Anti-BCMA CAR-T cell-based therapies and bispecific antibodies in the immunotherapy era: are we ready for this?

INTRODUCTION: Therapeutic strategies against multiple myeloma (MM) have evolved dramatically in recent decades, with unprecedent results in the treatment landscape, culminating in the recent incorporation of novel agents in the anti-myeloma armamentarium. AREAS COVERED: BCMA represents one of the most promising targets in MM and currently available immune approaches, either approved or under active investigation, are clearly showing their greater potential over standard regimens. In this context, immunotherapies based on chimeric antigen receptor (CAR)-engineered T-cells and bispecific antibodies (BsAbs) have taken center stage, being the ones that are yielding the most promising results in clinical trials. This review focuses on the current landscape of BsAbs and CAR-T, summarizing the latest advances and possible future developments. EXPERT OPINION: CAR-T and BsAbs anti-BCMA strategies represent breakthrough therapies against MM. However, their inclusion in clinical practice is almost feared, due to the associated limitations, some of which have been addressed here. Meanwhile, all the efforts should be focused on individualizing and choosing the most suitable candidates for each treatment and to understand how to combine, or sequence, these therapies to improve efficacy and minimize toxicity, especially for those patients with limited available treatment options.

A real-world retrospective-prospective analysis of efficacy and safety of combined ixazomib, lenalidomide, and dexamethasone in relapsed/refractory multiple myeloma: The northern Italy experience.

INTRODUCTION: Ixazomib, lenalidomide, and dexamethasone (IRd) have been approved for the treatment of relapsed/refractory multiple myeloma (RRMM) based on the results of the TOURMALINE-MM1. OBJECTIVES AND METHODS: We conducted a retrospective-prospective analysis of 106 RRMM patients (pts) treated with IRd in 21 centers in Northern Italy, with the aim to evaluate the efficacy and safety of IRd in real life. RESULTS: At IRd initiation, 34% of pts were aged ≥75 (median 72.5), 8.5% had an ECOG performance status ≥2, 54.7% of evaluable pts carried high-risk cytogenetic abnormalities [del17p and/or t(4;14) and/or t(14;16) and/or 1 g gain/amp], 60.2% had received ≥2 prior lines of therapy (pLoT), 57.5% were lenalidomide (Len)-exposed (including both Len-sensitive and Len-refractory pts), and 22% were Len-refractory. Main G ≥3 adverse events (AEs) were thrombocytopenia (16%) and neutropenia (12.3%). G ≥3 non-hematologic AEs included infections (9.4%) and GI toxicity (diarrhea 5.7%, hepatotoxicity 2.8%), VTE, skin rash, and peripheral neuropathy were mainly G1-2. The overall response rate was 56.4% (≥VGPR 30%). With a median follow-up of 38 m, median PFS (mPFS) was 16 m and the 1-year OS rate was 73%. By subgroup analysis, an extended PFS was observed for pts achieving ≥VGPR (mPFS 21.2 m), time from diagnosis to IRd ≥5 years (26.2 m), 1 pLoT (34.4 m), Len-naïve (NR), age ≥70 (20 m). In pts exposed to Len, non-refractory in any prior line and immediately prior to IRd, mPFS was 16 and 18 m, respectively. An inferior PFS was seen in Len-refractory pts (4.6 m). By multivariate analysis, independent predictors of PFS were age ≥70 (HR 0.6), time from diagnosis ≥5 years (HR 0.32), refractoriness to Len in any prior line (HR 3.33), and immediately prior (HR 4.31). CONCLUSION: IRd might be effective and safe in RRMM pts with an indolent disease, in early lines of treatment, and who proved Len-sensitive, independent of age, and cytogenetic risk.

Daratumumab, Bortezomib, Lenalidomide, and Dexamethasone for Multiple Myeloma.

BACKGROUND: Daratumumab, a monoclonal antibody targeting CD38, has been approved for use with standard myeloma regimens. An evaluation of subcutaneous daratumumab combined with bortezomib, lenalidomide, and dexamethasone (VRd) for the treatment of transplantation-eligible patients with newly diagnosed multiple myeloma is needed. METHODS: In this phase 3 trial, we randomly assigned 709 transplantation-eligible patients with newly diagnosed multiple myeloma to receive either subcutaneous daratumumab combined with VRd induction and consolidation therapy and with lenalidomide maintenance therapy (D-VRd group) or VRd induction and consolidation therapy and lenalidomide maintenance therapy alone (VRd group). The primary end point was progression-free survival. Key secondary end points were a complete response or better and minimal residual disease (MRD)-negative status. RESULTS: At a median follow-up of 47.5 months, the risk of disease progression or death in the D-VRd group was lower than the risk in the VRd group. The estimated percentage of patients with progression-free survival at 48 months was 84.3% in the D-VRd group and 67.7% in the VRd group (hazard ratio for disease progression or death, 0.42; 95% confidence interval, 0.30 to 0.59; P<0.001); the P value crossed the prespecified stopping boundary (P = 0.0126). The percentage of patients with a complete response or better was higher in the D-VRd group than in the VRd group (87.9% vs. 70.1%, P<0.001), as was the percentage of patients with MRD-negative status (75.2% vs. 47.5%, P<0.001). Death occurred in 34 patients in the D-VRd group and 44 patients in the VRd group. Grade 3 or 4 adverse events occurred in most patients in both groups; the most common were neutropenia (62.1% with D-VRd and 51.0% with VRd) and thrombocytopenia (29.1% and 17.3%, respectively). Serious adverse events occurred in 57.0% of the patients in the D-VRd group and 49.3% of those in the VRd group. CONCLUSIONS: The addition of subcutaneous daratumumab to VRd induction and consolidation therapy and to lenalidomide maintenance therapy conferred a significant benefit with respect to progression-free survival among transplantation-eligible patients with newly diagnosed multiple myeloma. (Funded by the European Myeloma Network in collaboration with Janssen Research and Development; PERSEUS ClinicalTrials.gov number, NCT03710603; EudraCT number, 2018-002992-16.).

Elotuzumab plus pomalidomide and dexamethasone in relapsed/refractory multiple myeloma: a multicenter, retrospective, real-world experience with 200 cases outside of controlled clinical trials.

In the ELOQUENT-3 trial, the combination of elotuzumab, pomalidomide and dexamethasone (EloPd) proved to have a superior clinical benefit over pomalidomide and dexamethasone with a manageable toxicity profile, leading to its approval for the treatment of patients with relapsed/refractory multiple myeloma (RRMM) who have received at least two prior therapies, including lenalidomide and a proteasome inhibitor. We report here a real-world experience of 200 cases of RRMM treated with EloPd in 35 Italian centers outside of clinical trials. In our dataset, the median number of prior lines of therapy was two, with 51% of cases undergoing autologous stem cell transplant and 73% having been exposed to daratumumab. After a median follow-up of 9 months, 126 patients had stopped EloPd, most of them (88.9%) because of disease progression. The overall response rate was 55.4%, a finding in line with the pivotal trial results. Regarding adverse events, the toxicity profile in our cohort was similar to that in the ELOQUENT-3 trial, with no significant differences between younger (<70 years) and older patients. The median progression-free survival was 7 months, which was shorter than that observed in ELOQUENT-3, probably because of the different clinical characteristics of the two cohorts. Interestingly, International Staging System stage III disease was associated with worse progression-free survival (hazard ratio=2.55). Finally, the median overall survival of our series was shorter than that observed in the ELOQUENT-3 trial (17.5 vs. 29.8 months). In conclusion, our real-world study confirms that EloPd is a safe and possible therapeutic choice for patients with RRMM who have received at least two prior therapies, including lenalidomide and a proteasome inhibitor.

Lenalidomide-based triplet regimens in first relapsed multiple myeloma patients: real-world evidence from a propensity score matched analysis.

Lenalidomide and dexamethasone (Rd)-based triplets, in particular carfilzomib-Rd (KRd) and daratumumab-Rd (DaraRd), represent a standard of care in lenalidomide-sensitive multiple myeloma (MM) patients in first relapse. Meta-analysis of randomized clinical trials (RCT), suggested better outcome with DaraRd. Trying to address this issue in clinical practice, we collected data of 430 consecutive MM patients addressed to Rd-based triplets in first relapse between January 2017 and March 2021. Overall, the most common used regimen was DaraRd, chosen in almost half of the cases (54.4%), followed by KRd (34.6%). Different triplets were used much less commonly. In an attempt to limit the imbalance of a retrospective analysis, we conducted a propensity score matching (PSM) comparison between DaraRd and KRd. After PSM, efficacy of DaraRd versus KRd was similar in terms of overall-response rate (ORR) (OR: 0.9, P=0.685) as well as of very good partial response (VGPR) or better (OR: 0.9, P=0.582). The median progression-free survival (PFS) was significantly longer for DaraRd (29.8 vs. 22.5 months; P=0.028). DaraRd was tolerated better, registering a lower rate of grade 3-4 non-hematological toxicity (OR: 0.4, P<0.001). With the limitations of any retrospective analysis, our real-life PSM comparison between DaraRd and KRd, in first-relapse MM patients, showed better tolerability and prolonged PFS of DaraRd, although with some gaps of performance, in particular of DaraRd, with respect to RCT. Carfilzomib-containing regimens, like KRd, still remain a valid second-line option in the emerging scenario of first-line daratumumab-based therapy.

Survival Risk Scores for Real-Life Relapsed/Refractory Multiple Myeloma Patients Receiving Elotuzumab or Carfilzomib In Combination With Lenalidomide and Dexamethasone as Salvage Therapy: Analysis of 919 Cases Outside Clinical Trials.

The present study aimed to develop two survival risk scores (RS) for overall survival (OS, SRS KRd/EloRd ) and progression-free survival (PFS, PRS KRd/EloRd ) in 919 relapsed/refractory multiple myeloma (RRMM) patients who received carfilzomib, lenalidomide, and dexamethasone (KRd)/elotuzumab, lenalidomide, and dexamethasone (EloRd). The median OS was 35.4 months, with no significant difference between the KRd arm versus the EloRd arm. In the multivariate analysis, advanced ISS (HR = 1.31; P = 0.025), interval diagnosis-therapy (HR = 1.46; P = 0.001), number of previous lines of therapies (HR = 1.96; P < 0.0001), older age (HR = 1.72; P < 0.0001), and prior lenalidomide exposure (HR = 1.30; P = 0.026) remained independently associated with death. The median PFS was 20.3 months, with no difference between the two strategies. The multivariate model identified a significant progression/death risk increase for ISS III (HR = 1.37; P = 0.002), >3 previous lines of therapies (HR = 1.67; P < 0.0001), older age (HR = 1.64; P < 0.0001), and prior lenalidomide exposure (HR = 1.35; P = 0.003). Three risk SRS KRd/EloRd categories were generated: low-risk (134 cases, 16.5%), intermediate-risk (467 cases, 57.3%), and high-risk categories (213 cases, 26.2%). The 1- and 2-year OS probability rates were 92.3% and 83.8% for the low-risk (HR = 1, reference category), 81.1% and 60.6% (HR = 2.73; P < 0.0001) for the intermediate-risk, and 65.5% and 42.5% (HR = 4.91; P < 0.0001) for the high-risk groups, respectively. Notably, unlike the low-risk group, which did not cross the median timeline, the OS median values were 36.6 and 18.6 months for the intermediate- and high-risk cases, respectively. Similarly, three PRS KRd/EloRd risk categories were engendered. Based on such grouping, 338 (41.5%) cases were allocated in the low-, 248 (30.5%) in the intermediate-, and 228 (28.0%) in the high-risk groups. The 1- and 2-year PFS probability rates were 71.4% and 54.5% for the low-risk (HR = 1, reference category), 68.9% and 43.7% (HR = 1.95; P < 0.0001) for the intermediate-risk, and 48.0% and 27.1% (HR = 3.73; P < 0.0001) for the high-risk groups, respectively. The PFS median values were 29.0, 21.0, and 11.7 months for the low-, intermediate-, and high-risk cases. This analysis showed 2.7- and 4.9-fold increased risk of death for the intermediate- and high-risk cases treated with KRd/EloRd as salvage therapy. The combined progression/death risks of the two categories were increased 1.3- and 2.2-fold compared to the low-risk group. In conclusion, SRS KRd/EloRd and PRS KRd/EloRd may represent accessible and globally applicable models in daily clinical practice and ultimately represent a prognostic tool for RRMM patients who received KRd or EloRd.

An N-glycosylation hotspot in immunoglobulin κ light chains is associated with AL amyloidosis.

Immunoglobulin light chain (AL) amyloidosis is caused by a small, minimally proliferating B-cell/plasma-cell clone secreting a patient-unique, aggregation-prone, toxic light chain (LC). The pathogenicity of LCs is encrypted in their sequence, yet molecular determinants of amyloidogenesis are poorly understood. Higher rates of N-glycosylation among clonal κ LCs from patients with AL amyloidosis compared to other monoclonal gammopathies indicate that this post-translational modification is associated with a higher risk of developing AL amyloidosis. Here, we exploited LC sequence information from previously published amyloidogenic and control clonal LCs and from a series of 220 patients with AL amyloidosis or multiple myeloma followed at our Institutions to define sequence and spatial features of N-glycosylation, combining bioinformatics, biochemical, proteomics, structural and genetic analyses. We found peculiar sequence and spatial pattern of N-glycosylation in amyloidogenic κ LCs, with most of the N-glycosylation sites laying in the framework region 3, particularly within the E strand, and consisting mainly of the NFT sequon, setting them apart with respect to non-amyloidogenic clonal LCs. Our data further support a potential role of N-glycosylation in determining the pathogenic behavior of a subset of amyloidogenic LCs and may help refine current N-glycosylation-based prognostic assessments for patients with monoclonal gammopathies.

Elotuzumab plus lenalidomide and dexamethasone in relapsed/refractory multiple myeloma: Extended 3-year follow-up of a multicenter, retrospective clinical experience with 319 cases outside of controlled clinical trials.

The combination of elotuzumab, lenalidomide, and dexamethasone (EloRd) enhanced the clinical benefit over Rd with a manageable toxicity profile in the ELOQUENT-2 trial, leading to its approval in relapsed/refractory multiple myeloma (RRMM). The present study is a 3-year follow-up update of a previously published Italian real-life RRMM cohort of patients treated with EloRd. This revised analysis entered 319 RRMM patients accrued in 41 Italian centers. After a median follow-up of 36 months (range 6-55), 236 patients experienced disease progression or died. Median progression-free survival (PFS) and overall survival (OS) were 18.4 and 34 months, respectively. The updated multivariate analyses showed a significant reduction of PFS and OS benefit magnitude only in cases with International Staging System stage III. Major adverse events included grade 3/4 neutropenia (18.5%), anemia (15.4%), lymphocytopenia (12.5%), and thrombocytopenia (10.7%), while infection rates and pneumonia were 33.9% and 18.9%, respectively. No new safety signals with longer follow-up have been observed. Of 319 patients, 245 (76.7%) reached at least a partial remission. A significantly lower response rate was found in patients previously exposed to lenalidomide. In conclusion, our study confirms that EloRd is a safe and effective regimen for RRMM patients, maintaining benefits across multiple unfavorable subgroups.

Adjusted comparison between elotuzumab and carfilzomib in combination with lenalidomide and dexamethasone as salvage therapy for multiple myeloma patients.

The lack of a randomized trial comparing carfilzomib (K) versus elotuzumab (Elo) associated with lenalidomide and dexamethasone (Rd) prompted us to assess the relative usefulness of one triplet over the other. Five independent retrospective cohorts of 883 relapsed/refractory multiple myeloma (RRMM) patients, including 300 EloRd and 583 KRd cases, outside clinical trials, entered this non-randomized comparison. KRd cohort accounted for a higher incidence of younger patients, cases with ≥3 lines of therapy, already exposed to lenalidomide, International Staging System (ISS) stage III, and abnormal lactic dehydrogenase (LDH) level compared with EloRd cohort. Moreover, cytogenetic risk categories, detected in roughly one-third of cases, were equally distributed between the two therapy arms. The probability of CR+VGPR response was significantly higher in KRd (n = 314, 53.9%) than in EloRd patients (n = 111, 37.0%). Likewise, the cumulative incidence function of CR+VGPR, taking into account the competitive risk of death, was significantly higher in KRd arm patients than those in the EloRd arm (p = .003). Moreover, KRd treatment significantly reduced the progression or death risk by 46% in an adjusted multivariate analysis (HR: 0.54, 95% CI 0.42-0.69, p < .0001). Finally, in an adjusted illness-progression/death model, the effect of KRd versus EloRd was of higher magnitude among those who achieved CR+VGPR (-39% hazard ratio reduction, p = .02) than among those who achieved < VGPR (-29% hazard ratio reduction, p = .007). With limitations characteristic to any retrospective analysis, this current clinical practice study's overall results demonstrated potential benefits of KRd therapy compared with EloRd. This observation may help the daily clinical practice.

A risk-stratification model based on the initial concentration of the serum monoclonal protein and MYD88 mutation status identifies a subset of patients with IgM monoclonal gammopathy of undetermined significance at high risk of progression to Waldenström macroglobulinaemia or other lymphoproliferative disorders.

IgM monoclonal gammopathies of undetermined significance (IgM MGUS) are associated with a risk of progression to Waldenström macroglobulinaemia (WM) or other lymphoproliferative disorders (LPD) of 1-2% per year. We analysed 176 consecutive patients with IgM MGUS to evaluate risk factors for progression. With a median follow-up of 83 months (1214 person-years), 15 patients (8·5%) progressed to WM (n = 14) or marginal zone lymphoma (n = 1). The rate of progression was 1·32% per year (95% confidence interval [CI] 0·80-2·20). The serum monoclonal protein concentration and the MYD88 mutation were independent risk factors for progression (Hazard ratio [HR] 23·3, 95% CI 2·0-273·3, P = 0·012 and HR 24·4, 95% CI 2·2-275·3, P = 0·010, respectively). The cumulative incidence of progression, while considering death as a competing event, was 11·6% at 5 years and 38·0% at 10 years in MYD88-mutated patients with a serum monoclonal protein of 10 g/l or higher, as compared with 0% at 5 years and 1·1% at 10 years for patients with none or one risk factor. This risk-stratification model is able to identify a subset of patients with IgM MGUS at high risk of progression to WM or LPD who deserve a lifelong follow-up.

Smoldering multiple myeloma: the role of different scoring systems in identifying high-risk patients in real-life practice.

We explore the predictive role of 2014-updated International Myeloma Working Group (IMWG) diagnostic criteria and of some of currently available risk models for progression to symptomatic myeloma when applied in our unselected population of 75 smoldering multiple myeloma (SMM) patients observed between 2000 and 2015. Risk scores including routinely used clinical parameters such as bone marrow plasmacell infiltration rate, immunoparesis, serum monoclonal component (sMC) value, and altered free light chain ratio (FLCr), were clinically useful to identify SMM patients at higher risk of progression. Time to myeloma progression in our ultra-high risk SMM according to IMWG diagnostic update criteria was very short (12.4 months). Our analysis identified as independent reliable predictors of progression altered FLCr as well as increasing plasma cell infiltration which are part of most commonly applied risk models. Waiting for new scoring systems, bone marrow evaluation and complete laboratory screening are still milestones for SMM management.

Is re-challenge still an option as salvage therapy in multiple myeloma? The case of REal-life BOrtezomib re-Use as secoND treatment for relapsed patients exposed frontline to bortezomib-based therapies (the REBOUND Study).

Therapeutic re-challenge is currently a debated issue in the field of multiple myeloma (MM), given the recent availability of several new drugs and combinations. However, very few specific evidences are available about bortezomib re-use at first relapse. This multicenter, observational, retrospective study enrolled 134 MM patients with significant response after bortezomib-based frontline regimens and who had received a first salvage treatment containing bortezomib at relapse. The overall response rate was 71%, including 40% partial responses, 24% very good partial responses, and 7% complete responses. Re-treatment was well-tolerated, with no significant new or unexpected toxicities observed. The median duration of second progression-free survival (PFS) was 15 months, while median PFS2 was 55 months. With a median follow-up of 56 months, overall survival was 94 months for the entire series, without significant differences between patients undergoing or not undergoing transplant procedures. This real-life survey indicates that re-treatment including bortezomib as a first salvage therapy could be still considered in MM patients achieving durable response after initial exposure to bortezomib.

Non-Secretory Myeloma: Ready for a new Definition?

Non-secretory myeloma is a rare myeloma subtype whose diagnosis, until a few years ago, was established by demonstration of monoclonal plasma cells ≥10% in the bone marrow and by negative results on serum and urine electrophoresis and immunofixation studies. However, this type of myeloma could be misdiagnosed if the workup does not include an accurate study of serum free light chain test since some of the patients diagnosed as non-secretory could be light chain only with small amounts monoclonal proteinuria. Due to this limit in classification, all the information available today, generally coming from retrospective studies including patients studied completely and incompletely, could be misleading. A new definition is, thus, needed to distinguish between the true non-secretory, with a possible better prognosis, and the other forms of oligo-secretory myeloma with a prognosis more similar to the secretory form of myeloma. With all the data of the literature, the availability of laboratory and radiological tools, times are mature to depict a new definition of nonsecretory myeloma that deserves a peculiar work up and different response evaluation and, may be, a different therapeutic approach.

The amyloidogenic light chain is a stressor that sensitizes plasma cells to proteasome inhibitor toxicity.

Systemic light chain (AL) amyloidosis is caused by the clonal production of an unstable immunoglobulin light chain (LC), which affects organ function systemically. Although pathogenic LCs have been characterized biochemically, little is known about the biology of amyloidogenic plasma cells (PCs). Intrigued by the unique response rates of AL amyloidosis patients to the first-in-class proteasome inhibitor (PI) bortezomib, we purified and investigated patient-derived AL PCs, in comparison with primary multiple myeloma (MM) PCs, the prototypical PI-responsive cells. Functional, biochemical, and morphological characterization revealed an unprecedented intrinsic sensitivity of AL PCs to PIs, even higher than that of MM PCs, associated with distinctive organellar features and expression patterns indicative of cellular stress. These consisted of expanded endoplasmic reticulum (ER), perinuclear mitochondria, and a higher abundance of stress-related transcripts, and were consistent with reduced autophagic control of organelle homeostasis. To test whether PI sensitivity stems from AL LC production, we engineered PC lines that can be induced to express amyloidogenic and nonamyloidogenic LCs, and found that AL LC expression alters cell growth and proteostasis and confers PI sensitivity. Our study discloses amyloidogenic LC production as an intrinsic PC stressor, and identifies stress-responsive pathways as novel potential therapeutic targets. Moreover, we contribute a cellular disease model to dissect the biology of AL PCs.

The possible role of burden of therapy on the risk of myeloma extramedullary spread.

Extramedullary relapse (EMR) represents a poor prognostic marker in the course of multiple myeloma (MM). We reviewed data from 329 patients, diagnosed between 2000 and 2010, without extramedullary disease at onset to explore possible risk factors for EMR. The median overall survival of our study cohort was 6.4 years. The risk of EMR was 28 % with a median time from diagnosis to first EMR of 2.2 years (0.2-9.1 years). Patients with soft tissue masses located in extra-osseous organs (EMR-S) showed the worst outcome, compared to those with tumor masses arising from adjacent bone (EMR-B) (median OS 1.6 vs 2.4 years, p = 0.006). In addition, patients with EMR-S showed a significant trend for further development of extramedullary masses in a very short time (3.7 vs 5.7 months for EMR-B, p = 0.043). Multivariate analysis failed to identify any clinically presenting features predictive for EMR. The occurrence of EMR was higher in patients with more complex treatment history, defined on the basis of longer treatment duration (≥6 vs <6 months) and on elevated number of treatment lines administered (>2 vs ≤2 lines) (HR = 4.5, p < 0.001 and HR = 9.0, p < 0.001, respectively, when one or both factors are present).In conclusion, increasing burden of treatment might be a possible risk factor for EMR. MM patients with multiple relapses should be comprehensively investigated including, when possible, a whole-body-targeted radiologic technique to accurately detect EMR. Treatment choice should take into account the very poor outcome for patients with soft tissue involvement.