[Efficacy and safety of first-line treatment with anti-CD38 monoclonal antibody-based regimen for primary plasma cell leukemia].

Objective: To analyze the efficacy and safety of first-line treatment with an anti-CD38 monoclonal antibody regimen for primary plasma cell leukemia (pPCL). Methods: Patients diagnosed with pPCL from December 1st, 2018 to July 26th, 2023, receiving first-line treatment of anti-CD38 monoclonal antibody-based regimens across multiple centers including Peking University People's Hospital, Fuxing Hospital of Capital Medical University, Qingdao Municipal Hospital, Shengjing Hospital of China Medical University, Handan Central Hospital, the First Affiliated Hospital of Harbin Medical University, the Fourth Hospital of Hebei Medical University and General Hospital of Ningxia Medical University were consecutively included. A total of 24 pPCL patients were included with thirteen being male and eleven being female. The median age [M(Q1, Q3)] was 60 (57, 70) years. Patients were grouped according to peripheral blood plasma cell (PBPC) percentage [5%-19% (n=14) vs ≥20% (n=10)]. Last follow-up date was September 26th, 2023. The median follow-up period was 9.1 (4.2, 15.5) months. Patients' data related with clinical baseline characteristics, efficacy, survival and safety were retrospectively collected. Cox proportional hazards regression model was used to analyze risk factors associated with survival. Results: Among 24 pPCL patients, 16 (66.7%) patients had anemia at diagnosis, 13(54.2%) patients had thrombocytopenia, 8 (33.3%) patients had a baseline estimated glomerular filtration rate (eGFR)<40 ml·min-1·(1.73m2)-1, 13 (54.2%) patients had elevated lactate dehydrogenase (LDH) levels. The median PBPC percentage was 16% (8%, 26%) . Fluorescence in situ hybridization testing indicated that patients harboring 17p deletion, t(4;14) or t(14;16) were 6 (25.0%), 4 (16.7%) and 4 (16.7%), respectively. The overall response rate was 83.3% (20/24). The median progression-free survival (PFS) was 20.5 (95%CI: 15.8-25.2) months, and the median overall survival (OS) was not reached. Estimated 1-year and 2-year PFS and OS rates were 75.0% and 89.1%, 37.5% and 53.4%, respectively. The median PFS and OS for patients with PBPC percentages 5%-19% and≥20% were not reached and 20.5 (95%CI:15.7-25.3) months, 17.8 months and not reached, respectively. There was no significant statistical difference of PFS and OS between two groups (all P>0.05). Multivariate Cox regression analysis showed that 1p32 deletion was the risk factor associated with PFS (HR=7.7, 95%CI: 1.1-54.9, P=0.043). Seventeen patients (70.8%) developed grade 3-4 hematologic toxicities. Twelve patients (50.0%) developed grade 3-4 thrombocytopenia. Sixteen patients (66.7%) developed infection. All hematologic toxicities and infections were improved after supportive treatment. Conclusion: First-line treatment with anti-CD38 monoclonal antibody-based therapy for pPCL is effective and safe.

Complete response following treatment of plasma cell leukemia with venetoclax and dexamethasone: A case report.

INTRODUCTION: Plasma cell leukemia (PCL) is a rare but aggressive variant of multiple myeloma (MM) with a poor prognosis. Due to the limited number of prospective clinical trials studying PCL, treatment options are often extrapolated from data available for the treatment of MM. Venetoclax has recently demonstrated antimyeloma activity in patients with relapsed/refractory MM carrying the t(11;14) translocation. However, few cases have reported the analogous efficacy of venetoclax in PCL. CASE REPORT: A 64-year-old Caucasian male developed relapsed PCL despite treatment with hyperCD (hyperfractionated cyclophosphamide and dexamethasone) and Dara-KRd (daratumumab, carfilzomib, lenalidomide, dexamethasone). Due to the refractory nature of his disease and the presence of a t(11:14) translocation, the patient was subsequently initiated on venetoclax 400 mg daily and dexamethasone 4 mg once weekly. MANAGEMENT AND OUTCOME: The patient achieved a complete response by International Myeloma Working Group criteria three months after initiating venetoclax-dexamethasone, including a repeat bone marrow biopsy that showed no abnormal plasma cells. He successfully underwent consolidation with melphalan-based autologous stem cell transplantation. He remains disease-free 9 months after venetoclax initiation. DISCUSSION: Combination all-oral therapy with venetoclax and dexamethasone can induce deep hematologic responses in patients with relapsed/refractory PCL carrying the t(11;14) translocation.

[Rapid response of secondary plasma cell leukemia after carfilzomib and dexamethasone therapy].

An 83-year-old man was admitted to our hospital due to a recurrence of multiple myeloma, accompanied by the appearance of plasma cells in the peripheral blood (PB). Subsequently, he was diagnosed with secondary plasma cell leukemia (sPCL). A chemotherapy regimen of carfilzomib and dexamethasone (Cd) combination therapy was selected, and 15 days later, plasma cells completely disappeared from the PB. Cd therapy was continued, and the free kappa chain levels normalized. Three months later, M-protein could not be detected using serum electrophoresis. This is a valuable report wherein Cd combination therapy was successful in treating sPCL.

[Multiple extramedullary plasmacytomas responding to a reduced dose of carfilzomib following drug-induced thrombotic microangiopathy].

Herein, we report the findings of a 79-year-old male patient who presented with multiple extramedullary plasmacytomas following a relapse of primary plasma cell leukemia. He developed thrombotic microangiopathy (TMA) while receiving carfilzomib, lenalidomide, and dexamethasone (KLd) therapy. He was diagnosed with plasma cell leukemia 3 years ago; he demonstrated a very good partial response (VGPR) after undergoing two regimens, including either bortezomib or lenalidomide, and he had been followed up without any other treatment due to complications of infection. Following relapse, KLd was initiated. On day 7 of KLd, TMA developed; therefore, the treatment was discontinued. The TMA improved only with the discontinuation of KLd. A reduced dose of KLd was readministered; the TMA did not relapse. He demonstrated VGPR after three courses of reduced-KLd; he has since remained in remission through ten courses. Therefore, carfilzomib therapy may be useful in relapsing and refractory cases. Drug-induced TMA has been reported to be caused by either immune-mediated or dose-dependent toxicity mechanisms. In patients who develop dose-dependent TMA with carfilzomib, dose reduction could be considered in cases showing an effective response to the treatment.

A successful case of venetoclax-based therapy in relapsed/refractory secondary plasma cell leukemia.

BACKGROUND: Secondary plasma cell leukemia (sPCL) patients typically are either refractory to conventional therapies or have short remissions to drug regimens used in multiple myeloma (MM), which highlights sPCL's aggressive nature and association with advanced stage disease. t(11,14) is correlated with increased BCL-2 expression, which makes it a cytogenic marker of interest for use of the BCL-2 inhibitor venetoclax. Little data of venetoclax's use has been published in plasma cell leukemia. We present a case of a refractory/relapsed sPCL patient displaying t(11,14) who achieved a very good partial response (VGPR) from venetoclax therapy in combination with dexamethasone and bortezomib. CASE REPORT: Our case describes a 67-year-old male initially diagnosed with IgG kappa MM in 2013, which transformed into non-secretory secondary plasma cell leukemia. Over a two-year period, despite responses to various therapies, the patient continued to experience relapses and exhausted options of novel agents seen in MM treatment. The patient was started on venetoclax in combination with bortezomib and oral dexamethasone. MANAGEMENT AND OUTCOME: Due to the patient's disease transformation into a non-secretory form of sPCL, PET/CT scans were relied upon to monitor disease progression. The PET/CT scan after three months of venetoclax combination treatment showed a very good partial response to therapy, with near resolution of metabolically active osseous disease. DISCUSSION: The success of venetoclax-based therapy in achieving a very good partial response suggests its utility in relapsed/refractory sPCL patients, who have exhausted various combinations of drug regimens used in treatment of MM and have historically poor survival outcomes.

[Successful disease control of plasma cell leukemia by the treatment comprising proteasome inhibitors, followed by daratumumab, lenalidomide, and dexamethasone therapy].

A 59-year-old woman was referred by her family doctor to our hospital owing to anemia, nausea, and malaise. She was diagnosed with primary plasma cell leukemia based on her laboratory and morphologic findings. She was treated with high dose of dexamethasone; cyclophosphamide, bortezomib, and dexamethasone; and carfilzomib, lenalidomide, and dexamethasone. She achieved partial treatment response. We switched her treatment to daratumumab, lenalidomide, and dexamethasone (DRd) owing to progression of peripheral neuropathy. Bone marrow examination performed after 15 courses of DRd revealed minimal residual disease-negative status. Sequential multidrug combination chemotherapies may be related to long-term successful disease control.

Early relapse after complete remission of primary plasma cell leukaemia manifesting clonal evolution: A case report.

INTRODUCTION: Plasma cell leukaemia (PCL) is a rare variant of multiple myeloma. We report a case of PCL to demonstrate the clonal evolution, resulting in disease relapse after achieving complete remission, and its aggressive nature of the disease, leading to poor clinical outcome. CASE REPORT: A 69-year-old man presented with a three-day-history of worsening generalized body weakness, poor oral intake, nausea, significant loss of weight and lower back pain. He was diagnosed as primary PCL, based on hypercalcaemia, renal insufficiency, anaemia, thrombocytopenia, lytic bone lesions, 24% abnormal plasma cells in peripheral blood, immunophenotype of clonal plasma cells which were positive for CD38, CD138 and CD56 markers with kappa light chain restriction, 49% abnormal plasma cells in bone marrow, monoclonal paraprotein (IgG kappa) in serum and urine, and positive IGH rearrangement (Fluorescence in-situ hybridisation, FISH). He achieved complete remission after four cycles of Bortezomib-based therapy. There was a plan for high-dose therapy plus autologous haematopoietic cell transplantation. A month later, the disease relapsed, as evidenced by 94% abnormal plasma cells in his bone marrow aspirate, complex karyotype and abnormal FISH results. He passed away a few days later, from severe septicaemia. Time-to-progression of disease was 1 month and overall survival was 5 months. DISCUSSION: This case report illustrates the clonal evolution and aggressive nature of primary PCL with older age at presentation, leading to a shorter duration of remission and overall survival.

Survival outcomes of patients with primary plasma cell leukemia (pPCL) treated with novel agents.

BACKGROUND: Primary plasma cell leukemia (pPCL) is an aggressive plasma cell disorder characterized by circulating plasma cells and a poor prognosis. Although patients who have pPCL benefit from the use of stem cell transplantation (SCT) and novel agents, their prognosis remains inferior to that of patients who have myeloma. METHODS: This was a retrospective analysis of 38 consecutive patients with pPCL who were diagnosed between October 2005 and July 2016 and were registered in the Winship Cancer Institute of Emory University database. Baseline characteristics as well as data about treatment and survival outcomes were collected. RESULTS: The median patient age at diagnosis was 58 years. All patients received a bortezomib-based induction regimen, and 92% received both bortezomib and an immunomodulatory drug (thalidomide or lenalidomide); in addition, 74% of patients underwent autologous SCT (ASCT), and 61% received maintenance therapy. The best response to first-line therapy was a partial response or better in 87% of patients, and 45% had a complete response (CR). The achievement of ≥CR was a predictor for prolonged progression-free survival (PFS) and overall survival (OS). The median PFS was 20 months, and the median OS was 33 months. PFS was prolonged in patients who underwent ASCT compared with those who did not undergo ASCT (25 vs 6 months; P = .004), and patients who received maintenance therapy after ASCT had prolonged median PFS (27 vs 11 months; P = .03) and a trend toward prolonged OS (median, 38 vs 22 months; P = .06) compared with those who did not receive maintenance therapy. CONCLUSIONS: The current data support the use of regimens combining novel agents in the upfront treatment of patients with pPCL as well as the role of ASCT and maintenance therapy for long-term disease control.

Pixantrone demonstrates significant in vitro activity against multiple myeloma and plasma cell leukemia.

Treatment results for multiple myeloma and plasma cell leukemia have considerably improved, but cure remains elusive and establishing new therapeutic approaches constitutes a major unmet clinical need. We analyzed the anti-myeloma properties of the aza-anthracenedione pixantrone which has been successfully used in a phase III study for the treatment of patients with aggressive non-Hodgkin's lymphoma as monotherapy as well as in combination regimes in vitro and in an adapted in vivo model (ex ovo chicken chorioallantoic membrane (CAM) assay). Pixantrone significantly inhibited proliferation and metabolic activity of all investigated myeloma cell lines. Importantly, anti-myeloma effects were more pronounced in tumor cell lines than in stromal cells, mesenchymal stem cells, and peripheral blood mononuclear cells of healthy controls. Apoptosis of myeloma cell lines was observed only after a 7-day incubation period, indicating a fast cytostatic and a slower cytotoxic effect of this drug. Pixantrone reduced the viability of primary plasma cells of patients and induced downregulation of myeloma-cell growth in the CAM assay. Additionally, we demonstrate in vitro synergism between pixantrone and the histone deacetylase inhibitor panobinostat with respect to its anti-proliferative features. From these data, we conclude that systematic investigations of the clinical usefulness of pixantrone in the framework of controlled clinical trials are clearly indicated (e.g., in penta-refractory patients).

Combination therapy incorporating Bcl-2 inhibition with Venetoclax for the treatment of refractory primary plasma cell leukemia with t (11;14).

Primary plasma cell leukemia (pPCL) is the most aggressive form of the plasma cell (PC) malignancy, multiple myeloma (MM). It has been commonly associated with the presence of a chromosome translocation involving the immunoglobulin heavy chain (IgH) locus on 14q32, that is t (11;14). Results from early phase clinical trials utilizing the selective Bcl-2 inhibitor, venetoclax, as a single agent in patients with relapsed MM have had remarkable efficacy among patients with t (11;14) abnormality. The present case demonstrates the ability of a combination regimen incorporating Bcl-2 inhibition with daratumumab, bortezomib, venetoclax, and dexamethasone to induce a rapid and very deep hematologic response in a pPCL patient with t (11;14), even in a setting of very refractory disease. This case highlights the need to further study Bcl-2 inhibition-based therapy as an option for therapy in patients with pPCL with t (11;14).

Histone deacetylase inhibitors in plasma cell leukemia treatment: effect of bone marrow microenvironment.

In the presented study we analysed the effect of histone deacetylase inhibitors (HDACi) suberoylanilide hydroxamic acid (SAHA) and valproic acid (VPA) on human plasma cell leukemia (PCL) cell line UHKT-944 in the presence of bone marrow microenvironment (BMM). For the analysis, the cells were cultured alone, with bone marrow stromal cells (BMSCs), with extracellular matrix (ECM) components or with interleukin-6, and treated with varied concentrations of SAHA and VPA for 24/48 hours. To study the effect of HDACi, we investigated cell proliferation, apoptosis, cell cycle and changes in selected signalling pathways. We found that both SAHA and VPA induced apoptosis, but had no effect on the cell cycle distribution of UHKT-944 cells. Investigation of the antiproliferative effect of SAHA and VPA revealed that BMSCs and high concentration of interleukin-6 had partial protective effect against SAHA or both inhibitors, respectively. No effect of ECM components on the efficiency of HDACi was observed. We further revealed that VPA down-regulated STAT3 phosphorylation while both inhibitors decreased Akt phosphorylation. In conclusion, VPA and SAHA might represent an additional therapeutic strategy in the PCL treatment. Protective effect of BMM should be taken into account when investigating prospective therapeutic agents against plasma cell disorders.

Trends in survival of patients with primary plasma cell leukemia: a population-based analysis.

Primary plasma cell leukemia (pPCL) is a rare malignancy with an aggressive course and poor outcome. There has been significant improvement in the survival of multiple myeloma patients over the past decade as a result of incorporating autologous stem cell transplantation (ASCT) and novel agents into treatment regimens. However, it is unknown whether these therapies have had a similar impact on the survival of patients with pPCL. We conducted an analysis of the Surveillance, Epidemiology, and End Results database to evaluate the trends in survival of 445 patients with pPCL between 1973 and 2009. The widespread availability of ASCT and use of novel agents in the upfront setting of multiple myeloma and pPCL began after 1995 and 2006, respectively. The median overall survival based on periods of diagnosis were 5, 6, 4, and 12 months for those diagnosed during 1973-1995, 1996-2000, 2001-2005, and 2006-2009, respectively (P = .001). Thus, the current study confirms the recent survival improvement in pPCL within a large US population that may be associated with the use of better therapeutic strategies.

Primary Plasma Cell Leukemia in the Era of Novel Agents: A Multicenter Study of the Japanese Society of Myeloma.

We investigated the treatment and outcome of Japanese patients with primary plasma cell leukemia (pPCL) in the era of novel agents and analyzed the risk factors affecting survival. Among 3,318 patients with symptomatic multiple myeloma (MM), 38 patients were diagnosed with pPCL. The median overall survival (OS) of the pPCL patients was 2.85 years, which was significantly extended compared with that in previous reports. The proportion of patients treated with novel agents was 61%. The OS of the patients treated with novel agents was significantly extended compared with that of patients treated without novel agents according to the generalized Wilcoxon test (2.85 vs. 1.16 years, p = 0.049). This statistical finding suggests that treatment with novel agents could have prevented early death in the patients with pPCL. Age was the only statistically significant prognostic factor associated with an inferior OS (hazard ratio 4.57). Five patients received maintenance therapy with novel agents, and their OS tended to be longer than that of the other patients without maintenance (4.45 vs. 2.85 years). Unlike MM, OS for pPCL has not been improved significantly over the last decade, especially in elderly patients. Therefore, it is important to establish the treatment strategy, particularly after induction treatment.

Molecular Classification and Pharmacogenetics of Primary Plasma Cell Leukemia: An Initial Approach toward Precision Medicine.

Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM) which may represent a valid model for high-risk MM. This disease is associated with a very poor prognosis, and unfortunately, it has not significantly improved during the last three decades. New high-throughput technologies have allowed a better understanding of the molecular basis of this disease and moved toward risk stratification, providing insights for targeted therapy studies. This knowledge, added to the pharmacogenetic profile of new and old agents in the analysis of efficacy and safety, could contribute to help clinical decisions move toward a precision medicine and a better clinical outcome for these patients. In this review, we describe the available literature concerning the genomic characterization and pharmacogenetics of plasma cell leukemia (PCL).

Treatment with bortezomib-based regimens improves overall response and predicts for survival in patients with primary or secondary plasma cell leukemia: Analysis of the Greek myeloma study group.

Plasma cell leukemia (PCL) is a rare and aggressive plasma cell disorder, with poor outcome. Bortezomib-based regimens (BBR) are highly effective in myeloma, but there is limited information about their efficacy and safety in PCL. Thus, we retrospectively collected data from 42 consecutive PCL patients (25 with primary PCL-pPCL and 17 with secondary PCL-sPCL) to explore the role of BBR in this entity. BBR were administered in 29 of 42 patients, while 6 of 25 patients with pPCL underwent autologous transplantation. Objective response (≥partial response) was significantly higher in patients treated with BBR versus conventional therapies (69% vs. 30.8%, P = 0.04); 27.5% of patients treated with BBR achieved at least very good partial response (vgPR). The highest ORR was observed in pPCL patients treated with BBR (88.9%; ≥vgPR: 33.3%). In BBR-group, grade 3 of 4 hematological, neurological and renal toxicity and neutropenic infections were observed in 41.4%, 7%, 3.4%, and 31%, respectively. With a median follow-up of 51 months, median overall survival (OS) for patients treated with BBR versus conventional therapies was 13 versus 2 months (P < 0.007). Median OS of patients with pPCL and sPCL treated with BBR was 18 and 7 months, respectively (P < 0.001). In the multivariate analysis normal PLTs, treatment with BBR and high quality response were the only powerful predictors for survival. Our study carrying the longest reported median follow-up, demonstrated that treatment of PCL with BBR induces high response rates and prolongs survival over conventional therapies, regardless of additional autologous transplantation rescue or established high risk features, with manageable toxicity.