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The treatment of relapsed/refractory multiple myeloma (MM) has evolved to include several new options. These include new combinations with second generation proteasome inhibitors (PI); second generation immunomodulators, monoclonal antibodies, CAR T cells, bispecific antibodies, selinexor, venetoclax, and many others. Most patients with MM undergo several cycles of remissions and relapse, and therefore need multiple lines of combination therapies. Selecting treatment options for relapsed/refractory MM requires consideration of resistance status to specific classes, and patient-specific factors such as age and other comorbidities should be considered. The NCCN Guidelines for MM provide a framework on which to base decisions regarding workup, treatment, and follow-up of newly diagnosed and previously treated MM. This manuscript outlines the recommendations from NCCN Guidelines for MM specific to relapsed/refractory disease.

Multiple myeloma (MM) is a common hematological malignancy that has fostered several new therapeutic approaches to combat newly diagnosed or relapsed MM. While the field has advanced over the past 2 decades, the majority of patients will develop resistance to these treatments, causing the need for new therapeutic targets. SLAMF7 is an attractive therapeutic target in multiple myeloma, and a monoclonal antibody that targets SLAMF7 has shown consistent beneficial outcomes in clinical trials to date. In this review, we will focus on the structure and regulation of SLAMF7 and its mechanism of action. The most recent clinical trials will be reviewed to further understand the clinical implications and improve the prognosis of MM. Furthermore, the efficacy of anti-SLAMF7 monoclonal antibodies combined with standard therapies and possible resistance mechanisms will be discussed. This review aimed to provide a detailed summary of the role of SLAMF7 in the pathogenesis of patients with MM and the rationale for further investigation into SLAMF7-mediated molecular pathways associated with MM development.

Retinoid X receptor ( RXR ) heterodimerizes with the PPAR nuclear hormone receptor and regulates its downstream events. We investigated the effects of RXR agonists (LG100754, bexarotene, AGN194204, and LG101506) on lenalidomide's anti-myeloma activity, T cell functions, and the level of glucose and lipids in vivo. Genetic overexpression and CRISPR/Cas9 knockout experiments were conducted in multiple myeloma (MM) cell lines and Jurkat T cell lines to determine the roles of CRBN in RXR -agonist mediated effects. A xenograft mouse model of MM was established to determine the combination effect of LG100754 and lenalidomide. The combination of RXR agonists and lenalidomide demonstrated synergistic activity in increasing CRBN expression and killing myeloma cells. Mechanistically, the RXR agonists reduced the binding of PPARs to the CRBN promoter, thereby relieving the repressor effect of PPARs on CRBN transcription. RXR agonists downregulated the exhaustion markers and increased the activation markers of Jurkat T cells and primary human T cells. Co-administration of LG100754 and lenalidomide showed enhanced anti-tumor activity in vivo. LG100754 retained its glucose- and lipid-lowering effects. RXR agonists demonstrate potential utility in enhancing drug sensitivity and T-cell function in the treatment of myeloma.

Mitophagy plays an important role in maintaining mitochondrial homeostasis by clearing damaged mitochondria. Sphingosine kinase 2 (SK2), a type of sphingosine kinase, is an important metabolic enzyme involved in generating sphingosine-1-phosphate. Its expression level is elevated in many cancers and is associated with poor clinical outcomes. However, the relationship between SK2 and mitochondrial dysfunction remains unclear. We found that the genetic downregulation of SK2 or treatment with ABC294640, a specific inhibitor of SK2, induced mitophagy and apoptosis in multiple myeloma cell lines. We showed that mitophagy correlates with apoptosis induction and likely occurs through the SET/PP2AC/PARK2 pathway, where inhibiting PP2AC activity may rescue this process. Furthermore, we found that PP2AC and PARK2 form a complex, suggesting that they might regulate mitophagy through protein-protein interactions. Our study demonstrates the important role of SK2 in regulating mitophagy and provides new insights into the mechanism of mitophagy in multiple myeloma.

Multiple myeloma (MM) remains an incurable disease and there is an unmet medical need for novel therapeutic drugs that do not share similar mechanisms of action with currently available agents. Sphingosine kinase 2 (SK2) is an innovative molecular target for anticancer therapy. We previously reported that treatment with SK2 inhibitor opaganib inhibited myeloma tumor growth in vitro and in vivo in a mouse xenograft model. In the current study, we performed a phase I study of opaganib in patients with relapsed/refractory multiple myeloma (RRMM). Thirteen patients with RRMM previously treated with immunomodulatory agents and proteasome inhibitors were enrolled and treated with single-agent opaganib at three oral dosing regimens (250 mg BID, 500 mg BID, or 750 mg BID, 28 days as a cycle). Safety and maximal tolerated dose (MTD) were determined. Pharmacokinetics, pharmacodynamics, and correlative studies were also performed. Opaganib was well tolerated up to a dose of 750 mg BID. The most common possibly related adverse event (AE) was decreased neutrophil counts. There were no serious AEs considered to be related to opaganib. MTD was determined as at least 750 mg BID. On an intent-to-treat basis, one patient (7.7%) in the 500 mg BID dose cohort showed a very good partial response, and one other patient (7.7%) achieved stable disease for 3 months. SK2 is an innovative molecular target for antimyeloma therapy. The first-in-class SK2 inhibitor opaganib is generally safe for administration to RRMM patients, and has potential therapeutic activity in these patients. Clinicaltrials.gov: NCT02757326., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Many patients with multiple myeloma (MM) have comorbidities and are treated with PPAR agonists. Immunomodulatory agents (IMiDs) are the cornerstones for MM therapy. Currently, little is known about how co-administration of PPAR agonists impacts lenalidomide treatment in patients with MM. Here, we determined the effects of PPAR agonists on anti-myeloma activities of lenalidomide in vitro and in a myeloma xenograft mouse model. Genetic overexpression and CRISPR/cas9 knockout experiments were performed to determine the role of CRBN in the PPAR-mediated pathway. A retrospective cohort study was performed to determine the correlation of PPAR expression with the outcomes of patients with MM. PPAR agonists down-regulated CRBN expression and reduced the anti-myeloma efficacy of lenalidomide in vitro and in vivo. Co-treatment with PPAR antagonists increased CRBN expression and improved sensitivity to lenalidomide. PPAR expression was higher in bone marrow cells of patients with newly diagnosed MM than in normal control bone marrow samples. High PPAR expression was correlated with poor clinical outcomes. Our study provides the first evidence that PPARs transcriptionally regulate CRBN and that drug-drug interactions between PPAR agonists and IMiDs may impact myeloma treatment outcomes., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: In the single-arm, phase 1b/2 CARTITUDE-1 study, ciltacabtagene autoleucel (cilta-cel), an anti-B-cell maturation antigen chimeric antigen receptor T-cell (CAR-T) therapy, showed encouraging efficacy in US patients with multiple myeloma (MM) who previously received an immunomodulatory drug, proteasome inhibitor, and anti-CD38 monoclonal antibody (triple-class exposed)., Patients and Methods: A dataset of US patients refractory to an anti-CD38 monoclonal antibody (MAMMOTH) was used to identify patients who would meet eligibility for CARTITUDE-1 and received subsequent non-CAR-T therapy. The intent-to-treat (ITT) population in CARTITUDE-1 included patients who underwent apheresis (N = 113); the modified ITT (mITT) population was the subset who received cilta-cel (n = 97). Corresponding populations were identified from the MAMMOTH dataset: ITT population (n = 190) and mITT population of patients without progression/death within 47 days (median apheresis-to-cilta-cel infusion time) from onset of therapy (n = 122). Using 1:1 nearest neighbor propensity score matching to control for selected baseline covariates, 95 and 69 patients in CARTITUDE-1 ITT and mITT populations, respectively, were matched to MAMMOTH patients., Results: In ITT cohorts of CARTITUDE-1 vs. MAMMOTH, improved overall response rate (ORR; 84% vs. 28% [P < .001]) and longer progression-free survival (PFS; hazard ratio [HR], 0.11 [95% confidence interval (CI), 0.05-0.22]) and overall survival (OS; HR, 0.20 [95% CI, 0.10-0.39]) were observed. Similar results were seen in mITT cohorts of CARTITUDE-1 vs. MAMMOTH (ORR: 96% vs. 30% [P < .001]; PFS: HR, 0.02 [95% CI, 0.01-0.14]; OS: HR, 0.05 [95% CI, 0.01-0.22]) and with alternative matching methods., Conclusion: Cilta-cel yielded significantly improved outcomes versus real-world therapies in triple-class exposed patients with relapsed/refractory MM., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Although treatment outcomes of multiple myeloma patients have improved significantly during the last two decades, myeloma is still an incurable disease. There are newly emerging immunotherapies to treat multiple myeloma including monoclonal antibodies, antibody-drug conjugate, bispecific antibodies, and chimeric antigen receptor (CAR) T cell therapy. Impressive response rate and clinical efficacy in heavily pretreated myeloma patients led to the FDA approval of the first myeloma CAR-T therapy in March 2021. Among many different targets for myeloma CAR-T therapies, B Cell Maturation Antigen (BCMA) has been the most successful target so far, but other targets which can be used either for single-target or dual-target CAR-T's are actively being explored. Clinical efficacy and safety of current myeloma CAR-T therapies will be presented here. Potential mechanisms leading to resistance include clearance of CAR-T cells, antigenic escape, and immunosuppressive tumor microenvironment. Novel strategies to enhance myeloma CAR-T will also be described. In this article, we provide a comprehensive review of the current data and the future directions of myeloma CAR-T therapies., Competing Interests: Declaration of Competing Interest Taewoong Choi has served for the Janssen Biotech speaker bureau. Yubin Kang has served at the Sanofi-Genzyme Advisory panel and PSI advisory board., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The NCCN Guidelines for Multiple Myeloma provide recommendations for diagnosis, initial workup, treatment, follow-up, and supportive care for patients with various plasma cell neoplasms, including multiple myeloma. These NCCN Guidelines Insights highlight some of the important updates/changes specific to the treatment of patients with multiple myeloma in the 2022 version of the guidelines.

Multiple myeloma is a malignant neoplasm of plasma cells that accumulate in bone marrow, leading to bone destruction and marrow failure. This manuscript discusses the management of patients with solitary plasmacytoma, smoldering multiple myeloma, and newly diagnosed multiple myeloma.

Purpose: We performed a retrospective chart review on 393 patients with multiple myeloma (MM) to determine the utility of the gamma gap (GG)., Methods: We calculated the difference between a patient's total serum protein and albumin as a point-of-care test for assessing disease status in MM., Results: GG is highly correlated with the level of M-spike, and the change in GG correlates with myeloma treatment response. In addition, fitted linear models were established that allow for the calculation of M-protein level from the GG within hours from blood draw., Conclusion: Our study has important implications in the care of MM, particularly in countries/areas with limited resources.

We determined the impact of bone marrow fibrosis (BMF) on the clinical outcomes of newly diagnosed multiple myeloma (NDMM) patients in the current era of myeloma therapy. A total of 393 MM patients were included in the final analysis. The median followup was 83 months (range: 3.9 to 212 months). BMF was noted in 122 (48.2%) evaluable patients. Median progression free survival (PFS) in patients without BMF was 30.2 (95% CI: 24.7-38.0) months, and 21.1 (95% CI: 18.8-27.5) months in patients with BMF present (P = .024). Median overall survival (OS) was 61.2 (95% CI: 51.5-81.2) months in patients without BMF, and 45.1 (95% CI: 38.7-57.0) months in patients with BMF (P = .0048). A subset of 99 patients had their bone marrow biopsies stained for JAK1 and JAK2 by immunohistochemistry. Of these samples 67 (67.7%) patients had detectable JAK2 expression predominantly noted on bone marrow megakaryocytes. JAK2 expression correlated with myeloma disease stage (P = .0071). Our study represents the largest dataset to date examining the association of BMF with prognosis in the era of novel therapies and widespread use of hematopoietic stem cell transplant (HSCT). Our data suggest that MM patients with BMF (particularly those with extensive BMF) have a poorer prognosis even when treated with immunomodulatory agents and proteasome inhibitors., (© 2020 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

A cure for multiple myeloma (MM), a malignancy of plasma cells, remains elusive. Nearly all myeloma patients will eventually relapse and develop resistance to currently available treatments. There is an unmet medical need to develop novel and effective therapies that can induce sustained responses. Early phase clinical trials using chimeric antigen receptor (CAR) T cell therapy have shown great promise in the treatment of relapsed and/or refractory MM. In this review article, we provide an overview of the CAR constructs, the gene transfer vector systems, and approaches for T cell activation and expansion. We then summarize the outcomes of several early phase clinical trials of CAR T cell therapy in MM and the novel CAR T targets that are under development. Finally, we explore the potential mechanisms that result in disease relapse after CAR T therapy and propose future directions in CAR T therapy in MM., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The NCCN Guidelines for Multiple Myeloma provide recommendations for diagnosis, workup, treatment, follow-up, and supportive care for patients with monoclonal gammopathy of renal significance, solitary plasmacytoma, smoldering myeloma, and multiple myeloma. These NCCN Guidelines Insights highlight some of the important updates and changes in the 1.2020 version of the NCCN Guidelines for Multiple Myeloma.

The introduction of CD38-targeting monoclonal antibodies (CD38 MoABs), daratumumab and isatuximab, has significantly impacted the management of patients with multiple myeloma (MM). Outcomes of patients with MM refractory to CD38 MoABs have not been described. We analyzed outcomes of 275 MM patients at 14 academic centers with disease refractory to CD38 MoABs. Median interval between MM diagnosis and refractoriness to CD38 MoAB (T 0 ) was 50.1 months. The median overall survival (OS) from T 0 for the entire cohort was 8.6 [95% C.I. 7.5-9.9] months, ranging from 11.2 months for patients not simultaneously refractory to an immunomodulatory (IMiD) agent and a proteasome inhibitor (PI) to 5.6 months for "penta-refractory" patients (refractory to CD38 MoAB, 2 PIs and 2 IMiDs). At least one subsequent treatment regimen was employed after T 0 in 249 (90%) patients. Overall response rate to first regimen after T 0 was 31% with median progression-free survival (PFS) and OS of 3.4 and 9.3 months, respectively. PFS was best achieved with combinations of carfilzomib and alkylator (median 5.7 months), and daratumumab and IMiD (median 4.5 months). Patients with MM refractory to CD38 MoAB have poor prognosis and this study provides benchmark for new therapies to be tested in this population.

Multiple myeloma remains an incurable disease, and continued efforts are required to develop novel agents and novel drug combinations with more effective anti-myeloma activity. Here, we show that the pan-PIM kinase inhibitors SGI1776 and CX6258 exhibit significant anti-myeloma activity and that combining a pan-PIM kinase inhibitor with the immunomodulatory agent lenalidomide in an in vivo myeloma xenograft mouse model resulted in synergistic myeloma cell killing without additional hematologic or hepatic toxicities. Further investigations indicated that treatment with a pan-PIM kinase inhibitor promoted increased ubiquitination and subsequent degradation of IKZF1 and IKZF3, two transcription factors crucial for survival of myeloma cells. Combining a pan-PIM kinase inhibitor with lenalidomide led to more effective degradation of IKZF1 and IKZF3 in multiple myeloma cell lines as well as xenografts of myeloma tumors. We also demonstrated that treatment with a pan-PIM kinase inhibitor resulted in increased expression of cereblon, and that knockdown of cereblon via a shRNA lentivirus abolished the effects of PIM kinase inhibition on the degradation of IKZF1 and IKZF3 and myeloma cell apoptosis, demonstrating a central role of cereblon in pan-PIM kinase inhibitor-mediated down-regulation of IKZF1 and IKZF3 and myeloma cell killing. These data elucidate the mechanism of pan-PIM kinase inhibitor mediated anti-myeloma effect and the rationale for the synergy observed with lenalidomide co-treatment, and provide justification for a clinical trial of the combination of pan-PIM kinase inhibitors and lenalidomide for the treatment of multiple myeloma., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Despite significant improvements in the overall survival of patients with multiple myeloma (MM) over the past 15 years, the disease remains incurable. Treatment options are limited for patients who have relapsed or are refractory to immunomodulatory drugs (IMiDs), proteasome inhibitors, and monoclonal antibodies. In these patients, immunotherapies such as checkpoint inhibitors, oncolytic vaccines, and chimeric antigen receptor (CAR) T cells provide a potentially effective alternative treatment. While checkpoint inhibitors are effective in prolonging overall survival in some patients with advanced solid cancers and Hodgkin lymphoma, they have not demonstrated significant activity as a single agent in MM. In fact the combination of checkpoint inhibitors with IMiDs was recently found to increase the risk of death in myeloma patients. These challenges highlight the need for a better understanding of immune dysregulation in myeloma patients, and the mechanisms of action of- and resistance to- checkpoint inhibitors. In this review, we summarize immune dysfunction in patients with MM, and review the preclinical and clinical data regarding checkpoint inhibitors in myeloma. We conclude by proposing strategies to improve the efficacy and safety of checkpoint inhibitors in this population., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Although current chemotherapy using bortezomib (Velcade) against multiple myeloma in adults has achieved significant responses and even remission, a majority of patients will develop acquired resistance to bortezomib. Increased thioredoxin level has been reported to be associated with carcinogenesis; however, the role of thioredoxin in bortezomib drug resistance of myeloma remains unclear., Methods: We generated several bortezomib-resistant myeloma cell lines by serially passaging with increased concentrations of bortezomib over a period of 1.5 years. Thioredoxin expression was measured by real-time PCR and western blot., Results: The role of thioredoxin in the survival of bortezomib-resistant myeloma cells was determined by specific shRNA knockdown in vitro and in vivo. Thioredoxin inhibitor (PX12) was used to determine the effectiveness of thioredoxin inhibition in the treatment of bortezomib-resistant myeloma cells. The effect of thioredoxin inhibition on mitophagy induction was examined. The correlation of thioredoxin expression with patient overall survival was interrogated. Thioredoxin expression was significantly upregulated in bortezomib-resistant myeloma cells and the change correlated with the increase of bortezomib concentration. Thioredoxin gene knockdown using specific shRNA sensitized bortezomib-resistant myeloma cells to bortezomib efficiency in vitro and in vivo. Similarly, pharmacological inhibition with PX12 inhibited the growth of bortezomib-resistant myeloma cells and overcame bortezomib resistance in vitro and in vivo. Furthermore, inhibition of thioredoxin resulted in the activation of mitophagy and blockage of mitophagy prevented the effects of PX12 on bortezomib-resistant myeloma cells, indicating that mitophagy is the important molecular mechanism for the induction of cell death in bortezomib-resistant myeloma cells by PX12. Moreover, inhibition of thioredoxin resulted in downregulation of phosphorylated mTOR and ERK1/2. Finally, thioredoxin was overexpressed in primary myeloma cells isolated from bortezomib-resistant myeloma patients and overexpression of thioredoxin correlated with poor overall survival in patients with multiple myeloma., Conclusions: Our findings demonstrated that increased thioredoxin plays a critical role in bortezomib resistance in multiple myeloma through mitophagy inactivation and increased mTOR and ERK1/2 phosphorylation. Thioredoxin provides a potential target for clinical therapeutics against multiple myeloma, particularly for bortezomib-resistant/refractory myeloma patients.

The NCCN Guidelines for Multiple Myeloma provide recommendations for diagnosis, evaluation, treatment, including supportive-care, and follow-up for patients with myeloma. These NCCN Guidelines Insights highlight the important updates/changes specific to the myeloma therapy options in the 2018 version of the NCCN Guidelines., (Copyright © 2018 by the National Comprehensive Cancer Network.)

Objectives: Multiple myeloma (MM) primarily strikes older adults, but full-dose chemotherapy such as bortezomib (Velcade), cyclophosphamide and dexamethasone (VCD) is often excessively toxic to very old or frail adults and those with substantial comorbidities. We piloted dose-attenuated VCD ("VCD-Lite") in such vulnerable adults with newly diagnosed MM (NDMM)., Materials and Methods: Subjects with NDMM and a high risk of therapy-related toxicity due to factors above received bortezomib 1.3mg/m 2 subcutaneously, cyclophosphamide 300mg/m 2 and dexamethasone 40mg orally, all on days 1, 8, and 15 of a 28day cycle for eight cycles, followed by indefinite, alternating bortezomib and lenalidomide maintenance. Toxicity, overall response rate (ORR), progression-free and overall survival (PFS and OS) were determined. The Cancer and Aging Research Group geriatric assessment (CARG GA) was administered at baseline in an exploratory manner as a predictor of severe toxicity., Results: 14 patients went on the study, which was closed early due to slow accrual. Intention-to-treat ORR was 64%. 64% of patients experienced grade ≥3 adverse events, the majority of which were unlikely therapy-related. Median PFS was 24.2months and OS 29.7months, with 14%, 36% and 29% of patients discontinuing study drugs due to toxicity, MM progression and other reasons respectively. Baseline CARG GA was successfully completed by all subjects but one., Conclusion: VCD-Lite is a viable option for vulnerable adults with NDMM. CARG GA is feasible. Further studies to optimize therapy and to explore CARG GA as a toxicity predictor are vital., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Comprehensive recommendations for maintenance therapy after autologous stem cell transplantation (ASCT) for patients with multiple myeloma (MM) have yet to be defined. Bortezomib has been utilized as maintenance therapy after ASCT, but data attesting to the safety and efficacy of this agent compared with lenalidomide in the post-ASCT setting are limited. Therefore, we retrospectively analyzed the outcomes of 102 patients with MM who received maintenance therapy with bortezomib after ASCT at Duke University's adult bone marrow transplant clinic between 2005 and 2015. Maintenance with bortezomib was initiated between 60 and 90 days after ASCT as a single agent 1.3 mg/m 2 once every 2 weeks (n = 92) or in combination with lenalidomide (10 mg/day) (n = 10). The median age at ASCT was 64 (range, 31 to 78). Of the 99 patients with molecular data available, 42% had high-risk cytogenetics (including d17p, t(4;14), +1q, and t(14;16) by fluorescein in situ hybridization). Overall, 46% of patients experienced side effects from maintenance therapy, with 31% of all patients experiencing peripheral neuropathy. In total, 2% of patients required discontinuation of bortezomib maintenance because of adverse events. No secondary malignancies were reported from the therapy. The median progression-free survival (PFS) for patients receiving maintenance therapy with bortezomib after ASCT was 36.5 months (95% confidence interval [CI], 21.3 to not available) and median overall survival was 72.7 months (95% CI, 63.9 to not available). The PFS of patients with high-risk cytogenetics was not statistically significantly different from those with standard-risk cytogenetics, suggesting that maintenance with bortezomib may help overcome the impact of high-risk cytogenetics on early progression. These results indicate that maintenance therapy with bortezomib represents a safe, well-tolerated, and efficacious option for patients with high-risk cytogenetics, renal insufficiency, an inability to tolerate lenalidomide, or a previous history of another cancer., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Sphingolipid metabolism is being increasingly recognized as a key pathway in regulating cancer cell survival and proliferation. However, very little is known about its role in multiple myeloma (MM). We investigated the potential of targeting sphingosine kinase 2 (SK2) for the treatment of MM. We found that SK2 was overexpressed in MM cell lines and in primary human bone marrow (BM) CD1381 myeloma cells. Inhibition of SK2 by SK2- specific short hairpin RNA or ABC294640 (a SK2 specific inhibitor) effectively inhibited myeloma cell proliferation and induced caspase 3–mediated apoptosis. ABC294640 inhibited primary human CD1381 myeloma cells with the same efficacy as with MM cell lines. ABC294640 effectively induced apoptosis of myeloma cells, even in the presence of BM stromal cells. Furthermore, we found that ABC294640 downregulated the expression of pS6 and directed c-Myc and myeloid cell leukemia 1 (Mcl-1) for proteasome degradation. In addition, ABC294640 increased Noxa gene transcription and protein expression. ABC294640, per se, did not affect the expression of B-cell lymphoma 2 (Bcl-2), but acted synergistically with ABT-737 (a Bcl-2 inhibitor) in inducing myeloma cell death. ABC294640 suppressed myeloma tumor growth in vivo in mouse myeloma xenograft models. Our data demonstrated that SK2 provides a novel therapeutic target for the treatment of MM.This trial was registered at www.clinicaltrials.gov as #NCT01410981.

It is unknown whether clinical characteristics can successfully predict which multiple myeloma (MM) patients would be poor mobilizers with growth factor (GF) alone so they can be assigned to mobilization with chemotherapy + GF or GF + plerixafor. MM patients (N = 477) who underwent autologous mobilization with GF were retrospectively reviewed and assigned into training and validation cohorts. In multiple regression analysis, age, platelet count at time of mobilization, type of GF utilized, and extent of exposure to lenalidomide independently correlated with peripheral blood (PB)-CD34+ and were integrated in a predicting score (PS) for poor mobilizers, defined as PB-CD34+ < 20/mm(3) 4 days after initiation of GF. There was no correlation between institution, gender, time between diagnosis, and mobilization or plasma cells in the bone marrow at time of mobilization and PBCD34+. The PS cut-off found in the training cohort to have 90% sensitivity for prediction of poor mobilizers performed with 89.7% sensitivity but only 34.8% specificity in the validation cohort. Conversely, the PS cut-off developed to have 90% specificity performed with 86.9% specificity but only 37% sensitivity. We conclude that clinical characteristics identifiable before initiation of mobilization should not be used to stratify MM patients for different mobilization strategies., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Multiple myeloma (MM) is a debilitating disease of proliferating and malignant plasma cells that is currently incurable. The ability of monoclonal recurrence of disease suggests it might arise from a stem cell-like population capable of self-renewal. The difficulty to isolate the cancer stem-like cell in MM has introduced confusion toward this hypothesis. However, recent evidence has suggested that MM originates from the B cell lineage with memory-B cell like features, allowing for self-renewal of the progenitor-like status and differentiation to a monoclonal plasma cell population. Furthermore, this tumor-initiating cell uses signaling pathways and microenvironment similar to the hematopoietic stem cell, though hijacking these mechanisms to create and favor a more tumorigenic environment. The bone marrow niche allows for pertinent evasion, either through avoiding immunosurveillance or through direct interaction with the stroma, inducing quiescence and thus drug resistance. Understanding the interaction of the MM stem cell to the microenvironment and the mechanisms utilized by various stem cell-like populations to allow persistence and therapy-resistance can enable for better targeting of this cell population and potential eradication of the disease.

We utilized a cohort with a high frequency of young patients to explore the correlation between fluorescence in situ hybridization (FISH) detected chromosomal abnormalities (CA) and age in multiple myeloma (MM). One hundred and nineteen patients with MM were included in the analysis. The median age was 60 years, 51% of patients were female and 56% were Caucasian. Translocations involving the IGH gene on chromosome 14 were more likely to be detected in older (≥ 60 years) patients (32.8% vs. 15.5%, p = 0.03), particularly because of a higher frequency of t(4;14) (14.8% vs. 3.4%, p = 0.05). Myeloma cells from older patients were also three times more likely to have multiple CA. The presence of high-risk CA influenced survival in patients <60 but not in patients ≥ 60. Among standard-risk patients, survival was significantly superior for patients <60. No effect of age on survival was detected for high-risk patients.

Background: Plerixafor enhances the ability of filgrastim (FIL) to mobilize CD34+ cells but adds cost to the mobilization. We hypothesized that replacing weight-based FIL with flat-dose pegfilgrastim (PEG) in a validated cost-based mobilization algorithm for patient-adapted use of plerixafor would add convenience without increased cost., Study Design and Methods: A single-center retrospective analysis compared two consecutive cohorts undergoing FIL or PEG mobilization before autologous hematopoietic stem cell transplantation for multiple myeloma or lymphoma. FIL dose was 10 µg/kg/day continuing until completion of collection and a 12-mg flat dose of PEG. Peripheral blood CD34+ cells (PB-CD34+) enumeration was performed on the fourth day after initiation of growth factor. Subjects surpassing a certain target-specific threshold of PB-CD34+ started apheresis immediately while subjects with lower PB-CD34+ received plerixafor with apheresis starting on the fifth day., Results: Overall 68 of 74 in the FIL group and 52 of 57 patients in the PEG group met the mobilization target. Only one patient in each cohort required remobilization. Median PB-CD34+ on Day 4 was significantly higher in patients in the PEG group (18.1×10(6) vs. 28.7×10(6)cells/L, p=0.01). Consequently, patients in the PEG group were less likely to require administration of plerixafor (67.5% vs. 45.6%, p=0.01). Cohorts had near identical mean number of apheresis sessions and comparable CD34+ yield. The estimated cost associated with growth factor was higher in patients in the PEG group, but it was counterbalanced by lower cost associated with use of plerixafor., Conclusion: Single administration of 12 mg of PEG is associated with better CD34+ mobilization than FIL allowing for effective, convenient mobilization with less frequent use of plerixafor., (© 2012 American Association of Blood Banks.)

Simple Summary: Cereblon (CRBN) is a direct binding target of immunomodulatory drugs (IMiDs) that are commonly used to treat multiple myeloma (MM). Many patients with MM have comorbidities, including diabetes and/or dyslipidemia, and are treated with peroxisome proliferator-activated receptor (PPAR) agonists. This study aimed to further analyze the effects and mechanisms underlying the drug-to-drug interactions between IMiDs and PPAR agonists in MM. We found that PPAR agonists reduced CRBN expression by inducing DNA methylation and increasing protein degradation. PPAR agonists and IMiDs showed opposing metabolic effects in MM cells. Our retrospective study suggested an inferior response and outcome when PPARs and IMiDs were concurrently administered. Our study has important implications for the care of patients with MM and provides a foundation for exploring novel compounds or PPAR partial agonists/antagonists that can increase CRBN expression while retaining their lipid-lowering or insulin-sensitizing functions. Our previous study demonstrated that peroxisome proliferator-activated receptor (PPAR) agonists downregulated cereblon (CRBN) expression and reduced the anti-myeloma activity of lenalidomide in vitro and in vivo. We aimed to determine whether DNA methylation and protein degradation contribute to the effects of PPAR agonists. CRBN promoter methylation status was detected using methylation-specific polymerase chain reaction. The CRBN protein degradation rate was measured using a cycloheximide chase assay. Metabolomic analysis was performed in multiple myeloma (MM) cells treated with PPAR agonists and/or lenalidomide. Our retrospective study determined the effect of co-administration of PPAR agonists with immunomodulatory drugs on the outcomes of patients with MM. CpG islands of the CRBN promoter region became highly methylated upon treatment with PPAR agonists, whereas treatment with PPAR antagonists resulted in unmethylation. The CRBN protein was rapidly degraded after treatment with PPAR agonists. Lenalidomide and fenofibrate showed opposite effects on acylcarnitines and amino acids. Co-administration of immunomodulatory drugs and PPAR agonists was associated with inferior treatment responses and poor survival. Our study provides the first evidence that PPAR agonists reduce CRBN expression through various mechanisms including inducing methylation of CRBN promoter CpG island, enhancing CRBN protein degradation, and affecting metabolomics of MM cells. [ABSTRACT FROM AUTHOR]

Abstract Peripheral neuropathy (PN) is one of the most common side effects of bortezomib therapy. The majority of bortezomib-related PN is a sensory neuropathy of mild to moderate degree, and is reversible after dose reduction or discontinuation. However, occasionally bortezomib-induced neuropathy can be severe and affects motor and/or autonomic nerves, and may be mediated by immune process. The role of immune modulation therapy in the management of bortezomib-induced PN was not well established. Here, we reported a case of bortezomib-induced severe PN that responded well to plasma exchange and steroid treatment.

The roles of mitochondrial dysfunction in carcinogenesis remain largely unknown. The effects of PTEN‐induced putative kinase 1 (PINK1)‐dependent mitophagy on the pathogenesis of multiple myeloma (MM) are determined. The levels of the PINK1‐dependent mitophagy markers PINK1 and parkin RBR E3 ubiquitin protein ligase (PARK2) in CD138+ plasma cells are reduced in patients with MM and correlate with clinical outcomes in myeloma patients. Moreover, the induction of PINK1‐dependent mitophagy with carbonylcyanide‐m‐chlorophenylhydrazone (CCCP) or salinomycin, or overexpression of PINK1 leads to inhibition of transwell migration, suppression of myeloma cell homing to calvarium, and decreased osteolytic bone lesions. Furthermore, genetic deletion of pink1 accelerates myeloma development in a spontaneous X‐box binding protein‐1 spliced isoform (XBP‐1s) transgenic myeloma mouse model and in VK*MYC transplantable myeloma recipient mice. Additionally, treatment with salinomycin shows significant antimyeloma activities in vivo in murine myeloma xenograft models. Finally, the effects of PINK1‐dependent mitophagy on myeloma pathogenesis are driven by the activation of the Mps one binder kinase activator (MOB1B)‐mediated Hippo pathway and the subsequent downregulation of Yes‐associated protein (YAP)/transcriptional co‐activator with PDZ‐binding motif (TAZ) expression. These data provide direct evidence that PINK1‐dependent mitophagy plays a critical role in the pathogenesis of MM and is a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Abstract: Multiple myeloma (MM) remains an incurable disease in need of the development of novel therapeutic agents and drug combinations. ABT‐199 is a specific Bcl‐2 inhibitor in clinical trials for MM; however, its activity as a single agent was limited to myeloma patients with the t(11;14) translocation who acquire resistance due to co‐expression of Mcl‐1 and Bcl‐xL. These limitations preclude its use in a broader patient population. We have recently found that a sphingosine kinase 2‐specific inhibitor (ABC294640) induces apoptosis in primary human CD138+ cells and MM cell lines. ABC294640 is currently in phase I/II clinical trials for myeloma (clinicaltrials.gov: #NCT01410981). Interestingly, ABC294640 down‐regulates c‐Myc and Mcl‐1, but does not have any effects on Bcl‐2. We first evaluated the combinatorial anti‐myeloma effect of ABC294640 and ABT‐199 in vitro in 7 MM cell lines, all of which harbor no t(11;14) translocation. Combination index calculation demonstrated a synergistic anti‐myeloma effect of the combination of ABC294640 and ABT‐199. This synergistic anti‐myeloma effect was maintained even in the presence of bone marrow (BM) stromal cells. The combination of ABC294640 and ABT‐199 led to enhanced cleavage of PARP and caspase‐3/9 and increased Annexin‐V expression, consistent with the induction of apoptosis by the combination treatment. In addition, the combination of ABC294640 and ABT‐199 resulted in the down‐regulation of the anti‐apoptotic proteins Mcl‐1, Bcl‐2, and Bcl‐xL and the cleavage of Bax and Bid. The combination induced both the mitochondrial mediated‐ and caspase‐mediated apoptosis pathways. Finally, the combination of ABC294640 and ABT‐199 resulted in augmented anti‐myeloma effect in vivo in a mouse xenograft model. These findings demonstrate that the co‐administration of ABC294640 and ABT‐199 exhibits synergistic anti‐myeloma activity in vitro and in vivo, providing justification for a clinical study of this novel combination in patients with relapsed/refractory multiple myeloma. [ABSTRACT FROM AUTHOR]

Simple Summary: Multiple myeloma is the second most common hematologic malignancy in the United States. Eventually, all myeloma patients will relapse and develop resistance to currently available agents. There is an unmet medical need to identify novel therapeutic targets. PIM kinases play an important role in myeloma pathogenesis and disease relapse. We herein provided a comprehensive review on the roles of PIM kinases in myeloma cell survival and proliferation and in the bone marrow microenvironment that supports myeloma growth. The development and testing of novel PIM kinase inhibitors were summarized. Finally, the preclinical studies of the combinatorial effects of PIM kinase inhibitors and other anti-myeloma agents were presented. Multiple myeloma (MM) remains an incurable disease and novel therapeutic agents/approaches are urgently needed. The PIM (Proviral insertion in murine malignancies) serine/threonine kinases have 3 isoforms: PIM1, PIM2, and PIM3. PIM kinases are engaged with an expansive scope of biological activities including cell growth, apoptosis, drug resistance, and immune response. An assortment of molecules and pathways that are critical to myeloma tumorigenesis has been recognized as the downstream targets of PIM kinases. The inhibition of PIM kinases has become an emerging scientific interest for the treatment of multiple myeloma and several PIM kinase inhibitors, such as SGI-1776, AZD1208, and PIM447 (formerly LGH447), have been developed and are under different phases of clinical trials. Current research has been focused on the development of a new generation of potent PIM kinase inhibitors with appropriate pharmacological profiles reasonable for human malignancy treatment. Combination therapy of PIM kinase inhibitors with chemotherapeutic appears to create an additive cytotoxic impact in cancer cells. Notwithstanding, the mechanisms by which PIM kinases modulate the immune microenvironment and synergize with the immunomodulatory agents such as lenalidomide have not been deliberately depicted. This review provides a comprehensive overview of the PIM kinase pathways and the current research status of the development of PIM kinase inhibitors for the treatment of MM. Additionally, the combinatorial effects of the PIM kinase inhibitors with other targeted agents and the promising strategies to exploit PIM as a therapeutic target in malignancy are highlighted. [ABSTRACT FROM AUTHOR]