .07) and OS (HR, 1.01; 95% CI, .60 to 1.71; P = .96), a reduction in 6-year risk of relapse of 77% versus 47% (P = .005) was reflected in better PFS of 13% versus 31% (P = .05) but similar OS, at 47% versus 51% (P = .69). Allogeneic HCT can lead to long-term disease control in patients with high-risk MM and needs to be explored in the context of modern therapy.

Mass spectrometry-based identification of a B-cell maturation antigen-derived T-cell epitope for antigen-specific immunotherapy of multiple myeloma

The B-cell maturation antigen (BCMA) is currently being evaluated as promising tumor-associated surface antigen for T-cell-based immunotherapy approaches, such as CAR T cells and bispecific antibodies, in multiple myeloma (MM). Cytotoxic T cells bearing BCMA-specific T-cell receptors might further allow targeting HLA-presented antigens derived from the intracellular domain of BCMA. By analyzing a mass spectrometry-acquired immunopeptidome dataset of primary MM samples and MM cell lines for BCMA-derived HLA ligands, we identified the naturally presented HLA-B*18-restricted ligand P(BCMA)B*18. Additionally, P(BCMA)B*18 was identified on primary CLL samples, thereby expanding the range for possible applications. P(BCMA)B*18 induced multifunctional BCMA-specific cells de novo from naïve CD8+ T cells of healthy volunteers. These T cells exhibited antigen-specific lysis of autologous peptide-loaded cells. Even in the immunosuppressive context of MM, we detected spontaneous memory T-cell responses against P(BCMA)B*18 in patients. By applying CTLA-4 and PD-1 inhibition in vitro we induced multifunctional P(BCMA)B*18-specific CD8+ T cells in MM patients lacking preexisting BCMA-directed immune responses. Finally, we could show antigen-specific lysis of autologous peptide-loaded target cells and even MM.1S cells naturally presenting P(BCMA)B*18 using patient-derived P(BCMA)B*18-specific T cells. Hence, this BCMA-derived T-cell epitope represents a promising target for T-cell-based immunotherapy and monitoring following immunotherapy in B-cell malignancy patients.

Hematopoietic stem cell transplantation for blood cancers in the era of precision medicine and immunotherapy

Hematopoietic stem cell transplantation (HCT) has been an integral component in the treatment of many hematologic malignancies. Since the development of HCT nearly 50 years ago, the role of this modality has evolved as newer treatment approaches have been developed and integrated into the standard of care. In the last decade, novel and highly active targeted therapies and immunotherapies have been approved for many hematologic malignancies, raising the question of whether HCT continues to retain its prominent role in the treatment paradigms of various hematologic malignancies. In this review, the authors have described the current role of autologous and allogeneic HCT in the treatment of patients with acute leukemias, aggressive B-cell lymphomas, and multiple myeloma and discussed how novel targeted therapies and immunotherapies have changed the potential need, timing, and goal of HCT in patients with these diseases.

Panobinostat and venetoclax enhance the cytotoxicity of gemcitabine, busulfan, and melphalan in multiple myeloma cells

Gemcitabine (Gem), busulfan (Bu), and melphalan (Mel) are used for hematopoietic stem cell transplantation. To further improve their efficacy, a preclinical study on their synergism with the histone deacetylase inhibitor panobinostat (Pano) and the BCL2 inhibitor venetoclax/ABT199 was performed. Multiple myeloma cell lines MM.1R and MC/CAR were exposed to ∼IC₂₀ levels of the drugs. Synergistic cytotoxicity was observed in cells exposed to the five-drug combination as indicated by combination indexes <1, supported by ∼86% inhibition of proliferation and ∼84% annexin V positivity in MM.1R and ∼58% inhibition of proliferation and ∼46% annexin V positivity in MC/CAR cells. Activation of the DNA damage response and apoptosis were suggested by a modest increase in the phosphorylation of ATM and its substrates; significant cleavage of PARP1, caspase 3, and heat shock protein 90; DNA fragmentation; mitochondrial membrane depolarization; and reactive oxygen species production. The five-drug combination significantly decreased the levels of PI3K, AKT, mTOR, RAPTOR, P-P70S6K, and eIF2α, with concomitant increases in P-AMPK and its substrate Tuberin/TSC2, suggesting that the mTOR signaling pathway was compromised. Endoplasmic reticulum stress through activation of the unfolded protein response was also observed as suggested by increases in the levels of calnexin, BiP/GRP78, ERO1-Lα, and protein disulfide isomerase, which may relate to venetoclax-mediated inhibition of BCL2 in the endoplasmic reticulum. This is the first report on the effects of a venetoclax-containing regimen on the unfolded protein response. These results provide a rationale to propose a clinical trial on use of Gem + Bu + Mel + Pano + Venetoclax as part of a conditioning regimen for multiple myeloma patients undergoing autologous hematopoietic stem cell transplantation.