Clonal Evolution of Multiple Myeloma-Clinical and Diagnostic Implications

The choice of serum-free light chain analysis method could potentially have clinical consequences for myeloma patients

Multiple myeloma (MM) is a disease, that at times poses diagnostic and monitoring challenges. Over the last decades laboratory methods have been expanded with serum free light chain (FLC) analysis. Alerted by two index cases with clinical impact due to failure of the FLC analysis to indicate a disease progression, we aimed to identify any clinical consequences due to known differences between FLC analysis methods. We applied two FLC analysis methods (Freelite Binding Site [FBS] and N-Latex Siemens [NLS]) on all patients with MM and monoclonal gammopathy of uncertain significance diagnosed/followed up at Södra Älvsborg Hematology Unit, from April to December 2022. From a total of 123 patients with malignant plasma cell disorder, we identified five cases (4.1%) where solely the FBS method, as opposed to NLS, urine and serum electrophoresis, could support diagnosis or detect progression. The consequences of this discrepancy included not only change of diagnosis or delayed therapy but also change of treatment. Our findings indicate that a stronger awareness of the potential weaknesses of different FLC methods is needed, which calls for a closer collaboration between clinical chemists and hematologists.

A Phase I Trial Evaluating the Addition of Lenalidomide to Patients with Relapsed/Refractory Multiple Myeloma Progressing on Ruxolitinib and Methylprednisolone

BACKGROUND

Ruxolitinib (RUX), an orally administered selective Janus kinase 1/2 inhibitor, has received approval for the treatment of myelofibrosis, polycythemia vera, and graft-versus-host disease. We have previously demonstrated the anti-multiple myeloma effects of RUX alone and in combination with the immunomodulatory agent lenalidomide (LEN) and glucocorticosteroids both pre-clinically and clinically.

OBJECTIVE

This study aims to evaluate whether LEN can achieve clinical activity among patients with multiple myeloma progressing on the combination of RUX and methylprednisolone (MP).

METHODS

In this part of a phase I, multicenter, open-label study, we evaluated the safety and efficacy of RUX and MP for patients with multiple myeloma with progressive disease who had previously received a proteasome inhibitor, LEN, glucocorticosteroids, and at least three prior regimens; we also determined the safety and efficacy of adding LEN at the time of disease progression from the initial doublet treatment. Initially, all subjects received oral RUX 15 mg twice daily and oral MP 40 mg every other day. Those patients who developed progressive disease according to the International Myeloma Working Group criteria then received LEN 10 mg once daily on days 1-21 within a 28-day cycle in addition to RUX and MP, which were administered at the same doses these patients were receiving at the time progressive disease developed.

RESULTS

Twenty-nine subjects (median age 64 years; 18 [62%] male) were enrolled in this part of the study and initially received the two-drug combination of RUX and MP. The median number of prior therapies was six (range 3-12). The overall response rate from this two-drug combination was 31% and the clinical benefit rate was 34%. The best responses were 1 very good partial response, 8 partial responses, 1 minor response, 12 stable disease, and 7 progressive disease. The median progression-free survival was 3.5 months (range  0.5-36.2 months). The median time to response was 3.0 months. The median duration of response was 12.5 months (range 2.8-36.2 months). Twenty (69%) patients who showed progressive disease had LEN added to RUX and MP; all patients had prior exposure to LEN and all but one patient was refractory to their last LEN-containing regimen. After the addition of LEN, the overall response rate was 30% and the clinical benefit rate was 40%. The best responses of patients following the addition of LEN were 2 very good partial responses, 4 partial responses, 2 minor responses, 8 stable disease, and 4 progressive disease. The median time to response was 2.6 months (range 0.7-15.0 months). The median duration of response was not reached. The median progression-free survival following the addition of LEN was 3.5 months (range 0.3-25.9 months).

CONCLUSIONS

For patients with multiple myeloma, treatment with RUX and MP is effective and well tolerated, and LEN can be used to extend the benefit of this RUX-based treatment.

CLINICAL TRIAL REGISTRATION

This study is registered with ClinicalTrials.gov, NCT03110822, and is ongoing.

Efficacy and Safety of Anti-CD38 Monoclonal Antibodies in Patients with Relapsed or Refractory Multiple Myeloma: A Meta-Analysis of Randomized Clinical Trials

The benefit of associating anti-CD38 monoclonal antibodies to proteasome inhibitor (PI)/immunomodulatory agent (IA) and dexamethasone in the treatment of patients with relapsed or refractory multiple myeloma (MM) remains unclear. PubMed, Embase, and Cochrane Library databases were searched for randomized controlled trials that investigated the addition of anti-CD38 monoclonal antibodies to a therapy composed of PI/IA and dexamethasone versus PI/IA and dexamethasone alone for treating relapsed or refractory MM. Hazard ratios (HRs) or risk ratios (RRs) were computed for binary endpoints, with 95% confidence intervals (CIs). Six studies comprising 2191 patients were included. Anti-CD38 monoclonal antibody significantly improved progression-free survival (HR 0.52; 95% CI 0.43-0.61; p < 0.001) and overall survival (HR 0.72; 95% CI 0.63-0.83; p < 0.001). There was a significant increase in hematological adverse events, such as neutropenia (RR 1.41; 95% CI 1.26-1.58; p < 0.01) and thrombocytopenia (RR 1.14; 95% CI 1.02-1.27; p = 0.02), in the group treated with anti-CD38 monoclonal antibody. Also, there was a significant increase in non-hematological adverse events, such as dyspnea (RR 1.72; 95% CI 1.38-2.13; p < 0.01) and pneumonia (RR 1.34; 95% CI 1.13-1.59; p < 0.01), in the group treated with anti-CD38 monoclonal antibody. In conclusion, the incorporation of an anti-CD38 monoclonal antibody demonstrated a promising prospect for reshaping the established MM treatment paradigms.

From Multiple Myeloma to Acute Myeloid Leukemia: A Case Report of a 61-year-old Woman after 8 Years of Chemotherapy and Immunotherapy

BACKGROUND

As the second most prevalent hematologic malignancy, multiple myeloma (MM) affects plasma cells and is characterized by chromosomal abnormalities, particularly involving the immunoglobulin heavy chain switch region. MM represents a biologically and clinically heterogeneous hematological malignancy that serves as a clonal evolution model, exhibiting clonal heterogeneity throughout all stages from monoclonal gammopathy undetermined significance (MGUS) and smoldering multiple myeloma (SMM) to MM. Although significant progress has been made in the treatment of MM, leading to improved patient outcomes, concerns are arising regarding disease relapse due to the presence and selection of pre-existing resistant clones or selective pressure during therapy.

CASE PRESENTATION

We present a case of multiple myeloma (MM) in a female patient, who underwent an 8-year course of treatment, including chemotherapy, immunomodulators, hematopoietic stem cell transplantation, CD38 monoclonal antibody, and chimeric antigen receptor T-cell (CAR-T), and was recently diagnosed with concurrent progressive MM and acute myeloid leukemia (AML). This patient has witnessed the evolution of MM treatment paradigms.

CONCLUSION

In this course, disease relapses occurred twice, one of which was manifested by a light chain escape (LCE). Moreover, through the course of the disease in this patient, we review the process of clonal evolution that may be relevant.

Isolated Non-Secretory Extramedullary Relapse of Multiple Myeloma Responded Completely to Localized Radiotherapy

Introduction

Non-secretory multiple myeloma (NSMM) is a rare form of multiple myeloma (MM) that is often difficult to detect and has not yet been well characterized. This is due to the lack of production or the presence of monoclonal protein (MP) levels below levels detectable by testing such as serum/urine electrophoresis and immunofixation.

Case Presentation

Two patients of ours were being treated for MM with typical courses of systemic therapy. By the third-line therapy, both developed an extramedullary mass, one in the pelvis and the other in the neck. In both cases, blood work showed no measurable MP, normal free light chain levels, and unremarkable skeletal surveys. Secondary malignancies were suspected due to the clinical presentation in each case, and biopsies confirmed the presence of non-secretory plasmacytomas. Both patients were only treated with localized radiotherapy with a total dose of 2,000 cGy in 5 fractions over 1 week. Ultimately, this resolved the original masses with no residual tumors. No changes had to be made to their systemic therapies, and both patients remained stable.

Conclusion

NSMM relapse is not unusual and should be suspected in patients with relapsed refractory disease. Relapse should be confirmed by a tissue biopsy, and secondary malignancies should be ruled out. Radiotherapy is an excellent option to treat localized relapse and preserve the current line of systemic anti-myeloma therapy.

Identification of evolutionary mechanisms of myelomatous effusion by single-cell RNA sequencing

Myelomatous effusion (ME) is a rare manifestation of extramedullary multiple myeloma (MM) with limited therapeutic options and poor outcomes. The molecular mechanisms underlying ME are incompletely understood. We profiled transcriptomes of bone marrow, peripheral blood (PB), and pleural effusion/ascites from 3 patients with ME using single-cell RNA sequencing analysis. We found that ME contained a higher percentage of cytotoxic T cells, whereas PB contained a higher proportion of naive T cells. Malignant cells varied within and between sites and patients in their expression of signatures. We identified a gene module highly expressed in intramedullary and extramedullary plasma cell clusters and defined cell clusters expressing this gene set as extramedullary-initiating cells (EMICs). This gene set was associated with increased cellular proliferation, involved in p53 signaling, and related to poor prognosis in MM. The transcriptional regulators E2F1, YY1, and SMAD1 were activated in EMICs. Leukocyte immunoglobulin-like receptor subfamily B4 (LILRB4) was upregulated in extramedullary EMICs. We confirmed that LILRB4 promoted MM cell migration in vitro. This study provided insight into the evolutionary mechanisms of ME and defined EMICs and LILRB4 associated with extramedullary development.

Tracking Clonal Evolution of Multiple Myeloma Using Targeted Next-Generation DNA Sequencing

Clonal evolution drives treatment failure in multiple myeloma (MM). Here, we used a custom 372-gene panel to track genetic changes occurring during MM progression at different stages of the disease. A tumor-only targeted next-generation DNA sequencing was performed on 69 samples sequentially collected from 30 MM patients. The MAPK/ERK pathway was mostly affected with KRAS mutated in 47% of patients. Acquisition and loss of mutations were observed in 63% and 37% of patients, respectively. Four different patterns of mutation evolution were found: branching-, mutation acquisition-, mutation loss- and a stable mutational pathway. Better response to anti-myeloma therapy was more frequently observed in patients who followed the mutation loss-compared to the mutation acquisition pathway. More than two-thirds of patients had druggable genes mutated (including cases of heavily pre-treated disease). Only 7% of patients had a stable copy number variants profile. Consequently, a redistribution in stages according to R-ISS between the first and paired samples (R-ISS″) was seen. The higher the R-ISS″, the higher the risk of MM progression and death. We provided new insights into the genetics of MM evolution, especially in heavily pre-treated patients. Additionally, we confirmed that redefining R-ISS at MM relapse is of high clinical value.