High-risk smoldering myeloma versus early detection of multiple myeloma: Current models, goals of therapy, and clinical implications

Exploring the molecular biomarker utility of circCCT3 in multiple myeloma: A favorable prognostic indicator, particularly for R-ISS II patients

Circular RNAs (circRNAs) are associated with the pathobiology of multiple myeloma (MM). Recent findings regarding circCCT3 support its involvement in the development and progression of MM, through microRNA sponging. Thus, we aimed to examine the expression of circCCT3 in smoldering and symptomatic MM and to assess its clinical importance. Three cell lines from plasma cell neoplasms were cultured and bone marrow aspirate (BMA) samples were collected from 145 patients with MM or smoldering MM. Next, CD138+ enrichment was performed in BMA samples, followed by total RNA extraction and reverse transcription. Preamplification of circCCT3 and GAPDH cDNA was performed. Finally, a sensitive assay for the relative quantification of circCCT3 using nested real-time quantitative polymerase chain reaction was developed, optimized, and implemented in the patients' samples and cell lines. MM patients exhibited significantly higher intracellular circCCT3 expression in their CD138+ plasma cells, compared to those from SMM patients. In addition, MM patients overexpressing circCCT3 had longer progression-free and overall survival intervals. The favorable prognostic significance of high circCCT3 expression in MM was independent of disease stage (either International Staging System [ISS] or revised ISS [R-ISS]) and age of MM patients. Interestingly, circCCT3 expression could serve as a surrogate molecular biomarker of prognosis in MM patients, especially those of R-ISS stage II. In conclusion, our study sheds new light on the significance of circCCT3 as a promising molecular marker for predicting MM patients' prognosis.

Single cell clonotypic and transcriptional evolution of multiple myeloma precursor disease

Multiple myeloma remains an incurable disease, and the cellular and molecular evolution from precursor conditions, including monoclonal gammopathy of undetermined significance and smoldering multiple myeloma, is incompletely understood. Here, we combine single-cell RNA and B cell receptor sequencing from fifty-two patients with myeloma precursors in comparison with myeloma and normal donors. Our comprehensive analysis reveals early genomic drivers of malignant transformation, distinct transcriptional features, and divergent clonal expansion in hyperdiploid versus non-hyperdiploid samples. Additionally, we observe intra-patient heterogeneity with potential therapeutic implications and identify distinct patterns of evolution from myeloma precursor disease to myeloma. We also demonstrate distinctive characteristics of the microenvironment associated with specific genomic changes in myeloma cells. These findings add to our knowledge about myeloma precursor disease progression, providing valuable insights into patient risk stratification, biomarker discovery, and possible clinical applications.

The role of soluble B cell maturation antigen as a biomarker in multiple myeloma

Currently used stratification models in myeloma precursor disease as well as staging systems and response criteria in myeloma have limitations including failure to identify functionally high-risk myeloma patients. B-cell maturation antigen, a transmembrane glycoprotein required for long-lived plasma cells, is specific and expressed by myeloma cells. When it sheds from the surface of myeloma cells it can be measured in the blood as serum (sBCMA) and correlated with clinical outcomes in myeloma precursor disease as well as in active myeloma. We performed a literature review using PubMed and found 825 articles since 1992 of which any articles related to sBCMA were reviewed. These studies show the potential of sBCMA to become an important biomarker in myeloma. Here, we describe the potential advantages of sBCMA in the biology, diagnosis, prognosis, and surveillance of myeloma, while also reviewing the challenges that lie ahead before it can be implemented as a clinical tool.

The Role of Allogeneic Stem Cell Transplantation in Multiple Myeloma: A Systematic Review of the Literature

Multiple myeloma (MM) is an indolent B-cell malignancy, where treatment is aimed at preventing organ dysfunction from light chain accumulation (slowing disease progression) and inducing remission. Allogeneic stem cell transplant (allo-SCT), through graft versus myeloma (GVM) effects, has the potential to induce remission to a potentially curative-like state. In this systematic review, we aimed to understand this relationship to the risks and severity of disease in categorized patients and gain an updated comprehension of the future of allo-SCT in MM treatment. We conducted this review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched the PubMed database to obtain the specified literature with both the use of keywords and Medical Subject Headings (MeSH). A total of 16 relevant articles were included for discussion after the quality appraisal was completed, as appropriate, by either the Cochrane tool or Newcastle-Ottawa checklist. Our review concludes that while allo-SCT may benefit high-risk patients, successful procedures may incorporate a tandem autologous hematopoietic stem cell transplant approach in combination with novel pharmacologic contributions for which there is an observed synergy in the modulation of the immunologic microenvironment. Furthermore, tailored patient selection by evaluating pre-transplant factors including high-risk cytogenetics, age, and pre-salvage International Staging System (ISS) can predict post-transplantation success including non-relapse mortality. Successive research should continue to revise and update treatment options as the evolving therapeutic drug regimens may change over the course of indolent disease.

What Is New in the Treatment of Smoldering Multiple Myeloma?

Smoldering multiple myeloma (SMM), an asymptomatic plasma cell neoplasm, is currently diagnosed according to the updated IMWG criteria, which reflect an intermediate tumor mass between monoclonal gammopathy of undetermined significance (MGUS) and active MM. However, SMM is a heterogeneous entity and individual case may go from an "MGUS-like" behavior to "early MM" with rapid transformation into symptomatic disease. This wide range of clinical outcomes poses challenges for prognostication and management of individual patients. However, initial studies showed a benefit in terms of progression or even survival for early treatment of high-risk SMM patients. While outside of clinical trials the conventional approach to SMM generally remains that of close observation, these studies raised the question of whether early treatment should be offered in high-risk patients, prompting evaluation of several different therapeutic approaches with different goals. While delay of progression to MM with a non-toxic treatment is clearly achievable by early treatment, a convincing survival benefit still needs to be proven by independent studies. Furthermore, if SMM is to be considered less biologically complex than MM, early treatment may offer the chance of cure that is currently not within reach of any active MM treatment. In this paper, we present updated results of completed or ongoing clinical trials in SMM treatment, highlighting areas of uncertainty and critical issues that will need to be addressed in the near future before the "watch and wait" paradigm in SMM is abandoned in favor of early treatment.

Marrow uptake on FDG PET/CT is associated with progression from smoldering to symptomatic multiple myeloma

OBJECTIVE

To determine association of body composition measurements on CT and PET with progression of smoldering myeloma to multiple myeloma.

METHODS

A retrospective cohort study in 65 patients with smoldering myeloma and PET/CT at diagnosis was performed at a tertiary cancer center. Subjects were between 38 and 87 years of age (mean 64) and included 37 males. Primary outcome was progression-free survival as a function of bone, fat, and muscle metrics on CT and PET (measured at the level of L4 pedicles) and clinical confounders. CT metrics included attenuation of L4 and retroperitoneal fat and various indices derived from the psoas muscle. PET measures included SUV_max and SUV_mean of L4, retroperitoneal fat, and psoas. Cox proportional hazards modeling was performed with entry and retention criteria of p < 0.1 and p < 0.05, respectively.

RESULTS

SUV_max and SUV_mean were associated for each compartment (R² = 0.78-0.84), and SUV_mean (SUV) was used for subsequent analyses. SUV of the L4 vertebral body was associated with attenuation of the L4 vertebral body (p = 0.0032). There was no association between SUV and CT for muscle and fat compartments. In the subset of patients with bone marrow biopsy results (n = 43), there was no association between SUV of L4 and plasma cell concentration on core biopsy or flow cytometry (p = 0.089 and 0.072, respectively). The final Cox model showed association with albumin (HR 0.29, 95%CI 0.088-0.93, p = 0.038), M protein (HR 1.31, 95%CI 1.021-1.68, p = 0.034), and SUV of L4 (HR 1.99, 95%CI 1.037-3.82, p = 0.039).

CONCLUSION

SUV of L4 is a prognostic indicator in patients with smoldering myeloma.

How we manage smoldering multiple myeloma

Smoldering myeloma (SMM) is an asymptomatic stage characterized by bone marrow plasma cells infiltration between 10-60% in absence of myeloma-defining events and organ damage. Until the revision of criteria of MM to require treatment, two main prognostic models, not overlapping each other, were proposed and used differently in Europe and in US. Novel manageable drugs, like lenalidomide and monoclonal antibodies, with high efficacy and limited toxicity, improvement in imaging and prognostication, challenge physicians to offer early treatment to highrisk SMM. Taking advantage from the debates offered by SOHO Italy, in this review we will update the evidence and consequent clinical practices in US and Europe to offer readers a uniform view of clinical approach at diagnosis, follow-up and supportive care in the SMM setting.