Management of Primary Plasma Cell Leukemia Remains Challenging Even in the Era of Novel Agents

Venetoclax in the treatment of secondary plasma cell leukemia with translocation t(11;14): a case report and literature review

Introduction

Venetoclax is a BCL-2 inhibitor with proven efficacy in patients with multiple myeloma (MM) and translocation t(11;14). However, its role in plasma cell leukemia (PCL) remains unclear. Herein, we aimed to report a case of relapsed MM with secondary PCL and t(11;14) achieving complete (CR) and durable remission with venetoclax therapy.

Case presentation

A 52-year-old gentleman was diagnosed with MM-free light chain lambda (ISS III) in December 2016. He received induction therapy, followed by autologous stem cell transplant. (ASCT) in May 2017 and maintenance. A year later, the patient relapsed with secondary PCL. His cytogenetics analysis revealed t(11; 14). The patient failed salvage chemotherapy and was shifted to venetoclax with dexamethasone treatment. The patient attained complete remission (CR), which was maintained for two years and a half before he developed fatal COVID-19 pneumonia.

Conclusion

In comparison with the reported literature, this case report offers the latest compilation of the available evidence on the use of venetoclax in patients with PCL. Furthermore, our patient achieved CR for the longest reported durable response in literature thus far. Prospective clinical trials are needed to elucidate the optimal dosage, combination, and duration of treatment, ensuring better representation and generalizability of the findings. Meanwhile, venetoclax may be considered as a therapeutic option in patients with PCL t(11;14).

A Clinical Perspective on Plasma Cell Leukemia: A Single-Center Experience

Circulating plasma cells (CPCs) are detected in most multiple myeloma (MM) patients, both at diagnosis and on relapse. A small subset, plasma cell leukemia (PCL), represents a different biology and has a poor prognosis. In this retrospective analysis, we evaluated patients with primary (pPCL, n = 35) or secondary (sPCL, n = 49), with ≥5% CPCs and a smaller subset with lower CPCs of 1-4% (n = 20). The median age was 61 years; 45% were men and 54% were Black. High-risk cytogenetics were found in 87% and extramedullary disease in 47%. For the entire cohort, 75% received a proteasome inhibitor, 70% chemotherapy, 54% an immunomodulatory drug, 24% a daratumumab-based regimen and 26% an autologous stem cell transplant (ASCT). The treatments marginally improved the overall survival (OS) for pPCL vs. sPCL (13 vs. 3.5 months p = 0.002). However, the 5-year survival for the whole cohort was dismal at 11%. High-risk cytogenetics, low platelets, extramedullary disease and high LDH were independently associated with poor outcomes. Further research is urgently needed to expand the treatment options and improve the outcomes in PCL.

Single-Center Experience of Patients with Plasma Cell Leukemia in the Era of New Therapeutics

INTRODUCTION

Plasma cell leukemia (PCL) can occur de novo as primary PCL (pPCL), or in patients with prior diagnosis of multiple myeloma (MM) as secondary PCL (sPCL). In 2021, the diagnostic criteria have been revised, establishing a new cut-off of ≥5% plasma cells in the peripheral blood. Lacking specific clinical trials, PCL is treated similarly to MM; however, outcome for patients with PCL remains poor. Here, we report outcomes for patients with pPCL and sPCL in the era of novel agents.

METHODS

We performed a retrospective analysis and identified 19 patients (11 pPCL, 8 sPCL) who have been treated for PCL between 2010 and 2022 at University Hospital Essen.

RESULTS

Patients with pPCL had a median overall survival (OS) of 37.8 months (95% CI: [15.4; 52.3] months) from diagnosis, with a median time to next treatment (TTNT) of 18.4 (2.0; 22.9) months. All patients were treated with a proteasome-inhibitor (PI)-based induction therapy, and the majority was consolidated with an autologous stem cell transplantation (SCT). Five of these patients received a tandem transplantation. Patients with sPCL had a median OS of only 1.5 months after diagnosis of PCL. Only 1 patient achieved a remission with daratumumab and subsequent allogenic SCT.

CONCLUSION

With our study, we add evidence for a PI-based induction therapy followed by a consolidating autologous SCT for patients with pPCL and give further evidence that a tandem transplant concept might be beneficial. The diagnosis of sPCL remains devastating and needs new therapeutic approaches.

Prognostic value of circulating plasma cells detected by flow cytometry in newly diagnosed multiple myeloma patients: a systematic review and meta-analysis

OBJECTIVES

Multiple myeloma (MM) is a malignant plasma cell disorder. The most widely accepted staging system for MM is the revised International Staging System based on cytogenetic and clinical biomarkers. The circulating clonal plasma cells (CPCs) were reported to have potential prognostic impact on MM. Among various diagnostic approaches, multiparametric flow cytometry (FCM) offers heightened sensitivity, minimal invasiveness and reproducibility. We conducted a meta-analysis to evaluate the prognostic value of quantifying CPCs via FCM in newly diagnosed symptomatic MM (NDMM) patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCE

PubMed, Web of Science, Embase and references of included studies.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

We included observational studies that evaluated the prognostic value of CPCs detected by FCM in NDMM.

DATA EXTRACTION AND SYNTHESIS

Data were screened and extracted independently by two investigators. The pooled results originated from random effects models. The primary endpoint was overall survival (OS). The secondary endpoint was progression-free survival (PFS). To evaluate the prognostic value of CPCs in NDMM, HRs and their 95% CI for both OS and PFS were derived using COX multivariable models. These values were then used to compute the pooled estimated effect.

RESULTS

Our meta-analysis encompassed a total of 2704 NDMM patients from 11 studies up to 27 August 2022. The pooled HR for OS and PFS in CPC-positive (CPCs+) group and CPC-negative group were 1.95 (95% CI 1.24 to 3.07) and 2.07 (95% CI 1.79 to 2.39), respectively. The autologous stem cell transplantation (ASCT) failed to eliminate the adverse impact on OS and PFS. The heterogeneity may stem from the use of novel agents or traditional chemotherapy as initial treatment.

CONCLUSION

This meta-analysis indicates CPCs+ had an adverse impact on the prognosis of NDMM patients in the total population, and the adverse impact could not be eliminated by ASCT.

PROSPERO REGISTRATION NUMBER

CRD42021272381.

Clinicopathological and laboratory parameters of plasma cell leukemia among Indian population

BACKGROUND

Plasma cell leukemia (PCL) is a rare and aggressive plasma cell neoplasm distinguished by extensive clonal expansion of plasma cells in the bone marrow (BM) and peripheral blood (PB). PCL is divided into two subtypes: primary (pPCL) originates de novo without preceding multiple myeloma, while secondary (sPCL) comprises a leukemic modification that occurs as a late manifestation from previous multiple myeloma (MM). pPCL and sPCL are clinically and biologically two different entities. The molecular mechanisms of the development of PCL, either primary or secondary, remain poorly understood. We aim to present 5 years of data on clinical profiles and treatment outcomes of pPCL and sPCL patients treated at our cancer hospital in India and to find a predictive parameter of the development of PCL in cases of MM.

METHODS

In this study, we retrospectively reviewed and evaluated the clinicopathological features, laboratory parameters, immunophenotypic profile, and patient outcomes of 17 PCL cases diagnosed among 180 plasma cell dyscrasia patients during the study period to establish a correlation between pPCL & sPCL for diagnosis and management of PCL.

RESULTS

A total of 17 PCL patients were diagnosed among 180 plasma cell dyscrasia patients during the study period. Among PCL patients, 9 cases had pPCL (52.94% of all PCL patients), and 8 cases had sPCL (47.06% of all PCL patients). Peculiar differences were seen between the two PCL types. Both types of PCL had a younger age at the time of diagnosis, having elevated BM plasma cell infiltration percentage, frequent anemia, thrombocytopenia, elevated beta-2-microglobulin (B2M) levels, raised LDH levels, and positive M-protein in both serum and urine. In addition, SFLC assay and Immunofixation assay showed higher κ and lower λ in pPCL compared with sPCL (P<0.05). Higher Renal insufficiency was also observed in pPCL compared to sPCL (P=0.335). The survival and response to treatment of PCL patients remain considerably poor, sPCL exhibit shorter overall survival (OS) than pPCL with (median 1.75 months vs. 7 months respectively, P=0.1682). Plasma cell leukemia (PCL) needs to be diagnosed early and requires prompt initiation of treatment before patients get complications.

CONCLUSION

Our study characterizes the clinical and laboratory features of pPCL and sPCL and may aid physicians in prognosticating the course of disease of their patients. However, future multicentre studies are the need of the hour to develop accurate diagnostic criteria and establish the efficacy of therapeutic regimens.

Genomics of Plasma Cell Leukemia

Simple Summary

Plasma cell leukemia (PCL) is a very aggressive plasma cell disorder with a dismal prognosis, despite the therapeutic progress made in the last few years. The implementation of genomic high-throughput technologies in the clinical setting has revealed new insights into the genomic landscape of PCL, some of which may have an impact on the development of novel therapeutic approaches. The purpose of this review is to provide a comprehensive overview and update of the genomic studies carried out in PCL.

Abstract

Plasma cell leukemia (PCL) is a rare and highly aggressive plasma cell dyscrasia characterized by the presence of clonal circulating plasma cells in peripheral blood. PCL accounts for approximately 2–4% of all multiple myeloma (MM) cases. PCL can be classified in primary PCL (pPCL) when it appears de novo and in secondary PCL (sPCL) when it arises from a pre-existing relapsed/refractory MM. Despite the improvement in treatment modalities, the prognosis remains very poor. There is growing evidence that pPCL is a different clinicopathological entity as compared to MM, although the mechanisms underlying its pathogenesis are not fully elucidated. The development of new high-throughput technologies, such as microarrays and new generation sequencing (NGS), has contributed to a better understanding of the peculiar biological and clinical features of this disease. Relevant information is now available on cytogenetic alterations, genetic variants, transcriptome, methylation patterns, and non-coding RNA profiles. Additionally, attempts have been made to integrate genomic alterations with gene expression data. However, given the low frequency of PCL, most of the genetic information comes from retrospective studies with a small number of patients, sometimes leading to inconsistent results.

LncRNAs LY86-AS1 and VIM-AS1 Distinguish Plasma Cell Leukemia Patients from Multiple Myeloma Patients

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides. Due to modern genomic techniques, the involvement of lncRNAs in tumorigenesis has been revealed; however, information concerning lncRNA interplay in multiple myeloma (MM) and plasma cell leukemia (PCL) is virtually absent. Herein, we aimed to identify the lncRNAs involved in MM to PCL progression. We investigated representative datasets of MM and PCL patients using next-generation sequencing. In total, 13 deregulated lncRNAs (p < 0.00025) were identified; four of them were chosen for further validation in an independent set of MM and PCL patients by RT-qPCR. The obtained results proved the significant downregulation of lymphocyte antigen antisense RNA 1 (LY86-AS1) and VIM antisense RNA 1 (VIM-AS1) in PCL compared to MM. Importantly, these two lncRNAs could be involved in the progression of MM into PCL; thus, they could serve as promising novel biomarkers of MM progression.