A clinical perspective on plasma cell leukemia; current status and future directions

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.

Human IL-6 fosters long-term engraftment of patient-derived disease-driving myeloma cells in immunodeficient mice

Multiple myeloma is a largely incurable and life-threatening malignancy of antibody-secreting plasma cells. An effective and widely available animal model that recapitulates human myeloma and related plasma cell disorders is lacking. We show that busulfan-conditioned human IL-6-transgenic (hIL-6-transgenic) NSG (NSG+hIL6) mice reliably support the engraftment of malignant and premalignant human plasma cells, including from patients diagnosed with monoclonal gammopathy of undetermined significance, pre- and postrelapse myeloma, plasma cell leukemia, and amyloid light chain amyloidosis. Consistent with human disease, NSG+hIL6 mice engrafted with patient-derived myeloma cells developed serum M spikes, and a majority developed anemia, hypercalcemia, and/or bone lesions. Single-cell RNA sequencing showed nonmalignant and malignant cell engraftment, the latter expressing a wide array of mRNAs associated with myeloma cell survival and proliferation. Myeloma-engrafted mice given CAR T cells targeting plasma cells or bortezomib experienced reduced tumor burden. Our results establish NSG+hIL6 mice as an effective patient-derived xenograft model for study and preclinical drug development of multiple myeloma and related plasma cell disorders.

Impact of Clonal Heterogeneity in Multiple Myeloma

Multiple myeloma is characterized by a highly heterogeneous disease distribution within the bone marrow-containing skeletal system. In this review, we introduce the molecular mechanisms underlying clonal heterogeneity and the spatio-temporal evolution of myeloma. We discuss the clinical impact of clonal heterogeneity, which is thought to be one of the biggest obstacles to overcome therapy resistance and to achieve cure.

Identification and assessment of new PIM2 inhibitors for treating hematologic cancers: A combined approach of energy-based virtual screening and machine learning evaluation

PIM2, part of the PIM kinase family along with PIM1 and PIM3, is often overexpressed in hematologic cancers, fueling tumor growth. Despite its significance, there are no approved drugs targeting it. In response to this challenge, we devised a thorough virtual screening workflow for discovering novel PIM2 inhibitors. Our process includes molecular docking and diverse scoring methods like molecular mechanics generalized born surface area, XGBOOST, and DeepDock to rank potential inhibitors by binding affinities and interaction potential. Ten compounds were selected and subjected to an adequate evaluation of their biological activity. Compound 2 emerged as the most potent inhibitor with an IC50 of approximately 135.7 nM. It also displayed significant activity against various hematological cancers, including acute myeloid leukemia, mantle cell lymphoma, and anaplastic large cell lymphoma (ALCL). Molecular dynamics simulations elucidated the binding mode of compound 2 with PIM2, offering insights for drug development. These results highlight the reliability and efficacy of our virtual screening workflow, promising new drugs for hematologic cancers, notably ALCL.

Making decisions for follow-up chemotherapy based on digital patient reported outcomes data in patients with multiple myeloma and other M protein diseases - A mixed method study

OBJECTIVES

To test if Patient Reported Outcomes (PRO) data can replace physical on-site consultation in determining if patients with multiple myeloma, AL amyloidosis, or plasma cell leukemia are ready for their next bortezomib treatment without dose reduction.

METHODS

We developed an online questionnaire addressing common side effects to bortezomib and an algorithm stratifying patients according to their responses and asked them to complete the questionnaire the day before attending the clinic. Applying a mixed-method study design of PRO data, time registrations, and interviews with patients and healthcare professionals, we tested the usability of electronic PRO data forming the basis of decision-making on whether patients are physically fit for the next treatment with an unchanged dose.

RESULTS

The questionnaire and the associated algorithm were able to identify patients who were physically fit for treatment without need for further consultation, with a positive predictive value of 98 %. The method proved to be feasible for all groups of patients regardless of age and educational level. Patients and healthcare professionals found the online questionnaire to be advantageous and flexible.

CONCLUSION

The use of PRO data to evaluate patients prior to bortezomib treatment is safe and feasible. Patients prefer to report their side effects themselves as it provides them with more freedom during their treatment.

Human IL-6 fosters long-term engraftment of patient derived disease-driving myeloma cells in immunodeficient mice

Multiple myeloma is a largely incurable and life-threatening malignancy of antibody-secreting plasma cells. An effective and widely available animal model that recapitulates human myeloma and related plasma cell disorders is lacking. We show that busulfan-conditioned hIL-6 transgenic NSG mice (NSG+hIL6) reliably support the engraftment of malignant and pre-malignant human plasma cells including from patients diagnosed with monoclonal gammopathy of undetermined significance, pre- and post-relapse myeloma, plasma cell leukemia, and AL amyloidosis. Consistent with human disease, NSG+hIL6 mice engrafted with patient-derived myeloma cells, developed serum M spikes, and a majority developed anemia, hypercalcemia, and/or bone lesions. Single cell RNA sequencing showed non-malignant and malignant cell engraftment, the latter expressing a wide array of mRNAs associated with myeloma cell survival and proliferation. Myeloma engrafted mice given CAR T-cells targeting plasma cells or bortezomib experienced reduced tumor burden. Our results establish NSG+hIL6 mice as an effective patient derived xenograft model for study and preclinical drug development of multiple myeloma and related plasma cell disorders.

Plasma cell leukemia with soft tissue involvement; reporting a rare case

Plasma cell leukemia (PCL) is a rare aggressive variant of multiple myeloma. PCL is diagnosed when clonal plasma cells constitute more than 20 % of the total circulating leukocytes or when the absolute plasma cell count exceeds 2 × 109 /L. Extramedullary involvement including cavity effusion is frequently seen at the time of diagnosis. However, soft tissue involvement is rarely encountered with only one published case in the English literature. We report a 74-year-old man, who presented with progressive shortness of breath over a few months. Laboratory studies showed leukocytosis (32 × 109 /L) with 26 % peripheral plasmacytoid cells and significantly elevated lactate dehydrogenase (> 2500 U/L). Serum protein electrophoresis detected a monoclonal IgG lambda band. A 7.4 cm left hilar mass, bilateral pleural effusion, and multiple fluorodeoxyglucose (FDG)-avid subcutaneous nodules in the pelvic and gluteal regions were demonstrated on imaging. Gluteal nodule biopsy revealed diffuse infiltrative CD138+ and MUM1+ cells with aberrant CD4, CD30, and BCL2 expression. The Ki-67 proliferation index was 70 %. Bone marrow biopsy showed sheets of atypical plasma cells with lambda-restriction and CD138 and MUM1 expression without cyclin D1 and CD20 expression. These cells comprise approximately 70-80 % of the bone marrow cellularity. A similar immunophenotype was demonstrated in peripheral and bone marrow flow cytometry. Molecular and cytogenetics showed an abnormal clone with a complex karyotype including monosomy 13 and 14q deletion. Overall, these findings are consistent with a plasma cell neoplasm. Our case study illustrates soft tissue involvement in PCL, which is rarely seen.

Uncommon Haematological Transformation: Chronic Myeloid Leukaemia Transitioning Into Plasma Cell Leukaemia in a Single Patient

A 40-year-old male patient who was a known case of chronic myeloid leukaemia (CML) was diagnosed two years back on tab imatinib 400 mg/day; he came with complaints of easy fatigability, syncopal attacks, and bone pain associated with low-grade fever for 15 days. Repeat haematological profile and a peripheral smear of the patient suggested features of plasma cell leukaemia (PCL)/plasma cell dyscrasia (PCD). A definitive treatment protocol of lenalidomide, bortezomib, and dexamethasone for PCL was prescribed to the patient. This medical case study emphasizes the rare possibility of the transformation of CML into PCL and the possible trigger of tyrosine kinase inhibitor for the same.

Survival trends and prognostic factors of patients with newly diagnosed multiple myeloma accompanied with extramedullary disease

Background: Extramedullary disease (EMD) is an unusual event in patients with MM. This study aimed to assess the prognostic impact of EMD and develop an EMD-based risk model to estimate the survival of patients with newly diagnosed multiple myeloma (NDMM).Methods: A total of 518 patients were enrolled in this study, of which 121 presented with EMD at the initial diagnosis. Patients were divided into non-EMD, extramedullary-bone-related (EM-B) and extramedullary-extraosseous (EM-E) groups. Clinical characteristics were compared using the chi-squared test or Fisher's exact test. Survival curves were plotted using the Kaplan-Meier method, and a nomogram was constructed based on the Cox proportional hazards model.Results: Compared to patients without EMDs, patients with EM-E were younger (p = 0.028), and those with EM-B had less renal damage (p < 0.001). The EM-E group had the worst progression-free survival (PFS) and overall survival (OS). In addition, patients with multiple sites of EMD invasion or high Ki67 expression had poor OS. Lenalidomide-based treatment showed the worst outcome, and autologous stem cell transplantation (ASCT) remarkably improved the survival of patients with EMD. A prognostic model (MM prognostic index, MM-PI) comprising lactate dehydrogenase (LDH), circulating plasma cells (CPC), del(17p), and type of extramedullary involvement was developed, and a 4-factor nomogram.Conclusions: We established a risk model incorporating extramedullary disease that provides accurate and individualized survival estimates for patients with NDMM.

BCLXL PROTAC degrader DT2216 targets secondary plasma cell leukemia addicted to BCLXL for survival

Secondary plasma cell leukemia (sPCL) is a rare form of aggressive plasma cell malignancy arising mostly at end-stage refractory multiple myeloma and consequently presenting limited therapeutic options. We analyzed 13 sPCL for their sensitivity to BH3 mimetics targeting either BCL2 (venetoclax) or BCLXL (A1155463) and showed that 3 sPCL were efficiently killed by venetoclax and 3 sPCL by A1155463. Accordingly, BH3 profiling of 2 sPCL sensitive to BCLXL inhibition confirmed their high BCLXL primed profile. While targeting BCLXL using BH3 mimetics induces platelets on-target drug toxicity, the recent development of DT2216, a clinical-stage BCLXL proteolysis targeting chimera PROTAC compound, provides an alternative strategy to target BCLXL. Indeed, DT2216 specifically degrades BCLXL via VHL E3 ligase, without inducing thrombocytopenia. We demonstrated in human myeloma cell lines and sPCL that sensitivity to DT2216 strongly correlated with the sensitivity to A1155463. Interestingly, we showed that low doses of DT2216 (nM range) were sufficient to specifically degrade BCLXL after 48 hours of treatment, consistent with VHL expression, in all cell lines but irrespectively to DT2216 sensitivity. In myeloma cells, DT2216 induced apoptotic cell death and triggered BAX and BAK activation. In conclusion, our study demonstrated that patients with sPCL addicted to BCLXL, a small but a very challenging group, could potentially receive therapeutic benefit from DT2216. Clinical trials of DT2216 in this subset of sPCL patients are warranted.

Recent advances in access to overcome cancer drug resistance by nanocarrier drug delivery system

Cancer is currently one of the most intractable diseases causing human death. Although the prognosis of tumor patients has been improved to a certain extent through various modern treatment methods, multidrug resistance (MDR) of tumor cells is still a major problem leading to clinical treatment failure. Chemotherapy resistance refers to the resistance of tumor cells and/or tissues to a drug, usually inherent or developed during treatment. Therefore, an urgent need to research the ideal drug delivery system to overcome the shortcoming of traditional chemotherapy. The rapid development of nanotechnology has brought us new enlightenments to solve this problem. The novel nanocarrier provides a considerably effective treatment to overcome the limitations of chemotherapy or other drugs resulting from systemic side effects such as resistance, high toxicity, lack of targeting, and off-target. Herein, we introduce several tumor MDR mechanisms and discuss novel nanoparticle technology applied to surmount cancer drug resistance. Nanomaterials contain liposomes, polymer conjugates, micelles, dendrimers, carbon-based, metal nanoparticles, and nucleotides which can be used to deliver chemotherapeutic drugs, photosensitizers, and small interfering RNA (siRNA). This review aims to elucidate the advantages of nanomedicine in overcoming cancer drug resistance and discuss the latest developments.

Plasma Cell Leukemia with Successful Upfront Venetoclax in Combination with Allogeneic Transplantation

BACKGROUND Plasma cell leukemia (PCL) is an aggressive form of plasma cell neoplasm. We report the first case of primary PCL successfully treated with upfront novel agents consisting of Venetoclax and daratumumab in combination with intensive chemotherapy and allogeneic transplantation. CASE REPORT A 59-year-old woman presented with epistaxis, gum bleeding, and blurred vision. On examination, she appeared pale, with multiple petechiae and hepatomegaly. Fundoscopy revealed retinal hemorrhages. Laboratory investigations revealed bicytopenia and leukocytosis, with mild coagulopathy and hypofibrinogenemia. Elevated globulin and calcium levels were also observed. Serum protein electrophoresis demonstrated IgG lambda paraproteinemia, with a serum-free light chain kappa-to-lambda ratio of 0.074. A skeletal survey revealed the presence of lytic lesions. Bone marrow investigations confirmed the presence of lambda-light-chain-restricted clonal plasma cells. FISH detected t(11;14) and 17p13.1 deletion. Therefore, a final diagnosis of primary PCL was made. The patient received 1 cycle of bortezomib, cyclophosphamide, and dexamethasone (VCD) and 5 cycles of Venetoclax-VCD, followed by an unsuccessful stem cell mobilization. One cycle of daratumumab in combination with bortezomib, lenalidomide, and dexamethasone (VRD) was then given. The patient achieved complete remission. She underwent allogeneic stem cell transplantation of an HLA-matched sibling donor. Post-transplant marrow assessment showed disease remission and absence of t(11;14) and 17p deletions. She was administered pamidronate and lenalidomide maintenance. She remained clinically well with a good performance status and no active graft-versus-host disease 18 months after transplant. CONCLUSIONS The success of our patient in achieving complete remission has highlighted the efficacy and safety of this novel therapy in the front-line management of PCL.

Isolated relapse of plasma cell leukemia in the central nervous systems: a case report and literature review

Plasma cell leukemia is a rare yet aggressive form of multiple myeloma characterized by high levels of plasma cells circulating in the peripheral blood. We recently experienced a case of plasma cell leukemia that had been in stringent complete remission for nine years after autologous stem cell transplantations with subsequent courses of lenalidomide maintenance therapy, and then relapsed as an extramedullary plasmacytoma in the central nervous system. Assessment of the bone marrow did not prove proliferation of plasma cells at relapse, but imbalanced elevation of serum levels of free light chains was observed without changes in other clinical biomarkers including immunoglobulin levels. Salvage chemotherapy with isatuximab, pomalidomide, and dexamethasone (IsaPD) was promptly initiated. After two courses of IsaPD, significant remission was achieved and the neuronal symptoms completely resolved. When excessive serum levels of clonotypic free light chains are noted, their significance should be carefully assessed even when plasma cell propagation in the bone marrow is not observed. In such cases, hematologists should search for extramedullary proliferation of plasma cells, including in the immune-privileged central nervous system.

Primary plasma cell leukemia in Latin America: demographic, clinical, and prognostic characteristics. A study of GELAMM group

Primary plasma cell leukemia (pPCL) is an infrequent and aggressive plasma cell disorder. The prognosis is still very poor, and the optimal treatment remains to be established. A retrospective, multicentric, international observational study was performed. Patients from 9 countries of Latin America (LATAM) with a diagnosis of pPCL between 2012 and 2020 were included. 72 patients were included. Treatment was based on thalidomide in 15%, proteasome inhibitors (PI)-based triplets in 38% and chemotherapy plus IMIDs and/or PI in 29%. The mortality rate at 3 months was 30%. The median overall survival (OS) was 18 months. In the multivariate analysis, frontline PI-based triplets, chemotherapy plus IMIDs and/or PI therapy, and maintenance were independent factors of better OS. In conclusion, the OS of pPCL is still poor in LATAM, with high early mortality. PI triplets, chemotherapy plus IMIDs, and/or PI and maintenance therapy were associated with improved survival.

How to Manage Patients with Lenalidomide-Refractory Multiple Myeloma

Although lenalidomide-based combinations, such as lenalidomide plus a proteasome inhibitor or an anti-CD38 monoclonal antibody, improve the overall response rate, progression-free survival, and overall survival of patients with relapsed/refractory multiple myeloma (RRMM), there is a tendency to use these regimens as a frontline treatment. This strategy has led to the development of refractoriness early in the disease course, usually after the patient's first treatment. Since lenalidomide-free regimens have so far shown limited efficacy in lenalidomide-refractory patients, there is an unmet need for other treatment options. In this review, we discuss the therapeutic options available to treat the general population of lenalidomide-refractory patients (mono, double and triple refractory) and the subpopulation of patients with other high-risk features such as renal failure, extramedullary disease, and high-risk cytogenetics. Moreover, new promising individual therapies and the possible impact of immunotherapy in RRMM patients are debated.

The clinical characteristics and prognosis of patients with primary plasma cell leukemia (pPCL) according to the new IMWG definition criteria

Recently, the definition of primary plasma cell leukemia (pPCL) has been revised as the presence of circulating plasma cells (CPCs) ≥5% in peripheral blood smear. Consequently, the clinical features and prognosis of this aggressive disease can be truly identified by the larger patient cohort. Herein, we identified 158 new-defined pPCL patients among 2,266 MM patients (7.0%), and such prevalence doubled the previous estimate. Our study firstly provided solid support for the application of the new definition. We also found that cytopenias and adverse prognostic biomarkers were more common in new-defined pPCL compared with MM (p < 0.05). Besides, the patients receiving proteasome inhibitors based regimen in combination with stem cell transplantation could experience a considerable survival benefit. Strikingly, we showed that the presence of conventional high-risk cytogenetic abnormalities in pPCL didn't exert a great prognostic effect like MM, while elevated LDH reflecting tumor cells proliferation rate was the only independent predictor.

Lenalidomide, bortezomib and dexamethasone induction therapy for the treatment of newly diagnosed multiple myeloma: a practical review

For patients with newly diagnosed multiple myeloma, survival outcomes continue to improve significantly: however, nearly all patients will relapse following induction treatment. Optimisation of induction therapy is essential to provide longer term disease control and the current standard of care for most patients incorporates an immunomodulatory agent and proteasome inhibitor, most commonly lenalidomide and bortezomib in combination with dexamethasone (RVD), with maintenance until progression. Historically there has been limited access to RVD as an induction strategy outside of the United States; fortunately, there is now increasing access worldwide. This review discusses the rationale for use of RVD as induction therapy and aims to provide guidance in prescribing this regimen in order to optimise efficacy while minimising the toxicities of treatment. We also highlight the increasing evidence for the utility of addition of a monoclonal antibody to the RVD backbone to deepen responses and potentially provide longer disease control.

Causes of death in primary plasma cell leukemia differ from multiple myeloma: A STROBE-compliant descriptive study based on SEER database

The primary plasma cell leukemia (pPCL) is a rare but aggressive variant of multiple myeloma (MM). Few studies have focused on the differences in the causes of death between pPCL and MM. This study aimed to compare and evaluate the causes of death of patients with pPCL and MM. The data were collected from the Surveillance Epidemiology, and End Results (SEER) database. The demographic characteristics, survival, and causes of death in pPCL and MM patients were evaluated and compared. The competing risk regression model was performed to predict the cause of death. Between 1975 and 2009, the overall mortality rate was 96.13% and 88.71% for pPCL and MM, and the median survival was 9 and 26 months, respectively. In pPCL, leukemia caused 45.05% of the deaths, followed by myeloma (38.83%). In MM, myeloma was the leading cause of death, accounting for 74.89% of the deaths. Older age at diagnosis was a risk factor for dying of leukemia in pPCL patients (HR = 1.49, 95% CI: 1.16-1.91), while older age at death was associated with reduced risk (HR = 0.67, 95% CI: 0.52-0.86). Although the survival of pPCL patients increased with time periods of diagnosis since 1975 to 2009, the risk of dying of leukemia increased with the periods. For MM, most of the demographic characteristics were found to have independently predicting influence on the cause of death. Patients with pPCL and MM had distinct causes of death. Leukemia was the leading and the most serious cause of death in pPCL patients. The demographic factors could not predict the causes of death in pPCL. More large-scale and multi-center studies are needed to evaluate the effect of novel agents in pPCL patients, especially for patients who have progressed to leukemia.

Perspectives on the Risk-Stratified Treatment of Multiple Myeloma

The multiple myeloma treatment landscape has changed dramatically. This change, paralleled by an increase in scientific knowledge, has resulted in significant improvement in survival. However, heterogeneity remains in clinical outcomes, with a proportion of patients not benefiting from current approaches and continuing to have a poor prognosis. A significant proportion of the variability in outcome can be predicted on the basis of clinical and biochemical parameters and tumor-acquired genetic variants, allowing for risk stratification and a more personalized approach to therapy. This article discusses the principles that can enable the rational and effective development of therapeutic approaches for high-risk multiple myeloma.

Risk factors of acute kidney injury during BCMA CAR-T cell therapy in patients with relapsed/refractory multiple myeloma

OBJECTIVE

To explore the risk factors of acute kidney injury (AKI) during B cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T cell therapy in patients with relapsed/refractory multiple myeloma (MM).

METHODS

The clinical data of 99 patients with relapsed/refractory MM who received BCMA CAR-T cell therapy in the First Affiliated Hospital of Zhejiang University School of Medicine from July 2018 to December 2021 was retrospectively analyzed. Dynamic changes of renal function before and after chemotherapy preconditioning and after CAR-T cell infusion were observed. Logistic regression was used to analyze the independent risk factors associated with the occurrence of AKI.

RESULTS

Among 99 patients, the AKI occurred in 25 cases with an incidence rate of 25.3%, and the median time was 8.0 (5.5,11.0) d. The AKI grade 1, 2 and 3 accounted for 8.0%, 12.0% and 36.0%, respectively. Logistic regression analysis showed that serum creatinine (SCr) after chemotherapy preconditioning ( OR=1.020, P<0.001), and the grade of cytokine release syndrome (CRS) ( OR=6.501, P<0.01) were independent risk factors for AKI during treatment. The area under the ROC curve (AUC) of SCr after chemotherapy preconditioning in predicting AKI was 0.800 (95% CI: 0.694-0.904, P<0.001); using 83.0 μmol/L as cut-off value, the sensitivity, specificity and Youden index of SCr were 72.0%, 80.8% and 0.528, respectively. The incidence of AKI in patients with grade 3-4 CRS was 39.1%, while that was 13.2% in patients with CRS<grade 3 ( χ ²=8.767, P<0.01).

CONCLUSIONS

AKI mostly occurred within 15.0 d after CAR-T cell infusion, causing transient severe renal damage. Patients with abnormal renal function after chemotherapy preconditioning should be alert to the occurrence of AKI, and attention should be paid to the management of the CRS.

Immunoproteasome Activity in Chronic Lymphocytic Leukemia as a Target of the Immunoproteasome-Selective Inhibitors

Targeting proteasome with proteasome inhibitors (PIs) is an approved treatment strategy in multiple myeloma that has also been explored pre-clinically and clinically in other hematological malignancies. The approved PIs target both the constitutive and the immunoproteasome, the latter being present predominantly in cells of lymphoid origin. Therapeutic targeting of the immunoproteasome in cells with sole immunoproteasome activity may be selectively cytotoxic in malignant cells, while sparing the non-lymphoid tissues from the on-target PIs toxicity. Using activity-based probes to assess the proteasome activity profile and correlating it with the cytotoxicity assays, we identified B-cell chronic lymphocytic leukemia (B-CLL) to express predominantly immunoproteasome activity, which is associated with high sensitivity to approved proteasome inhibitors and, more importantly, to the immunoproteasome selective inhibitors LU005i and LU035i, targeting all immunoproteasome active subunits or only the immunoproteasome β5i, respectively. At the same time, LU102, a proteasome β2 inhibitor, sensitized B-CLL or immunoproteasome inhibitor-inherently resistant primary cells of acute myeloid leukemia, B-cell acute lymphoblastic leukemia, multiple myeloma and plasma cell leukemia to low doses of LU035i. The immunoproteasome thus represents a novel therapeutic target, which warrants further testing with clinical stage immunoproteasome inhibitors in monotherapy or in combinations.

Targeted Drug Delivery for the Treatment of Blood Cancers

Blood cancers are a type of liquid tumor which means cancer is present in the body fluid. Multiple myeloma, leukemia, and lymphoma are the three common types of blood cancers. Chemotherapy is the major therapy of blood cancers by systemic administration of anticancer agents into the blood. However, a high incidence of relapse often happens, due to the low efficiency of the anticancer agents that accumulate in the tumor site, and therefore lead to a low survival rate of patients. This indicates an urgent need for a targeted drug delivery system to improve the safety and efficacy of therapeutics for blood cancers. In this review, we describe the current targeting strategies for blood cancers and recently investigated and approved drug delivery system formulations for blood cancers. In addition, we also discuss current challenges in the application of drug delivery systems for treating blood cancers.

The Cytogenetic Profile of Primary and Secondary Plasma Cell Leukemia: Etiopathogenetic Perspectives, Prognostic Impact and Clinical Relevance to Newly Diagnosed Multiple Myeloma with Differential Circulating Clonal Plasma Cells

Plasma cell leukemia (PCL) is a rare and aggressive plasma cell dyscrasia that may appear as de-novo leukemia (pPCL) or on the basis of a pre-existing multiple myeloma (MM), called secondary plasma cell leukemia (sPCL). In this prospective study, we have applied a broad panel of FISH probes in 965 newly diagnosed MM (NDMM) and 44 PCL cases of both types to reveal the particular cytogenetic differences among the three plasma cell dyscrasias. In order to evaluate the frequency and patterns of clonal evolution, the same FISH panel was applied both at diagnosis and at the time of first relapse for 81 relapsed MM patients and both at MM diagnosis and during sPCL transformation for the 19 sPCL cases described here. pPCL was characterized by frequent MYC translocations and t(11;14) with a 11q13 breakpoint centered on the MYEOV gene, not commonly seen in MM. sPCL had a higher number of FISH abnormalities and was strongly associated with the presence of del(17p13), either acquired at the initial MM stage or as a newly acquired lesion upon leukemogenesis in the context of the apparent clonal evolution observed in sPCL. In clinical terms, sPCL showed a shorter overall survival than pPCL with either standard or high-risk (t(4;14) and/or t(14;16) and/or del(17p13) and/or ≥3 concomitant aberrations) abnormalities (median 5 months vs. 21 and 11 months respectively, p < 0.001), suggesting a prognostic stratification based on cytogenetic background. These observations proved relevant in the NDMM setting, where higher levels of circulating plasma cells (CPCs) were strongly associated with high-risk cytogenetics (median frequency of CPCs: 0.11% of peripheral blood nucleated cells for high-risk vs. 0.007% for standard-risk NDMM, p < 0.0001). Most importantly, the combined evaluation of CPCs (higher or lower than a cut-off of 0.03%), together with patients’ cytogenetic status, could be used for an improved prognostic stratification of NDMM patients.

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.

High-output heart failure associated with primary plasma cell leukaemia due to arteriovenous shunting: a case report

Background

Primary plasma cell leukaemia is rarely associated with high-output heart failure, and the underlying mechanism is not well understood. We encountered a rare case of high-output heart failure caused by primary plasma cell leukaemia. Its underlying mechanism was clarified through imaging studies.

Case summary

A 49-year-old man with no specific medical history was admitted to our hospital because of heart failure that did not improve with diuretic therapy. His condition was diagnosed as high-output heart failure and primary plasma cell leukaemia after admission. Extensive bone involvement in primary plasma cell leukaemia and arteriovenous shunts in the same lesion were suspected after various imaging studies. The first cycle of chemotherapy with bortezomib, adriamycin, and dexamethasone led to remission of primary plasma cell leukaemia and improved heart failure symptoms. The patient received further chemotherapy in addition to autologous peripheral blood stem cell transplantation and maintenance therapy and had no recurrence of pPCL or heart failure for 1 year to date.

Discussion

Primary plasma cell leukaemia can be associated with high-output heart failure, which is caused by arteriovenous shunting at the lesion site with diffuse bone involvement. Imaging studies may lead to the early diagnosis of aetiology and treatment of patients with high-output heart failure associated with primary plasma cell leukaemia.

How to Treat High-Risk Myeloma at Diagnosis and Relapse

Survival in multiple myeloma has improved greatly during the past 2 decades, but this change has primarily benefited patients who have standard-risk disease. Patients with high-risk disease remain a challenge to diagnose and treat. To improve their clinical outcomes, it is imperative to develop tools to readily identify them and to provide them with the most effective available treatments. The most widely used stratification system, the revised International Staging System, incorporates serum β-2 microglobulin, albumin, lactate dehydrogenase, and high-risk chromosomal abnormalities [del(17p), t(4;14), and t(14;16)]. Recent updates have included mutational status and chromosome 1q abnormalities. Plasma cell leukemia, extramedullary disease, circulating plasma cells, renal failure, and frailty are also associated with poor outcome. The treatment approach for a newly diagnosed patient with high-risk multiple myeloma should include induction therapy, autologous stem cell transplantation if appropriate, and maintenance therapy. Triplet therapy with a proteasome inhibitor, immunomodulatory drug, and steroid, with or without an anti-CD38 antibody, should be considered for induction, along with a proteasome inhibitor and/or immunomodulatory drug for maintenance. Aiming for a deep and sustained response is important. Similar principles apply at relapse, with close monitoring of response, especially extramedullary disease and active management of side effects, so that patients can continue therapy and benefit from treatment. Immune-based therapies, including autologous CAR T-cell-based therapies and bispecific antibodies, show promising activity in relapsed disease and are being actively explored in earlier disease settings. As the prognosis for high-risk disease remains poor, the future goal for this patient group is to develop specific clinical trials to explore novel approaches and therapies efficiently.