Multiple myeloma refractory to lenalidomide: A systematic literature review of trials and real-world evidence.

The growing use of frontline lenalidomide treatment in multiple myeloma (MM) is increasing the proportion of lenalidomide-refractory patients, which may limit the efficacy of subsequent lines of treatment (LOT). This systematic literature review (January 2008-October 2023) of clinical trials (CT) and real-world studies (RW) assessed treatment outcomes in adults with relapsed/refractory MM (RRMM) who were previously treated with ≥1 LOT, progressed and were lenalidomide-refractory. Medline, EMBASE and additional electronic databases were searched for articles published in English. Primary outcomes included progression-free survival (PFS), overall survival (OS) and overall/objective response rate (ORR); 24 CT and 19 RW were included. For CT, the population-weighted mean of median PFS (CT = 14) and OS (CT = 6) were shorter in the lenalidomide-refractory cohort (months: 8.8 [n = 2699] and 21.7 [n = 1066], respectively) than the intent-to-treat population (months: 13.8 [n = 5380] and 35.9 [n = 2264], respectively); the population-weighted (N = 2142) mean ORR for lenalidomide-refractory patients (CT = 18) was 56.0%. RW reported considerable variation in PFS (RW = 7), OS (RW = 8) and ORR (RW = 8); and median PFS (RW = 2; months) was lower in lenalidomide/bortezomib-refractory (5.5/5.5; n = 81/n = 25) versus lenalidomide-refractory (7.3/8.0; n = 81/n = 61) patients. These data provide evidence that clinical trials and real-world outcomes are suboptimal in lenalidomide-refractory patients with RRMM, highlighting the need to improve treatment options for this population.

Targeting Ikaros and Aiolos: reviewing novel protein degraders for the treatment of multiple myeloma, with a focus on iberdomide and mezigdomide.

INTRODUCTION: The treatment of multiple myeloma (MM) is evolving rapidly. Quadruplet regimens incorporating proteasome inhibitors, immunomodulatory drugs (IMiDs), and CD38 monoclonal antibodies have emerged as standard-of-care options for newly diagnosed MM, and numerous novel therapies have been approved for relapsed/refractory MM. However, there remains a need for novel options in multiple settings, including refractoriness to frontline standards of care. AREAS COVERED: Targeting degradation of IKZF1 and IKZF3 - Ikaros and Aiolos - through modulation of cereblon, an E3 ligase substrate recruiter/receptor, is a key mechanism of action of the IMiDs and the CELMoD agents. Two CELMoD agents, iberdomide and mezigdomide, have demonstrated substantial preclinical and clinical activity in MM and have entered phase 3 investigation. Using a literature search methodology comprising searches of PubMed (unlimited time-frame) and international hematology/oncology conference abstracts (2019-2023), this paper reviews the importance of Ikaros and Aiolos in MM, the mechanism of action of the IMiDs and CELMoD agents and their relative potency for targeting Ikaros and Aiolos, and preclinical and clinical data on iberdomide and mezigdomide. EXPERT OPINION: Emerging data suggest that iberdomide and mezigdomide have promising activity, including in IMiD-resistant settings and, pending phase 3 findings, may provide additional treatment options for patients with MM.

Mezigdomide-A Novel Cereblon E3 Ligase Modulator under Investigation in Relapsed/Refractory Multiple Myeloma.

Mezigomide is an oral cereblon E3 ligase modulator (CELMoD) that is under clinical investigation in patients with relapsed/refractory (RR) multiple myeloma (MM). Like other CELMoD compounds, mezigdomide acts by altering the conformation of cereblon within the cullin 4A ring ligase-cereblon (CRL4CRBN) E3 ubiquitin ligase complex, thereby recruiting novel protein substrates for selective proteasomal degradation. These include two critical lymphoid transcription factors, Ikaros family zinc finger proteins 1 and 3 (IKZF1 and IKZF3), also known as Ikaros and Aiolos, which have important roles in the development and differentiation of hematopoietic cells, in MM pathobiology, and in suppressing the expression of interferon-stimulating genes and T-cell stimulation. Among the CELMoDs, mezigdomide has the greatest cereblon-binding potency, plus the greatest potency for the degradation of Ikaros and Aiolos and subsequent downstream antimyeloma effects. Preclinical studies of mezigdomide have demonstrated its anti-proliferative and apoptotic effects in MM, along with its immune-stimulatory effects and its synergistic activity with other antimyeloma agents, including in lenalidomide-/pomalidomide-resistant MM cell lines and mouse xenograft models. Early-phase clinical trial data indicate notable activity in heavily pretreated patients with RRMM, including those with triple-class-refractory disease, together with a tolerable and manageable safety profile. This review summarizes current preclinical and clinical findings with mezigdomide and its potential future roles in the treatment of MM.

Upfront or Deferred Autologous Stem Cell Transplantation for Newly Diagnosed Multiple Myeloma in the Era of Triplet and Quadruplet Induction and Minimal Residual Disease/Risk-Adapted Therapy.

The standards of care for the initial treatment of patients with newly diagnosed multiple myeloma (NDMM) who are eligible for high-dose melphalan and autologous stem cell transplantation (HDM-ASCT) include highly active triplet and quadruplet regimens based on proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies. These regimens are resulting in improved outcomes and increasingly high rates of minimal residual disease (MRD)-negative responses without HDM-ASCT as part of the upfront therapy. Furthermore, recent randomized studies have shown that, while transplant-based approaches as a frontline therapy result in significantly longer progression-free survival compared to non-transplant approaches, this has not translated into an overall survival benefit. Given these developments, and in the context of the treatment burden of undergoing HDM-ASCT, in addition to the acute toxicities and long-term sequelae of HDM, which are associated with the genotoxicity of melphalan, there is an increasing rationale for considering deferring upfront HDM-ASCT in select transplant-eligible patients and saving it as a treatment option for later salvage therapy. Here, we review the latest clinical trial data on upfront or deferred HDM-ASCT and on the activity of quadruplet induction regimens, including rates of MRD-negative responses, and summarize emerging treatment approaches in the upfront setting such as the use of MRD-directed therapy and alternatives to HDM-ASCT.

Real-world multiple myeloma risk factors and outcomes by non-Hispanic Black/African American and non-Hispanic White race/ethnicity in the United States.

Examination of the impact of race and ethnicity on multiple myeloma (MM) outcomes has yielded inconsistent results. This retrospective, real-world (RW) study describes patient, disease, and treatment characteristics (and associations with survival outcomes) among newly diagnosed MM patients of non-Hispanic (NH) Black/African American (AA) and NH White race/ethnicity in the United States. We included patients from the nationwide Flatiron Health electronic health record-derived de-identified database who initiated first line of therapy (LOT) for MM between January 1, 2016 and March 31, 2022. Of 4,614 patients in our study cohort, 23.3% were NH Black/AA. Non-Hispanic Black/AA patients were younger than NH White patients at diagnosis (median 68 vs 71 years) and more likely to be female (53.4% vs 43.5%). Rates of high-risk cytogenetics and 1q21+ were similar between races/ethnicities. The most common primary regimen used was lenalidomide-bortezomib-dexamethasone (50.1% of NH Black/AA and 48.1% of NH White patients). Receipt of stem cell transplantation during first LOT was less common among NH Black/AA (16.5%) than NH White (21.9%) patients. Unadjusted RW progression-free survival (rwPFS) and overall survival (rwOS) were similar between races/ethnicities. After multivariable adjustment, NH Black/AA race/ethnicity was associated with slightly inferior rwPFS (hazard ratio [HR] 1.13; 95% CI 1.01-1.27). The difference in rwOS (HR 1.12; 95% CI 0.98-1.28) was not statistically significant. In general, associations between risk factors for rwPFS and rwOS were consistent between races/ethnicities. Findings from this analysis help to inform clinicians about the impact of race/ethnicity on MM treatment paradigms and outcomes in the United States.

A safety review of recently approved and emerging drugs for patients with relapsed or refractory multiple myeloma.

INTRODUCTION: Multiple new drugs have been approved over the past 5 years for the treatment of relapsed/refractory multiple myeloma (RRMM), and these are being increasingly widely used. Clinicians need to familiarize themselves with common toxicities associated with these drugs and with novel toxicities requiring specific management and supportive care. AREAS COVERED: We review common toxicities associated with agents approved for RRMM in the past 5 years, including the anti-CD38 monoclonal antibody isatuximab, the antibody-drug conjugate belantamab mafodotin, the bispecific antibody teclistamab, the chimeric antigen receptor (CAR) T cell products idecabtagene vicleucel and ciltacabtagene autoleucel, the selective inhibitor of nuclear export compound selinexor, and the drug-peptide conjugate melflufen, as well as toxicities associated with emerging agents for RRMM including additional bispecific antibodies, the BCL-2 inhibitor venetoclax, and the cereblon E3 ligase modulators iberdomide and mezigdomide. We searched the published literature using PubMed, plus congress abstracts, for the above list of drug names or classes and 'myeloma.' EXPERT OPINION: Optimal management of toxicities associated with these recently approved and emerging therapies will be critical in maximizing clinical benefit and aiding widespread adoption in routine clinical practice. We summarize current recommendations and guidelines and provide expert insights into supportive care requirements.

Selinexor: Targeting a novel pathway in multiple myeloma.

Selinexor is an orally bioavailable selective inhibitor of nuclear export compound that inhibits exportin-1 (XPO1), a novel therapeutic target that is overexpressed in multiple myeloma (MM) and is responsible for the transport of ∼220 nuclear proteins to the cytoplasm, including tumour suppressor proteins. Inhibition of this process has demonstrated substantial antimyeloma activity in preclinical studies, both alone and in combination with established MM therapeutics. Based on a clinical trial programme encompassing multiple combination regimens, selinexor-based therapy has been approved for the treatment of relapsed/refractory MM (RRMM), with selinexor-dexamethasone approved in the later-relapse setting for penta-refractory patients and selinexor-bortezomib-dexamethasone approved for patients who have received ≥1 prior therapy. Here, we provide a comprehensive review of the clinical data on selinexor-based regimens, including recent updates from the 2022 American Society of Hematology annual meeting, and summarise ongoing studies of this novel targeted agent in newly diagnosed MM and RRMM.

Kidney transplantation in patients with multiple myeloma: narrative analysis and review of the last two decades.

There have been significant advances in the treatment of multiple myeloma in the last two decades. Approximately 25% of patients with newly diagnosed myeloma have some degree of kidney impairment. During the course of illness, nearly 50% of myeloma patients will develop kidney disease. Moreover, ∼10% of myeloma patients have advanced kidney disease requiring dialysis at presentation. Hemodialysis is associated with a significantly reduced overall survival (OS). In the setting of prolonged long-term OS due to the use of newer immunotherapeutic agents in the treatment of myeloma, patients with myeloma and advanced kidney disease may benefit from more aggressive management with kidney transplantation (KTx). Unfortunately, most data regarding outcomes of KTx in patients with myeloma come from single-center case series. With the advent of novel treatment choices, it remains unclear if outcomes of kidney transplant recipients with myeloma have improved in recent years. In this descriptive systematic review, we coalesced published patient data over the last 20 years to help inform clinicians and patients on expected hematologic and KTx outcomes in this complex population. We further discuss the future of KTx in patients with paraproteinemia.

Quantification of peptides from immunoglobulin constant and variable regions by LC-MRM MS for assessment of multiple myeloma patients.

PURPOSE: Quantitative MS assays for Igs are compared with existing clinical methods in samples from patients with plasma cell dyscrasias, for example, multiple myeloma (MM). EXPERIMENTAL DESIGN: Using LC-MS/MS data, Ig constant region peptides, and transitions were selected for LC-MRM MS. Quantitative assays were used to assess Igs in serum from 83 patients. RNA sequencing and peptide-based LC-MRM are used to define peptides for quantification of the disease-specific Ig. RESULTS: LC-MRM assays quantify serum levels of Igs and their isoforms (IgG1-4, IgA1-2, IgM, IgD, and IgE, as well as kappa (κ) and lambda (λ) light chains). LC-MRM quantification has been applied to single samples from a patient cohort and a longitudinal study of an IgE patient undergoing treatment, to enable comparison with existing clinical methods. Proof-of-concept data for defining and monitoring variable region peptides are provided using the H929 MM cell line and two MM patients. CONCLUSIONS AND CLINICAL RELEVANCE: LC-MRM assays targeting constant region peptides determine the type and isoform of the involved Ig and quantify its expression; the LC-MRM approach has improved sensitivity compared with the current clinical method, but slightly higher inter-assay variability. Detection of variable region peptides is a promising way to improve Ig quantification, which could produce a dramatic increase in sensitivity over existing methods, and could further complement current clinical techniques.

State-of-the-Art Management of Complications of Myeloma and Its Treatment.

Multiple myeloma is an incurable disease, although patient survival has increased with the availability of novel agents. Both multiple myeloma and its therapies often affect the renal, immune, skeletal, hematologic, and nervous systems. The resulting organ dysfunctions often impair the quality of life of affected patients, complicate and limit subsequent therapies, and may result in significant mortality. Research on the treatment of complications of multiple myeloma has been limited; hence, preventative and management strategies for patients with these complications are heterogeneous and often based on anecdotal experience. In this paper, we review the effects of myeloma and the novel therapies on organ systems and suggest management strategies.