Carfilzomib or bortezomib with melphalan-prednisone for transplant-ineligible patients with newly diagnosed multiple myeloma

Metabolic Changes Are Associated with Melphalan Resistance in Multiple Myeloma

Multiple myeloma is an incurable hematological malignancy that impacts tens of thousands of people every year in the United States. Treatment for eligible patients involves induction, consolidation with stem cell rescue, and maintenance. High-dose therapy with a DNA alkylating agent, melphalan, remains the primary drug for consolidation therapy in conjunction with autologous stem-cell transplantation; as such, melphalan resistance remains a relevant clinical challenge. Here, we describe a proteometabolomic approach to examine mechanisms of acquired melphalan resistance in two cell line models. Drug metabolism, steady-state metabolomics, activity-based protein profiling (ABPP, data available at PRIDE: PXD019725), acute-treatment metabolomics, and western blot analyses have allowed us to further elucidate metabolic processes associated with melphalan resistance. Proteometabolomic data indicate that drug-resistant cells have higher levels of pentose phosphate pathway metabolites. Purine, pyrimidine, and glutathione metabolisms were commonly altered, and cell-line-specific changes in metabolite levels were observed, which could be linked to the differences in steady-state metabolism of naïve cells. Inhibition of selected enzymes in purine synthesis and pentose phosphate pathways was evaluated to determine their potential to improve melphalan's efficacy. The clinical relevance of these proteometabolomic leads was confirmed by comparison of tumor cell transcriptomes from newly diagnosed MM patients and patients with relapsed disease after treatment with high-dose melphalan and autologous stem-cell transplantation. The observation of common and cell-line-specific changes in metabolite levels suggests that omic approaches will be needed to fully examine melphalan resistance in patient specimens and define personalized strategies to optimize the use of high-dose melphalan.

Liposomal Formulation of a Melphalan Lipophilic Prodrug: Studies of Acute Toxicity, Tolerability, and Antitumor Efficacy

BACKGROUND

Recently we developed a scalable scheme of synthesis of melphalan ester conjugate with 1,2-dioleoyl-sn-glycerol (MlphDG) and a protocol for the fabrication of its lyophilized liposomal formulation.

OBJECTIVE

Herein we compared this new convenient in use formulation of MlphDG with parent drug Alkeran® in rats concerning several toxicological parameters and evaluated its antitumor efficacy in the model of breast cancer in mice.

METHOD

Liposomes of approximately 100 nm in diameter, consisting of egg phosphatidylcholine, soybean phosphatidylinositol, and MlphDG, or placebo liposomes without the drug were produced by extrusion and lyophilized. Alkeran® or liposomes recovered by the addition of water were injected into the tail vein of animals. Clinical examination of rats consisted of detailed inspection of the behavior, general status, and hematological parameters. Mice with transplanted breast cancer WNT-1 were subjected to multiple treatments with the drugs; tumor growth inhibition was assessed, together with cellular immunity parameters.

RESULTS

Liposomes showed approximately two times lower acute toxicity and better tolerability than Alkeran® in terms of behavioral criteria. The toxic effects of liposomes on hemopoiesis were manifested at higher doses than in the case of Alkeran®, proportionally to the difference in LD50 values. The formulation inhibited tumor growth significantly more effectively than Alkeran®, delaying the start of the exponential growth phase and exhibiting no additional toxic effects toward bone marrow.

CONCLUSION

Lower toxicity of the liposomal formulation of MlphDG promises improved quality of life for cancer patients in need of treatment with melphalan. Presumably, the list of indications for melphalan therapy could be extended.

Dose intensity and treatment duration of bortezomib in transplant-ineligible newly diagnosed multiple myeloma

BACKGROUND

Bortezomib-related peripheral neuropathy (PN) affects a relevant proportion of multiple myeloma (MM) patients treated with melphalan, prednisone, and bortezomib (VMP). Empirical dose modifications have attempted to reduce toxicity without compromising efficacy.

PATIENTS AND METHODS

We retrospectively evaluated the dose-response and dose-toxicity relationships in 114 unselected untreated MM patients intended for treatment with VMP with subcutaneous bortezomib.

RESULTS

Sixty-two patients (54%) completed the 9 scheduled cycles. Median treatment duration was 48 weeks (range 1-57), cumulative bortezomib dose was 41.8 mg/m² (2.6-67.6) and median dose intensity was 1.0 mg/m² /wk (0.2-2.6). Median progression-free survival (PFS) and overall survival (OS) for the full cohort were 86 weeks (95%CI 77-104) and 209 weeks (95% CI 157-259) respectively. Patients who progressed <60 days after discontinuing bortezomib had received a significantly inferior mean cumulative dose, 34.6 mg/m² than the remaining individuals, 45.5 (P = .023). PFS was significantly improved for patients achieving a very good partial response (VGPR) or better (P = .00007). Additional variables with a prognostic impact on PFS on univariate analysis included completion of the 9 scheduled cycles (P = .00002), patients with at least 50 weeks of treatment (P = .02) and patients receiving a cumulative dose of at least 49 mg/m² (P = .05). Achievement of a VGPR (HR 0.23; 95%CI 0.12-0.46; P = .00002) and a cumulative dose of 49 mg/m² (HR 0.46, 95%CI 0.27-0.78; P = .003) were statistically independent prognostic factors for PFS. Toxicity-related treatment dose reductions occurred in 75 individuals (66%). PN was observed in 50 individuals (44.6%), grade 3 in 9 (8%). The only prognostic factor for emergence of PN in multivariate analysis was the presence of baseline PN.

CONCLUSIONS

Biweekly full-dose treatment in the first cycles has a major impact in depth of response. Depth of response, cumulative bortezomib dose, and treatment duration had an impact in prolongation of PFS.

Current and Novel Alkylators in Multiple Myeloma

A large number of novel treatments for myeloma have been developed and approved; however, alkylating drugs continue to be part of standard regimens. Additionally, novel alkylators are currently being developed. We performed a non-systematized literary search for relevant papers and communications at large conferences, as well as exploiting the authors' knowledge of the field, to review the history, current use and novel concepts around the traditional alkylators cyclophosphamide, bendamustine and melphalan and current data on the newly developed pro-drug melflufen. Even in the era of targeted treatment and personalized medicine, alkylating drugs continue to be part of the standard-of-care in myeloma, and new alkylators are coming to the market.

Real-world comparative effectiveness of triplets containing bortezomib (B), carfilzomib (C), daratumumab (D), or ixazomib (I) in relapsed/refractory multiple myeloma (RRMM) in the US

Multiple available combinations of proteasome inhibitors, immunomodulators (IMIDs), and monoclonal antibodies are shifting the relapsed/refractory multiple myeloma (RRMM) treatment landscape. Lack of head-to-head trials of triplet regimens highlights the need for real-world (RW) evidence. We conducted an RW comparative effectiveness analysis of bortezomib (V), carfilzomib (K), ixazomib (I), and daratumumab (D) combined with either lenalidomide or pomalidomide plus dexamethasone (Rd or Pd) in RRMM. A retrospective cohort of patients initiating triplet regimens in line of therapy (LOT) ≥ 2 on/after 1/1/2014 was followed between 1/2007 and 3/2018 in Optum's deidentified US electronic health records database. Time to next treatment (TTNT) was estimated using Kaplan-Meier methods; regimens were compared using covariate-adjusted Cox proportional hazard models. Seven hundred forty-one patients (820 patient LOTs) with an Rd backbone (VRd, n = 349; KRd, n = 218; DRd, n = 99; IRd, n = 154) and 348 patients (392 patient LOTs) with a Pd backbone (VPd, n = 52; KPd, n = 146; DPd, n = 149; IPd, n = 45) in LOTs ≥2 were identified. More patients ≥75 years received IRd (39.6%), IPd (37.8%), and VRd (36.7%) than other triplets. More patients receiving VRd/VPd were in LOT2 vs other triplets. Unadjusted median TTNT in LOT ≥ 2: VRd, 13.9; KRd, 8.7; IRd, 11.4; DRd, not estimable (NE); and VPd, 12.0; KPd, 6.7; IPd, 9.5 months; DPd, NE. In covariate-adjusted analysis, only KRd vs DRd was associated with a significantly higher risk of next LOT initiation/death (HR 1.72; P = 0.0142); no Pd triplet was significantly different vs DPd in LOT ≥ 2. Our data highlight important efficacy/effectiveness gaps between results observed in phase 3 clinical trials and those realized in the RW.

Renal failure among multiple myeloma patients utilizing carfilzomib and associated factors in the "real world"

Carfilzomib, a next-generation proteasome inhibitor, improves outcomes in patients with multiple myeloma (MM); however, a proportion of those treated develop renal failure due to adverse event, comorbidity, or myeloma progression. The rate of renal failure and associated risk factors remains unknown in real-world populations. Adults with relapsed/refractory MM who received carfilzomib between the years 2013 and 2016 were identified in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases. Renal failure was defined using the corresponding International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10) diagnostic codes and procedure codes for dialysis. Patients with a pre-existing diagnosis of renal failure were excluded to distinguish an adverse event from comorbidity. Multivariate cox regression analysis was performed to identify the variables independently associated with the development of renal failure among MM patients utilizing carfilzomib. A total of 1950 patients were included in the analysis. Renal failure developed in 22% of patients during the study period. The median time to development of renal failure from first carfilzomib administration was 1.6 months (range < 0.1-23.3). Increasing age (adjusted hazard ratio [aHR] 1.01 per year, p = 0.018), pre-existing heart failure (aHR 1.50, p = 0.005), and pre-existing chronic kidney disease (aHR 2.00, p < 0.001) were associated with a higher risk of developing renal failure. Renal failure occurred in up to 22% of patients on carfilzomib therapy. The exact cause and mechanism of renal failure cannot be determined from our study and may be multifactorial. Future studies are needed to further understand the cause of renal failure among patients on carfilzomib and devise strategies to mitigate the risk.

Carfilzomib or bortezomib in combination with cyclophosphamide and dexamethasone followed by carfilzomib maintenance for patients with multiple myeloma after one prior therapy: results from a multi-centre, phase II, randomized, controlled trial (MUKfive)

The proteasome inhibitors, carfilzomib and bortezomib, are widely used to treat myeloma but head-to-head comparisons have produced conflicting results. We compared the activity of these proteasome inhibitors in combination with cyclophosphamide and dexamethasone (KCd vs. VCd) in second-line treatment using fixed duration therapy and evaluated the efficacy of carfilzomib maintenance. MUKfive was a phase II controlled, parallel group trial that randomized patients (2:1) to KCd (n=201) or VCd (n=99); responding patients on carfilzomib were randomized to maintenance carfilzomib (n=69) or no further treatment (n=72). Primary endpoints were: (i) very good partial response (non-inferiority, odds ratio [OR] 0.8) at 24 weeks, and (ii) progression-free survival. More participants achieved a very good partial response or better with carfilzomib than with bortezomib (40.2% vs. 31.9%, OR=1.48, 90% confidence interval [CI]: 0.95, 2.31; non-inferior), with a trend for particular benefit in patients with adverse-risk disease. KCd was associated with higher overall response (partial response or better, 84.0% vs. 68.1%, OR=2.72, 90% CI: 1.62, 4.55, P=0.001). Neuropathy (grade ≥3 or ≥2 with pain) was more common with bortezomib (19.8% vs. 1.5%, P<0.0001), while grade ≥3 cardiac events and hypertension were only reported in the KCd arm (3.6% each). The median progression-free survival in the KCd arm was 11.7 months vs. 10.2 months in the VCd arm (hazard ratio [HR]=0.95, 80% CI: 0.77, 1.18). Carfilzomib maintenance was associated with longer progression-free survival, median 11.9 months vs. 5.6 months for no maintenance (HR 0.59, 80% CI: 0.46-0.77, P=0.0086). When used as fixed duration therapy in first relapase, KCd is at least as effective as VCd, and carfilzomib is an effective maintenance agent. This trial was registered with International Standard Randomised Controlled Trial Number (ISRCTN) identifier: ISRCTN17354232.

Evolution of Treatment Paradigms in Newly Diagnosed Multiple Myeloma

The plasma cell neoplasm multiple myeloma (MM) is currently considered incurable. However, significant advances in treatment options over the past 20 years have led to unprecedented response rates to initial therapy as well as prolonged survival rates. Induction regimens have evolved from alkylator-based therapies to those consisting of immunomodulatory drugs and proteasome inhibitors. The combination of bortezomib/lenalidomide/dexamethasone (VRd) has emerged as a standard regimen for both transplant-eligible (TE) and transplant-ineligible (TI) patient populations. More recent efforts have focused on the incorporation of monoclonal antibody therapy into the newly diagnosed setting, particularly anti-CD38 monoclonal antibodies. In the TI patient population, the combination of daratumumab/lenalidomide/dexamethasone is now considered another standard therapy. In the TE setting, it remains to be determined whether the addition of daratumumab to the VRd backbone results in improved long-term outcomes. Recent studies have confirmed the progression-free survival benefit of upfront autologous stem cell transplant and have established lenalidomide maintenance as a standard of care. Multiple studies are evaluating whether inclusion of monoclonal antibody therapy in the maintenance setting will improve outcomes. The optimal management of newly diagnosed patients with high-risk cytogenetics remains to be determined. We discuss the emerging therapies that will likely shape management of newly diagnosed MM in the future.

Immunomodulators in newly diagnosed multiple myeloma: current and future concepts

Introduction: Impressive therapeutic progress is being made in the management of multiple myeloma (MM). his progress is related to the introduction of several new classes of therapeutic agents including proteasome inhibitors, immunomodulatory drugs (IMiDs) and monoclonal antibodies (MoAbs).Areas covered: In this manuscript, the role of the IMiDs thalidomide and lenalidomide in the management of newly diagnosed MM is discussed. The mode of action of IMiDs and their role in the management of newly diagnosed MM patients is highlighted. In addition, clinical data on how MoAbs such as the anti-CD38 antibody daratumumab can further increase the efficacy of IMiD-based first-line anti-myeloma regimens are provided. A database search in PubMed was carried out.Expert Opinion: Immunomodulation has become an indispensable part of successful anti-myeloma regimens both at relapse and at diagnosis. The combination of lenalidomide plus dexamethasone with an anti-CD38 MoAb such as daratumumab and a proteasome inhibitor such as bortezomib is currently one of the most potent first-line treatment regimens for MM. A better understanding on how IMiDs synergize with existing and new anti-myeloma treatments can further improve the outcome for patients. Optimal first-line therapy will continue to benefit the long-term outcome of a growing population of young and elderly MM patients.

New regimens and directions in the management of newly diagnosed multiple myeloma

The introduction of novel agents over the last decade has rapidly expanded the therapeutic landscape of multiple myeloma (MM) for both transplant-eligible and transplant-ineligible patients. The assessment of minimal residual disease (MRD) by next-generation flow cytometry or next-generation sequencing is established as a powerful predictor of long-term outcomes. The use of MRD in response-adapted clinical trials may provide opportunities to identify candidates for treatment escalation and de-escalation. Agents with proven activity in the relapsed and refractory setting are being studied in the management of high-risk newly diagnosed MM (NDMM). Here, we summarize the most recent clinical trials that have led to the current paradigms in the management of NDMM. We also discuss how novel agents could be incorporated in the newly diagnosed setting and potential clinical trial designs that could leverage MRD information with the goal of treatment optimization.

Minimal residual disease negativity by next-generation flow cytometry is associated with improved organ response in AL amyloidosis

Light chain (AL) amyloidosis is caused by a small B-cell clone producing light chains that form amyloid deposits and cause organ dysfunction. Chemotherapy aims at suppressing the production of the toxic light chain (LC) and restore organ function. However, even complete hematologic response (CR), defined as negative serum and urine immunofixation and normalized free LC ratio, does not always translate into organ response. Next-generation flow (NGF) cytometry is used to detect minimal residual disease (MRD) in multiple myeloma. We evaluated MRD by NGF in 92 AL amyloidosis patients in CR. Fifty-four percent had persistent MRD (median 0.03% abnormal plasma cells). There were no differences in baseline clinical variables in patients with or without detectable MRD. Undetectable MRD was associated with higher rates of renal (90% vs 62%, p = 0.006) and cardiac response (95% vs 75%, p = 0.023). Hematologic progression was more frequent in MRD positive (0 vs 25% at 1 year, p = 0.001). Altogether, NGF can detect MRD in approximately half the AL amyloidosis patients in CR, and persistent MRD can explain persistent organ dysfunction. Thus, this study supports testing MRD in CR patients, especially if not accompanied by organ response. In case MRD persists, further treatment could be considered, carefully balancing residual organ damage, patient frailty, and possible toxicity.

Measurable residual disease in multiple myeloma and light chain amyloidosis: more than meets the eye

The emergence of highly effective multiple myeloma (MM) treatments may bring cure within reach and highlights the need for highly sensitive measurable residual disease (MRD) techniques to replace conventional response assessments. MRD is being incorporated as an endpoint in an increasing number of studies and had been repeatedly shown to be both a predictive marker of response to treatment and a prognostic marker for future relapse. However, those results should be cautiously interpreted due to non-uniform reporting and the need for longer follow up to assess for sustained MRD negativity. This review aims to critically analyze the key MRD aspects including the current evidence supporting the use of MRD in clinical practice and the pitfalls of the various methods used to assess MRD. The utility of MRD for light chain (AL) amyloidosis will also be discussed.

Renal insufficiency in multiple myeloma: a systematic review and meta-analysis of all randomized trials from 2005-2019

Clinical trials may be inconsistent in their enrollment and reporting of patients with multiple myeloma (MM) who have renal insufficiency (RI). We performed a systematic review of all MM randomized clinical trials (RCT) from 2005-2019 to evaluate reporting of prevalence, eligibility criteria and outcomes of patients with RI and MM. One-hundred and twenty-three RCTs were included. Only 30% of studies clearly reported on the proportion of patients who had RI. Only 68.2% reported eligibility criteria pertaining to RI, with no uniformity in the reported criteria. The relative risk (RR) of disease progression or death in patients with RI was higher than those without, RR of 1.20 (1.003-1.431) for relapsed/refractory and 1.07 (1.001-1.046) for newly diagnosed. There is inconsistent reporting and enrollment of patients with RI on MM RCT's. We advocate for higher enrollment of patients with RI and transparent reporting of their eligibility criteria and outcomes.

A comprehensive overview of daratumumab and carfilzomib and the recently approved daratumumab, carfilzomib and dexamethasone regimen in relapsed/refractory multiple myeloma

Introduction: Novel, effective regimens are needed in patients with relapsed and refractory myeloma (RRMM) who inevitably relapse after PI and IMID containing treatment. Areas covered: Pre-clinical data, early clinical and pivotal trials relevant to the development of the two backbone drugs of carfilzomib and daratumumab, and the two important recent trials, EQUULEUS and CANDOR leading to the FDA approval of the combination regimen of daratumumab, carfilzomib, and dexamethasone (DKd) for RRMM are detailed in this review. Expert opinion: EQUULEUS and CANDOR have established the efficacy of the DKd regimen in the landscape of bortezomib and lenalidomide refractory patients. The split dosing schedule of the first dose of daratumumab was approved by the FDA based on EQUULEUS, significantly improving patient convenience. Subcutaneous daratumumab is being evaluated in this combination to further improve tolerance and convenience. Further studies are needed to evaluate and optimally sequence the many effective and potent drugs available in RRMM.

A large meta-analysis establishes the role of MRD negativity in long-term survival outcomes in patients with multiple myeloma

The prognostic value of minimal residual disease (MRD) for progression-free survival (PFS) and overall survival (OS) was evaluated in a large cohort of patients with multiple myeloma (MM) using a systematic literature review and meta-analysis. Medline and EMBASE databases were searched for articles published up to 8 June 2019, with no date limit on the indexed database. Clinical end points stratified by MRD status (positive or negative) were extracted, including hazard ratios (HRs) on PFS and OS, P values, and confidence intervals (CIs). HRs were estimated based on reconstructed patient-level data from published Kaplan-Meier curves. Forty-four eligible studies with PFS data from 8098 patients, and 23 studies with OS data from 4297 patients were identified to assess the association between MRD status and survival outcomes. Compared with MRD positivity, achieving MRD negativity improved PFS (HR, 0.33; 95% CI, 0.29-0.37; P < .001) and OS (HR, 0.45; 95% CI, 0.39-0.51; P < .001). MRD negativity was associated with significantly improved survival outcomes regardless of disease setting (newly diagnosed or relapsed/refractory MM), MRD sensitivity thresholds, cytogenetic risk, method of MRD assessment, depth of clinical response at the time of MRD measurement, and MRD assessment premaintenance and 12 months after start of maintenance therapy. The strong prognostic value of MRD negativity and its association with favorable outcomes in various disease and treatment settings sets the stage to adopt MRD as a treatment end point, including development of therapeutic strategies. This large meta-analysis confirms the utility of MRD as a relevant surrogate for PFS and OS in MM.

A Tangle of Genomic Aberrations Drives Multiple Myeloma and Correlates with Clinical Aggressiveness of the Disease: A Comprehensive Review from a Biological Perspective to Clinical Trial Results

Multiple myeloma (MM) is a genetically heterogeneous disease, in which the process of tumorigenesis begins and progresses through the appearance and accumulation of a tangle of genomic aberrations. Several are the mechanisms of DNA damage in MM, varying from single nucleotide substitutions to complex genomic events. The timing of appearance of aberrations is well studied due to the natural history of the disease, that usually progress from pre-malignant to malignant phase. Different kinds of aberrations carry different prognostic significance and have been associated with drug resistance in some studies. Certain genetic events are well known to be associated with prognosis and are incorporated in risk evaluation in MM at diagnosis in the revised International Scoring System (R-ISS). The significance of some other aberrations needs to be further explained. Since now, few phase 3 randomized trials included analysis on patient's outcomes according to genetic risk, and further studies are needed to obtain useful data to stratify the choice of initial and subsequent treatment in MM.

Three Drug Combinations in the Treatment of Fit Elderly Multiple Myeloma Patients

The multiple myeloma (MM) non transplant eligible (NTE) population is growing in line with the aging of the population in Western countries. Historically, this population has been known for having a greater risk of treatment related toxicity, and therefore drug development was slow and rather oriented towards the improvement of safety profile than the optimization of disease control. However, NTE MM patients, at least for the fit/non frail patients in recent years, seemed to have benefited more from a less palliative care to improve the depth of response and then prolong survival. NTE MM being a quite heterogeneous population, there are still a number of groups of patients that are in need of more efficient therapy, avoiding unnecessary toxicity, particularly for the frail patients. The use of triplet regimen with a melphalan-prednisone (MP) backbone has long been the standard of care for NTE MM, often dedicated to non-frail patients. New standards of care, triplet, and even quadruplet combinations, are emerging on the basis of the MP backbone but also on the more recently approved lenalidomide-dexamethasone (Rd) backbone. These developments were largely possible in line with the development of antibody-based immunotherapies (IT) in MM. The objective to improve outcomes with an acceptable safety profile will see other key therapeutic developments such as the dropping of dexamethasone early in the disease course or various attempts to allow permanent treatment discontinuation with a prolonged disease control. In that context, it is possible that immunomonitoring, minimal residual disease (MRD), and genomic risk-adaptation will become key elements of the treatment decisions on triplet-based regimens.

Diagnostic and Therapeutic Challenges in the Management of Intermediate and Frail Elderly Multiple Myeloma Patients

Multiple myeloma (MM) mostly affects elderly patients, which represent a highly heterogeneous population. Indeed, comorbidities, frailty status and functional reserve may vary considerably among patients with similar chronological age. For this reason, the choice of treatment goals and intensity is particularly challenging in elderly patients, and it requires a multidimensional evaluation of the patients and the disease. In recent years, different tools to detect patient frailty have been developed, and the International Myeloma Working Group frailty score currently represents the gold standard. It identifies intermediate-fit and frail patients requiring gentler treatment approaches compared to fit patients, aiming to preserve quality of life and prevent toxicities. This subset of patients is underrepresented in clinical trials, and studies exploring frailty-adapted approaches are scarce, making the choice of therapy extremely challenging. Treatment options for intermediate-fit and frail patients might include dose-adapted combinations, doublets, and less toxic combinations based on novel agents. This review analyzes the available tools for the assessment of frailty and possible strategies to improve the discriminative power of the scores and expand their use in real-life and clinical trial settings. Moreover, it addresses the main therapeutic challenges in the management of intermediate-fit and frail MM patients at diagnosis and at relapse.

Old and new generation proteasome inhibitors in multiple myeloma

Proteasome inhibitors (PIs) represent a recently developed drug class that inhibit the ubiquitin-proteasome system, thus interfering with the intracellular machinery who has the duty of misfolded proteins disposal. Myeloma plasma cells are structurally aimed at the production of large quantities of immunoglobulins. This explains their vulnerability to any perturbation of intracellular protein homeostasis. Bortezomib is the first-in-class PI and nowadays, in combination with other compounds, is the cornerstone of multiple myeloma (MM) treatment in several settings. Bortezomib has several attractive features for its inclusion in the induction phase of therapy: high efficacy, rapid cytoreduction, absence of nephrotoxicity, fast reduction of plasmacytomas, and fast pain control. However, the safety profile of bortezomib is characterized by a not negligible peripheral neuropathy. Newer PIs, such as carfilzomib and ixazomib, have been developed and each offers specific advantages. Carfilzomib is extremely efficient in proteasome inhibition. This results in high efficacy but suffers from a significant cardiotoxicity. Ixazomib is the first oral PI with a proteasome inhibition profile similar to bortezomib, with lower neurotoxicity. PIs mechanism of action is complementary with other drug classes, and this explains the synergism between PIs and other drugs, in particular steroids and immunomodulators. PIs are frequently used in doublets and triplets. Also, they can be associated with anti-CD38 monoclonal antibodies. This review summarizes the principal biological and clinical features of PIs in the MM treatment.

Chemotherapy-based regimens in multiple myeloma in 2020

Multiple myeloma (MM) represents the second-most common hematologic malignancy. In the 1980s, induction therapy with alkylating agents, such as anthracyclines and steroids, as well as high-dose chemotherapy followed by autologous stem cell transplantation were the main therapeutic approaches for MM. Since the introduction of more effective drugs, such as proteasome inhibitors, immunomodulatory drugs, monoclonal antibodies and histone deacetylase inhibitor, the new therapeutic algorithm allows of achieving a significantly improvement of prognosis. Numerous regimens, which differently combine these new agents, have been developed and tested in clinical trials. The results of these new regimens are reported each year. In this variegated new contest, old chemotherapeutic drugs still maintain an overriding weight, especially when beneficially combined with new drugs. Also, this is particular true in specific situations, such as extramedullary manifestations, in which tumor mass reduction becomes an urgent clinical need, or in case of chemotherapy-induced stem-cell mobilization. Moreover, melphalan represents the gold standard conditioning regimen since 2002, either alone or, possibly in the next future, in combination with busulfan. Finally, new chemotherapeutic agents with new mechanisms of action, such as melflufen, are in early experimental phase.

Carfilzomib or bortezomib in combination with lenalidomide and dexamethasone for patients with newly diagnosed multiple myeloma without intention for immediate autologous stem-cell transplantation (ENDURANCE): a multicentre, open-label, phase 3, randomised, controlled trial

BACKGROUND

Bortezomib, lenalidomide, and dexamethasone (VRd) is a standard therapy for newly diagnosed multiple myeloma. Carfilzomib, a next-generation proteasome inhibitor, in combination with lenalidomide and dexamethasone (KRd), has shown promising efficacy in phase 2 trials and might improve outcomes compared with VRd. We aimed to assess whether the KRd regimen is superior to the VRd regimen in the treatment of newly diagnosed multiple myeloma in patients who were not being considered for immediate autologous stem-cell transplantation (ASCT).

METHODS

In this multicentre, open-label, phase 3, randomised controlled trial (the ENDURANCE trial; E1A11), we recruited patients aged 18 years or older with newly diagnosed multiple myeloma who were ineligible for, or did not intend to have, immediate ASCT. Participants were recruited from 272 community oncology practices or academic medical centres in the USA. Key inclusion criteria were the absence of high-risk multiple myeloma and an Eastern Cooperative Oncology Group performance status of 0-2. Enrolled patients were randomly assigned (1:1) centrally by use of permuted blocks to receive induction therapy with either the VRd regimen or the KRd regimen for 36 weeks. Patients who completed induction therapy were then randomly assigned (1:1) a second time to either indefinite maintenance or 2 years of maintenance with lenalidomide. Randomisation was stratified by intent for ASCT at disease progression for the first randomisation and by the induction therapy received for the second randomisation. Allocation was not masked to investigators or patients. For 12 cycles of 3 weeks, patients in the VRd group received 1·3 mg/m² of bortezomib subcutaneously or intravenously on days 1, 4, 8, and 11 of cycles 1-8, and day 1 and day 8 of cycles nine to twelve, 25 mg of oral lenalidomide on days 1-14, and 20 mg of oral dexamethasone on days 1, 2, 4, 5, 8, 9, 11, and 12. For nine cycles of 4 weeks, patients in the KRd group received 36 mg/m² of intravenous carfilzomib on days 1, 2, 8, 9, 15, and 16, 25 mg of oral lenalidomide on days 1-21, and 40 mg of oral dexamethasone on days 1, 8, 15, and 22. The coprimary endpoints were progression-free survival in the induction phase, and overall survival in the maintenance phase. The primary analysis was done in the intention-to-treat population and safety was assessed in patients who received at least one dose of their assigned treatment. The trial is registered with ClinicalTrials.gov, NCT01863550. Study recruitment is complete, and follow-up of the maintenance phase is ongoing.

FINDINGS

Between Dec 6, 2013, and Feb 6, 2019, 1087 patients were enrolled and randomly assigned to either the VRd regimen (n=542) or the KRd regimen (n=545). At a median follow-up of 9 months (IQR 5-23), at a second planned interim analysis, the median progression-free survival was 34·6 months (95% CI 28·8-37·8) in the KRd group and 34·4 months (30·1-not estimable) in the VRd group (hazard ratio [HR] 1·04, 95% CI 0·83-1·31; p=0·74). Median overall survival has not been reached in either group. The most common grade 3-4 treatment-related non-haematological adverse events included fatigue (34 [6%] of 527 patients in the VRd group vs 29 [6%] of 526 in the KRd group), hyperglycaemia (23 [4%] vs 34 [6%]), diarrhoea (23 [5%] vs 16 [3%]), peripheral neuropathy (44 [8%] vs four [<1%]), dyspnoea (nine [2%] vs 38 [7%]), and thromboembolic events (11 [2%] vs 26 [5%]). Treatment-related deaths occurred in two patients (<1%) in the VRd group (one cardiotoxicity and one secondary cancer) and 11 (2%) in the KRd group (four cardiotoxicity, two acute kidney failure, one liver toxicity, two respiratory failure, one thromboembolic event, and one sudden death).

INTERPRETATION

The KRd regimen did not improve progression-free survival compared with the VRd regimen in patients with newly diagnosed multiple myeloma, and had more toxicity. The VRd triplet regimen remains the standard of care for induction therapy for patients with standard-risk and intermediate-risk newly diagnosed multiple myeloma, and is a suitable treatment backbone for the development of combinations of four drugs.

FUNDING

US National Institutes of Health, National Cancer Institute, and Amgen.

Emerging drugs for the treatment of light chain amyloidosis

INTRODUCTION

Systemic AL amyloidosis is a protein-misfolding disorder that is characterized by the deposition of insoluble amyloid fibrils derived from kinetically unstable light chains. Achieving a rapid and deep hematologic response is critical for long-term survival.

AREAS COVERED

This review covers the existing and emerging treatment options for systemic AL, divided into anti-plasma cell and fibril-directed therapies. The anti-CD38 monoclonal antibody daratumumab has demonstrated an unprecedented hematologic response rate and will become the new standard-of-care in newly diagnosed patients in combination with CyBorD/VCD. Other plasma cell-directed drugs that have prospective data on safety and efficacy in AL include proteasome inhibitors [bortezomib and ixazomib], immunomodulatory drugs [lenalidomide and pomalidomide], and alkylating agents [melphalan and bendamustine]. A major unmet need is the development of fibril-directed therapies with the goal of eliminating amyloid fibrils that are already deposited in vital organs.

EXPERT OPINION

The treatment of newly diagnosed AL in the future will likely include daratumumab-based therapy in conjunction with fibril-directed therapy. The most promising second line drugs are venetoclax [for t(11;14)] and pomalidomide, with several others in the pipeline, including antibody-drug conjugates. Minimal residual disease will emerge as a new endpoint for drug development and will potentially guide treatment duration.

Frontline therapy for newly diagnosed patients with multiple myeloma

Since the introduction of an alkylator to the treatment of multiple myeloma (MM), new effective agents have been developed, such as immunomodulatory drugs including thalidomide, lenalidomide, and pomalidomide; proteasome inhibitors including bortezomib, carfilzomib, and ixazomib; monoclonal antibodies including daratumumab and elotuzumab; and deacetylase inhibitors including panobinostat. Numerous regimens with these new agents have been developed and they have contributed in improving survival outcomes in MM patients. In addition, the recommended therapies for newly diagnosed MM change every year based on the results of clinical trials. This review will discusses the appropriate induction therapies based on recent clinical trials for patients with newly diagnosed MM.

Measurable residual disease in multiple myeloma: ready for clinical practice?

The landscape of multiple myeloma (MM) has changed considerably in the past two decades regarding new treatments, insight into disease biology and innovation in the techniques available to assess measurable residual disease (MRD) as the most accurate method to evaluate treatment efficacy. The sensitivity and standardization achieved by these techniques together with unprecedented rates of complete remission (CR) induced by new regimens, raised enormous interest in MRD as a surrogate biomarker of patients' outcome and endpoint in clinical trials. By contrast, there is reluctance and general lack of consensus on how to use MRD outside clinical trials. Here, we discuss critical aspects related with the implementation of MRD in clinical practice.

Treatment and disease-related complications in multiple myeloma: Implications for survivorship

New treatments have transformed multiple myeloma into a chronic disease. Hence, optimal management of treatment and disease-related complications remains a critical component of survivorship care. Survivorship care model in cancers requiring a fixed-duration therapy may not be applicable to myeloma, since patients are exposed to multiple lines of continuous therapy along the disease trajectory. The two most common therapy-related causes of death, which require special consideration, are infection and second cancers. Identifying patients at a high risk of toxicities will facilitate individualized treatment selection and designing clinical trials for protective strategies targeting those patients. For example, prophylactic antibiotic or immunoglobulin replacement can be tested for primary prevention of infections in high-risk patients. Long-term follow up of ongoing trials and epidemiologic data will help identify the nature and trajectory of rare toxicities with a long latency, such as secondary cancers. Patients who are frail, have persistent renal insufficiency, and refractory to multiple lines of therapy need special attention regarding treatment toxicity and quality of life. In this review, we discuss the incidence, risk-factors, and management of treatment and disease-related complications in myeloma, discuss knowledge gaps and research priorities in this area, and propose a survivorship care model to improve health-care delivery to a growing pool of myeloma survivors.

Proteasome inhibition in multiple myeloma: lessons for other cancers

Cellular protein homeostasis (proteostasis) depends on the controlled degradation of proteins that are damaged or no longer required by the ubiquitin-proteasome system (UPS). The 26S proteasome is the principal executer of substrate-specific proteolysis in eukaryotic cells and regulates a myriad of cellular functions. Proteasome inhibitors were initially developed as chemical tools to study proteasomal function but rapidly became widely used anticancer drugs that are now used at all stages of treatment for the bone marrow cancer multiple myeloma (MM). Here, we review the mechanisms of action of proteasome inhibitors that underlie their preferential toxicity to MM cells, focusing on endoplasmic reticulum stress, depletion of amino acids, and effects on glucose and lipid metabolism. We also discuss mechanisms of resistance to proteasome inhibition such as autophagy and metabolic rewiring and what lessons we may learn from the success and failure of proteasome inhibition in MM for treating other cancers with proteostasis-targeting drugs.

Pursuing a Curative Approach in Multiple Myeloma: A Review of New Therapeutic Strategies

Multiple myeloma (MM) is still considered an incurable hematologic cancer and, in the last decades, the treatment goal has been to obtain a long-lasting disease control. However, the recent availability of new effective drugs has led to unprecedented high-quality responses and prolonged progression-free survival and overall survival. The improvement of response rates has prompted the development of new, very sensitive methods to measure residual disease, even when monoclonal components become undetectable in patients' serum and urine. Several scientific efforts have been made to develop reliable and validated techniques to measure minimal residual disease (MRD), both within and outside the bone marrow. With the newest multidrug combinations, a good proportion of MM patients can achieve MRD negativity. Long-lasting MRD negativity may prove to be a marker of "operational cure", although the follow-up of the currently ongoing studies is still too short to draw conclusions. In this article, we focus on results obtained with new-generation multidrug combinations in the treatment of high-risk smoldering MM and newly diagnosed MM, including the potential role of MRD and MRD-driven treatment strategies in clinical trials, in order to optimize and individualize treatment.

Predicting venous thromboembolism in multiple myeloma: development and validation of the IMPEDE VTE score

Venous thromboembolism (VTE) is a common cause of morbidity and mortality among patients with multiple myeloma (MM). The International Myeloma Working Group (IMWG) developed guidelines recommending primary thromboprophylaxis, in those identified at high-risk of VTE by the presence of risk factors. The National Comprehensive Cancer Network (NCCN) has adopted these guidelines; however, they lack validation. We sought to develop and validate a risk prediction score for VTE in MM and to evaluate the performance of the current IMWG/NCCN guidelines. Using 4446 patients within the Veterans Administration Central Cancer Registry, we used time-to-event analyses to develop a risk score for VTE in patients with newly diagnosed MM starting chemotherapy. We externally validated the score using the Surveillance, Epidemiology, End Results (SEER)-Medicare database (N = 4256). After identifying independent predictors of VTE, we combined the variables to develop the IMPEDE VTE score (Immunomodulatory agent; Body Mass Index ≥25 kg/m2 ; Pelvic, hip or femur fracture; Erythropoietin stimulating agent; Dexamethasone/Doxorubicin; Asian Ethnicity/Race; VTE history; Tunneled line/central venous catheter; Existing thromboprophylaxis). The score showed satisfactory discrimination in the derivation cohort, c-statistic = 0.66. Risk of VTE significantly increased as score increased (hazard ratio 1.20, P = <.0001). Within the external validation cohort, IMPEDE VTE had a c-statistic of 0.64. For comparison, when evaluating the performance of the IMWG/NCCN guidelines, the c-statistic was 0.55. In summary, the IMPEDE VTE score outperformed the current IMWG/NCCN guidelines and could be considered as the new standard risk stratification for VTE in MM.

Minimal Residual Disease Status as a Surrogate Endpoint for Progression-free Survival in Newly Diagnosed Multiple Myeloma Studies: A Meta-analysis

BACKGROUND

Therapeutic advances have greatly extended survival times in patients with multiple myeloma, necessitating increasingly lengthy trials when using survival outcomes as primary endpoints. A surrogate endpoint that can more rapidly predict survival could accelerate drug development. We conducted a meta-analysis to evaluate minimal residual disease (MRD) status as a valid progression-free survival (PFS) surrogate in patients with newly diagnosed multiple myeloma (NDMM).

MATERIALS AND METHODS

We searched abstracts in PubMed, The American Society of Hematology, and the European Hematology Association for "myeloma," "minimal residual disease," and "clinical trial." Because of the need to evaluate the treatment effect on MRD response, only randomized studies for subjects with NDMM were included. Details on the MRD-tested populations were required. The meta-analysis was performed by principles outlined at the 2013 United States Food and Drug Administration workshop on MRD in acute myeloid leukemia.⁴² For samples that were not measured for MRD and within the subset specified for MRD assessment, their MRD status was imputed from the samples that had known MRD status. Patients that were excluded from planned MRD assessment were considered MRD-positive.

RESULTS

Six randomized studies, representing 3283 patients and 2208 MRD samples, met analysis inclusion criteria. MRD negativity rates ranged from 0.06 to 0.70. The treatment effect on the odds ratio for MRD-negative response strongly correlated with the hazard ratio for PFS with a coefficient of determination for the weighted regression line of 0.97. Our meta-analysis suggested that MRD status met both the Prentice criteria for PFS surrogacy.

CONCLUSIONS

These results support the claim that MRD status can be used as a surrogate for PFS in NDMM.

Estimation of minimally important differences and responder definitions for EORTC QLQ-MY20 scores in multiple myeloma patients

Objectives

Thresholds for the minimally important difference (MID) or responder definition (RD) in health‐related quality‐of‐life (HRQoL) scores are required to interpret the impact of an intervention or change in the trajectory of the condition which is meaningful to patients. This study aimed to establish MID and RD for the European Organisation for Research and Treatment of Cancer Quality of Life Multiple Myeloma questionnaire (EORTC QLQ‐MY20).

Methods

A novel mixed‐methods approach was applied by utilizing both existing clinical trial data and prospective patient interviews. Anchor‐based, distribution‐based, and qualitative‐based estimates of meaningful change were triangulated to form recommended RDs for each scale of the EORTC QLQ‐MY20. Anchor‐based MIDs were summarized using weighted correlation.

Results

Recommended MIDs were as follows: Disease Symptoms (DS 10 points), Side Effects of Treatment (SE 10 points), Body Image (BI 13 points), and Future Perspective (FP 9 points). Recommended RDs were as follows: DS (16 improvement; 11 worsening), SE (6 improvement; 9 worsening), BI (33 improvement; 33 worsening), and FP (11 improvement; 11 worsening).

Conclusions

The study generated estimates of the MID and RD for each scale of the EORTC QLQ‐MY20. Published estimates will enable investigators and clinicians to adopt these as standard for interpretation and for hypothesis testing. Consequently, analyses from trials of different interventions can be more comparable.