Cure of multiple myeloma -- more hype, less reality

Minimal residual disease detection by next-generation sequencing in multiple myeloma: Promise and challenges for response-adapted therapy

Assessment of minimal residual disease (MRD) is becoming a standard diagnostic tool for curable hematological malignancies such as chronic and acute myeloid leukemia. Multiple myeloma (MM) remains an incurable disease, as a major portion of patients even in complete response eventually relapse, suggesting that residual disease remains. Over the past decade, the treatment landscape of MM has radically changed with the introduction of new effective drugs and the availability of immunotherapy, including targeted antibodies and adoptive cell therapy. Therefore, conventional serological and morphological techniques have become suboptimal for the evaluation of depth of response. Recently, the International Myeloma Working Group (IMWG) introduced the definition of MRD negativity as the absence of clonal Plasma cells (PC) with a minimum sensitivity of <10⁻⁵ either by next-generation sequencing (NGS) using the LymphoSIGHT platform (Sequenta/Adaptative) or by next-generation flow cytometry (NGF) using EuroFlow approaches as the reference methods. While the definition of the LymphoSIGHT platform (Sequenta/Adaptive) as the standard method derives from its large use and validation in clinical studies on the prognostic value of NGS-based MRD, other commercially available options exist. Recently, the LymphoTrack assay has been evaluated in MM, demonstrating a sensitivity level of 10⁻⁵, hence qualifying as an alternative effective tool for MRD monitoring in MM. Here, we will review state-of-the-art methods for MRD assessment by NGS. We will summarize how MRD testing supports clinical trials as a useful tool in dynamic risk-adapted therapy. Finally, we will also discuss future promise and challenges of NGS-based MRD determination for clinical decision-making. In addition, we will present our real-life single-center experience with the commercially available NGS strategy LymphoTrack-MiSeq. Even with the limitation of a limited number of patients, our results confirm the LymphoTrack-MiSeq platform as a cost-effective, readily available, and standardized workflow with a sensitivity of 10⁻⁵. Our real-life data also confirm that achieving MRD negativity is an important prognostic factor in MM.

Impact of Pre-transplant and Post-transplant Remission Status of Patients on Survival in Newly Diagnosed Multiple Myeloma

The overall survival (OS) in patients with multiple myeloma (MM) has increased in the last decade due to the introduction of proteasome inhibitors, immunomodulatory drugs and monoclonal antibodies as well as an extensive combination of autologous stem cell transplantation (ASCT) for suitable patients. The objective of this study was to examine the impact of pre-transplant and post-transplant remission status of patients on survival in newly diagnosed multiple myeloma. Two hundred and four patients with newly diagnosed MM who received an ASCT in our HSC transplant center at Hacettepe University Hospital between the years of 2001 and 2018 were evaluated in a retrospective manner. The median follow-up period was 35.9 months (range 4.2-206.4) for the entire group. The 5-year OS for pre-transplant remission status CR/VGPR patients and pre-transplant remission status PR or less patients were 79% and 68%, respectively (p = 0.09). The 5-year PFS for pre-transplant remission status CR/VGPR patients and pre-transplant remission status PR or less patients were 62% and 45%, respectively (p = 0.23). The 5-year OS for post-transplant remission status CR/VGPR group was 72% and for post-transplant remission status PR or less group was 60% (p = 0.02). The 5-year PFS in post-transplant remission status CR/VGPR patients was 48% and post-transplant remission status PR or less patients was 36% (p = 0.03). This study focuses on determination of survival outcome based on the best response obtained before and after ASCT and particularly highlights the significance of reaching CR and VGPR.

Allogeneic Hematopoietic Stem Cell Transplantation for Myeloma: Time for an Obituary or Not Just Yet!

The management of myeloma has evolved dramatically in the last two decades. High dose melphalan and autologous hematopoietic stem cell transplantation (HSCT) marked the beginning of this journey. This was followed by an explosion of novel agents which were approved for management of myeloma. Allogeneic HSCT which was deemed as the only curative option was largely abhorred due to high transplant-related mortality (TRM) until the advent of reduced intensity conditioning (RIC). An approach of tandem autologous and RIC-allogeneic transplantations has showed the best promise for cure for this condition, particularly for those with high-risk cytogenetics. Yet, allogeneic HSCT seems to have fallen out of favor due to the projected high TRM and late relapses, even though the alternatives do not offer a cure, but merely prolong survival. Offering an allogeneic HSCT as a final resort in unlikely to yield gratifying results. At the same time, allogeneic HSCT needs to evolve in a disease-specific manner to address the relevant concerns regarding TRM and relapse. With the introduction of effective GVHD prophylaxis in the form of post-transplantation cyclophosphamide, transplantation from a haploidentical family donor has become a reality. The challenge lies in segregating graft-vs-myeloma effect from a graft-versus-host effect. We discuss the pro-survival and anti-apoptotic pathways via CD28-CD86 interactions which confer survival advantages to myeloma cells and the possibility of disruption of this pathway in the context of haploidentical transplantation through the use of CTLA4Ig without incurring T cell alloreactivity.

Comparison of conditioning regimen toxicities among autologous stem cell transplantation eligible multiple myeloma patients: High-dose melphalan versus high-dose melphalan and bortezomib

Background Autologous hematopoietic stem cell transplantation (AHSCT) remains the standard of care for younger patients with multiple myeloma (MM). Currently, high-dose melphalan (HDM) is recommended as conditioning regimen before AHSCT. Preclinical data suggest that combining bortezomib and melphalan has synergistic effect against multiple myeloma cells. Bortezomib and HDM (Bor-HDM) combination as conditioning regimen has been investigated by many other investigators. Objective In this retrospective study, we aimed to compare transplant-related toxicities and hematologic recovery of HDM and Bor-HDM conditioning regimens. Method We retrospectively evaluated hematologic recovery and toxicity profile in patients with MM who received AHSCT with either HDM ( n = 114) or Bor-HDM ( n = 53) conditioning regimen. Results Nonhematologic toxicities were comparable between HDM and Bor-HDM conditioning regimen, except mucositis and diarrhea being more frequent in the Bor-HDM group. Neutrophil and platelet engraftment time and duration of hospital stay were significantly shorter for HDM regimen. Conclusions In this retrospective analysis, we observed engraftment kinetics and duration of hospitalization were significantly worse in Bor-HDM conditioning regimen with manageable toxicities. Randomized studies are needed to further compare Bor- HDM regimen to HDM in terms of response rates, toxicities, and transplant-related mortality.

The High Effect of Chemomobilization with High-Dose Etopside + Granulocyte-Colony Stimulating Factor in Autologous Hematopoietic Peripheral Blood Stem Cell Transplantation: A Single Center Experience

Autologous hematopoietic stem cell transplantation (auto-HSCT) provides hematopoietic support after high-dose chemotherapy and is the standard of care for patients with multiple myeloma (MM), chemo sensitive relapsed high or intermediate grade non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). However, yields of hematopoietic stem cells vary greatly between patients, and the optimal strategy to mobilize hematopoietic stem cells into peripheral blood for collection has not been defined yet. We investigated the efficacy and safety of chemo mobilization with an intermediate dose etoposide (VP-16; 200 mg/m² on days 1-3) and granulocyte-colony stimulating factor (G-CSF)(5 µg/kg twice daily from day 4 through the final day of collection). We reviewed our institutional experience with 91 patients (71 MM, 12 HL, 8 NHL) mobilized with this regimen. VP-16 + G-CSF resulted in successful mobilization in 95.55% of the patients (on one patient stem cell collection with plerixafor was applied), including 76 patients (83.52%) whose stem cells were collected successfully in a single day. Collection was managed between min. D8 and max. D17. Patient age, gender, exposure to previous irradiation and chemotherapy, previous mobilization attempts, and disease characteristics were not considered during selection. Adverse effects of the regimen included supportive transfusions and fevers requiring hospitalization or intravenous antibiotics. VP-16 and G-CSF appears to be a safe and effective mobilization regimen for patients with multiple myeloma, non-Hodgkin’s lymphoma and Hodgkin’s lymphoma undergoing autologous stem cell transplantation, producing excellent stem cell yield with the majority of patients requiring 1 day of apheresis.

Impact of pretransplant therapy and depth of disease response before autologous transplantation for multiple myeloma

Patients with multiple myeloma (MM) who are eligible for autologous stem cell transplantation (ASCT) typically receive a finite period of initial therapy before ASCT. It is not clear if patients with suboptimal (less than a partial) response to initial therapy benefit from additional alternative therapy with intent to maximize pretransplant response. We identified 539 patients with MM who had an ASCT after having achieved less than a partial response (PR) to first-line induction chemotherapy between 1995 and 2010. These patients were then divided into 2 groups: those who received additional salvage chemotherapy before ASCT (n = 324) and those who had no additional salvage chemotherapy immediately before ASCT (n = 215). Additional pretransplant chemotherapy resulted in deepening responses in 68% (complete response in 8% and PR in 60%). On multivariate analysis there was no impact of pretransplant salvage chemotherapy on treatment-related mortality, risk for relapse, progression-free survival, or overall survival. In conclusion, for patients achieving less than a PR to initial induction therapy, including with novel agent combinations, additional pre-ASCT salvage chemotherapy improved the depth of response and pre-ASCT disease status but was not associated with survival benefit.

Lenalidomide maintenance for high-risk multiple myeloma after allogeneic hematopoietic cell transplantation

Allogeneic hematopoietic cell transplantation (alloHCT) with reduced-intensity conditioning is an appealing option for patients with high-risk multiple myeloma (MM). However, progression after alloHCT remains a challenge. Maintenance therapy after alloHCT may offer additional disease control and allow time for a graft-versus-myeloma effect. The primary objective of this clinical trial was to determine the tolerability and safety profile of maintenance lenalidomide (LEN) given on days 1 to 21 of 28 days cycles, with intrapatient dose escalation during 12 months/cycles after alloHCT. Thirty alloHCT recipients (median age, 54 years) with high-risk MM were enrolled at 8 centers between 2009 and 2012. The median time from alloHCT to LEN initiation was 96 days (range, 66 to 171 days). Eleven patients (37%) completed maintenance and 10 mg daily was the most commonly delivered dose (44%). Most common reasons for discontinuation were acute graft-versus-host disease (GVHD) (37%) and disease progression (37%). Cumulative incidence of grades III to IV acute GVHD from time of initiation of LEN was 17%. Outcomes at 18 months after initiation of maintenance were MM progression, 28%; transplantation-related mortality, 11%; and progression-free and overall survival, 63% and 78%, respectively. The use of LEN after alloHCT is feasible at lower doses, although it is associated with a 38% incidence of acute GVHD. Survival outcomes observed in this high-risk MM population warrant further study of this approach.

Importance of achieving stringent complete response after autologous stem-cell transplantation in multiple myeloma

PURPOSE

To study the impact of achieving stringent complete response (sCR), an increasingly attainable goal, after autologous stem-cell transplantation (ASCT) in patients with multiple myeloma (MM).

PATIENTS AND METHODS

Maximal response rates were determined in 445 consecutive patients who underwent ASCT within 12 months of diagnosis of MM. The patients achieving varying degrees of complete response (CR) are the focus of our study.

RESULTS

One hundred and nine patients (25%) achieved sCR after ASCT. The median overall survival (OS) rate from the time of transplantation for patients attaining sCR was not reached (NR), in contrast to those patients achieving conventional complete response (CR; n = 37; OS, 81 months) or near CR (nCR; n = 91; OS, 60 months; P < .001). Five-year OS rates were 80%, 53%, and 47% for sCR, CR, and nCR, respectively. The median time to progression (TTP) from ASCT of patients achieving sCR was significantly longer (50 months) than TTP of patients achieving CR or nCR (20 months and 19 months, respectively). On multivariable analysis, post-ASCT response of sCR was an independent prognostic factor for survival (hazard ratio, 0.44; 95% CI, 0.25 to 0.80; versus CR; P = .008), in addition to proliferation rate, pre-ASCT cytogenetics, and performance status. OS rates of patients attaining sCR continued to remain superior at 2-year landmark (median, NR v 70 months for conventional CR group; P = .007).

CONCLUSION

Improved long-term outcome is seen after ASCT with achievement of sCR when compared with lesser degrees of responses. Myeloma trials reporting the response rates should identify patients achieving sCR and CR separately, owing to markedly disparate outcomes of the two categories.

Curability of multiple myeloma

Among 792 patients with multiple myeloma treated from 1987 to 2010 and assessed after 18 months, there were 167 patients with complete remission. For those 60 patients treated between 1987–1998 and with long followup, the latest relapse occurred after 11.8 years, so that 13 patients have remained in sustained complete remission for longer than 12 years (range 12–22 years). These results suggest that 3% of all patients treated during that period may be cured of multiple myeloma. In addition to immunofixation, more sensitive techniques for the detection of residual disease should be applied more consistently in patients with apparent complete remission in order to identify those with potential cure.

Bortezomib and dexamethasone for Japanese patients with relapsed and refractory multiple myeloma: a single center experience

Bortezomib is a novel proteasome inhibitor, which has shown high antimyeloma activity. APEX trial, phase III randomized study for relapsed or refractory myeloma established efficacy and feasibility of bortezomib. In our study, we retrospectively investigated 60 Japanese patients with relapsed or refractory multiple myeloma (MM) who underwent bortezomib and dexamethasone (BD) therapy in our institution. Overall response rate was 75%, including 7 cases (11.7%) of complete response and 13 cases (21.7%) of very good partial response. Stable disease and progressive disease were observed in 15 patients (25%). Major ≥ grade 3 adverse events were hematological toxicities and grade 3 non-hematological toxicities included appetite loss, diarrhea and peripheral neuropathy. BD therapy was well tolerated, and produced significant response in relapsed or refractory MM patients. Recently, many worldwide trials including bortezomib or other new agents are ongoing to evaluate its efficacy not only as a therapy for relapsed or refractory disease but also as a frontline therapy. Further investigations are required to define how to use new antimyeloma agents for Japanese MM patients.

Arsenic trioxide with ascorbic acid and high-dose melphalan: results of a phase II randomized trial

Arsenic trioxide (ATO) is synergistic with ascorbic acid (AA) and melphalan against myeloma both in vitro and in vivo. The aim of this randomized phase II trial was to determine the safety and efficacy of a combination of ATO, melphalan, and AA as preparative regimen in 48 patients undergoing autologous hematopoietic stem cell transplantation (ASCT) for multiple myeloma (MM). Forty-eight patients received melphalan 200 mg/m2 i.v. over 2 days and AA 1000 mg i.v. over 7 days in 3 treatment arms: no ATO (arm 1), ATO 0.15 mg/kg i.v. x 7 days (arm 2), and ATO 0.25 mg/kg i.v. x 7 days (arm 3). No dose-limiting toxicity, engraftment failure, or nonrelapse mortality (NRM) was seen in the first 100 days post-ASCT. Complete responses (CR) were seen in 12 of 48 patients (25%), with an overall response rate (ORR = CR + PR) of 85%. Median progression-free survival (PFS) was 25 months; median overall survival (OS) has not yet been reached. There was no significant difference in CR, PFS, or OS among the 3 treatment arms, and no adverse effect of ATO on melphalan pharmacokinetics. Addition of ATO + AA to high-dose melphalan is safe and well tolerated as a preparative regimen for MM.

CS1, a potential new therapeutic antibody target for the treatment of multiple myeloma

PURPOSE

We generated a humanized antibody, HuLuc63, which specifically targets CS1 (CCND3 subset 1, CRACC, and SLAMF7), a cell surface glycoprotein not previously associated with multiple myeloma. To explore the therapeutic potential of HuLuc63 in multiple myeloma, we examined in detail the expression profile of CS1, the binding properties of HuLuc63 to normal and malignant cells, and the antimyeloma activity of HuLuc63 in preclinical models.

EXPERIMENTAL DESIGN

CS1 was analyzed by gene expression profiling and immunohistochemistry of multiple myeloma samples and numerous normal tissues. HuLuc63-mediated antimyeloma activity was tested in vitro in antibody-dependent cellular cytotoxicity (ADCC) assays and in vivo using the human OPM2 xenograft model in mice.

RESULTS

CS1 mRNA was expressed in >90% of 532 multiple myeloma cases, regardless of cytogenetic abnormalities. Anti-CS1 antibody staining of tissues showed strong staining of myeloma cells in all plasmacytomas and bone marrow biopsies. Flow cytometric analysis of patient samples using HuLuc63 showed specific staining of CD138+ myeloma cells, natural killer (NK), NK-like T cells, and CD8+ T cells, with no binding detected on hematopoietic CD34+ stem cells. HuLuc63 exhibited significant in vitro ADCC using primary myeloma cells as targets and both allogeneic and autologous NK cells as effectors. HuLuc63 exerted significant in vivo antitumor activity, which depended on efficient Fc-CD16 interaction as well as the presence of NK cells in the mice.

CONCLUSIONS

These results suggest that HuLuc63 eliminates myeloma cells, at least in part, via NK-mediated ADCC and shows the therapeutic potential of targeting CS1 with HuLuc63 for the treatment of multiple myeloma.

Deletion of the Short Arm of Chromosome 1 (del 1p) is a Strong Predictor of Poor Outcome in Myeloma Patients Undergoing an Autotransplant

Several chromosomal abnormalities detected by conventional cytogenetic analysis have an adverse impact on the outcome in myeloma patients. A wide spectrum of abnormalities involving chromosomes 1, 13, 14, and 17 has been described. We analyzed the outcome of 83 patients with clonal cytogenetic abnormalities, who underwent high-dose therapy and autologous stem cell transplantation for multiple myeloma at our institution. Clonal abnormalities were detected at diagnosis by conventional cytogenetic analysis in 83 patients. Patients underwent a single autologous transplant between April 2000 and May 2005. Preparative regimen was high-dose melphalan alone (73), or a combination of topotecan, melphalan, and cyclophosphamide (TMC=10). The most commonly observed chromosomal abnormalities were deletion of chromosome 13 (32%), hyperdiploidy (21%), deletion of chromosome 1p (18%), and t (11; 14) in 7% patients. Median follow-up among surviving patients was 25.5 months. Median interval from diagnosis to autotransplant was 7.7 months (range: 2.5-52). Median progression-free survival (PFS) for the entire group was 19 months and the median overall survival (OS) was 52 months. On univariate analysis, both PFS and OS were significantly shorter in patients with deletion 1p (P=.001 and <.0001, respectively). Thirty-two patients whose cytogenetic abnormalities returned to normal prior to autotransplant had longer PFS and OS than patients with persistent abnormalities (P=.02 and .08, respectively). Deletion 1p is associated with a significantly shorter remission and survival in patients undergoing high-dose therapy and a single autologous transplant for myeloma.

High-dose therapy with single autologous transplantation versus chemotherapy for newly diagnosed multiple myeloma: A systematic review and meta-analysis of randomized controlled trials

Myeloablative high-dose therapy and single autologous stem cell transplantation (HDT) is frequently performed early in the course of multiple myeloma, supported by some randomized controlled trials (RCTs) indicating overall survival (OS) and progression-free survival (PFS) benefit compared with nonmyeloablative standard-dose therapy (SDT). Other RCTs, however, suggest variable benefit. We therefore undertook a systematic review and meta-analysis of all RCTs evaluating upfront HDT versus SDT in myeloma. The primary objective was to quantify OS benefit with HDT, with PFS benefit a secondary objective. Anticipating heterogeneity, sensitivity and subgroup analyses were undertaken to assess robustness of results. Assessment of harms (treatment-related mortality) was also undertaken. We searched the PubMed, Embase, and Cochrane Collection of Controlled Trials databases using the terms myeloma combined with autologous or transplant or myeloablative or stem cell. In total, 3407 articles were accessed, and 10 RCTs prospectively comparing upfront HDT with SDT, with > or =2-year follow-up, and reporting OS benefit on an intent-to-treat basis were identified. Two reviewers independently extracted study characteristics, interventions, and outcomes. Hazard ratios (with 95% confidence interval) were determined. Nine studies comprising 2411 patients were fully analyzed. Significant heterogeneity was present. The combined hazard of death with HDT was 0.92 (95% confidence interval, 0.74-1.13). The combined hazard of progression with HDT was 0.75 (95% confidence interval, 0.59-0.96). The totality of the randomized data indicates PFS benefit but not OS benefit for HDT with single autologous transplantation performed early in multiple myeloma. Sensitivity and subgroup analyses supported the findings and indicated that, contrary to current reimbursement criteria, PFS benefit with upfront HDT is not restricted to chemoresponsive myeloma. However, the overall risk of developing treatment-related mortality with HDT was increased significantly (odds ratio, 3.01; 95% confidence interval, 1.64-5.50). Hence, evaluating alternative therapeutic options upfront may also be reasonable.

Autologous stem cell transplantation is safe and feasible in elderly patients with multiple myeloma

Several clinical trials have shown the superiority of autologous stem cell transplantation over conventional dose therapy for patients with multiple myeloma. This treatment, however, is limited to younger patients (<65 years) owing to concerns about toxicity and treatment-related mortality (TRM) in older patients. We treated 26 elderly myeloma patients (>70 years), who received a preparative regimen of melphalan 200 mg/m2 (19 patients), melphalan 180 mg/m2 (six patients) or melphalan 140 mg/m2 (one patient). Twenty-two of the 26 patients were alive after a median follow-up of 25 months (range=8-74). Responses (complete+partial response) were seen in 20 patients (77%), five (19%) of which were complete responses. Median PFS was 24 months, whereas median OS has not been reached. Cumulative incidence of 100-day TRM was 0%. Three-year PFS and OS were 39% (range=16-61) and 65% (range=35-83), respectively. A low serum albumin (<3.5 g/dl) was associated with a shorter PFS (P=0.02). Patients with relapsed disease at transplant, and an interval of >12 months between diagnosis and autotransplant, had a shorter OS (P=0.0004 and 0.04). HDT and autologous transplant is safe and feasible in elderly myeloma patients.