Once weekly selinexor, carfilzomib and dexamethasone in carfilzomib non-refractory multiple myeloma patients

Treatment of Multiple Myeloma in Patients Refractory to Daratumumab/Anti-CD38 Monoclonal Antibodies: A Systematic Review

BACKGROUND

There is a lack of clear guidance on the appropriate next choice of therapy for patients with relapsed/refractory multiple myeloma who become refractory to daratumumab, an anti-CD38 antibody. This review aims to identify and compare treatments with published clinical trial evidence among patients with daratumumab-refractory multiple myeloma.

METHODS

MEDLINE, Cochrane CENTRAL, and EMBASE databases were searched for clinical trials that evaluated treatments for patients with multiple myeloma who were refractory to daratumumab from November 2015 to October 2023. Eligible studies may have enrolled only patients who were refractory to daratumumab or reported findings on patients with daratumumab-refractory disease in subgroup analyses. Treatment outcomes of interest included response rates and survival outcomes. Screening and data extraction were done independently by two reviewers using covidence, and any discrepancy was resolved by a third reviewer. Qualitative synthesis was performed to describe and compare patient outcomes associated with different treatments.

RESULTS

A total of 33 papers/published studies, representing 23 clinical trials, were eligible/included. Interventions from the eligible trials include chimeric antigen receptor (CAR)-T cell therapy, B-cell maturation antigen (BCMA)-directed antibodies, other monoclonal antibodies, cereblon E3 ligase modulators, a peptide-drug conjugate, and other targeted therapies. CAR T-cell therapy demonstrated the highest overall response rates, longer median overall, and progression-free survival in addition to significantly lower risk of death and higher odds of response compared to standard of care. Similarly, high response rates and/or long-term survival was also observed for other BCMA-directed treatments, such as elranatamab and teclistamab.

CONCLUSION

Based on the results of this systematic review, BCMA-directed therapies such as CAR-T cell therapy and bispecific antibodies demonstrate promising efficacy among patients with anti-CD38 refractory disease. However, additional evidence from randomized clinical trials is necessary to establish best practice guidelines.

International myeloma working group immunotherapy committee recommendation on sequencing immunotherapy for treatment of multiple myeloma

T-cell redirecting therapy (TCRT), specifically chimeric antigen receptor T-cell therapy (CAR T-cells) and bispecific T-cell engagers (TCEs) represent a remarkable advance in the treatment of multiple myeloma (MM). There are several products available around the world and several more in development targeting primarily B-cell maturation antigen (BCMA) and G protein-coupled receptor class C group 5 member D (GRPC5D). The relatively rapid availability of multiple immunotherapies brings the necessity to understand how a certain agent may affect the safety and efficacy of a subsequent immunotherapy so MM physicians and patients can aim at optimal sequential use of these therapies. The International Myeloma Working Group conveyed panel of experts to review patient and disease-related factors affecting efficacy and safety of immunotherapy, summarize existing information on sequencing therapy and provide a series of core recommendations.

Safety assessment of selinexor: a real-world pharmacovigilance study

BACKGROUND

Selinexor is approved for the treatment of relapsed or refractory multiple myeloma. However, a comprehensive understanding of adverse events associated with selinexor is lacking.

METHODS

Clinical trials of selinexor in patients with multiple myeloma were reviewed. We investigated selinexor-related adverse events through data of the US Food and Drug Administration Adverse Event Reporting System (FAERS). The disproportionality analysis was conducted. Four algorithms were employed to evaluate the signals of adverse events. The adverse effects of selinexor combined with dexamethasone were compared with bortezomib and dexamethasone. Sensitivity analysis was performed to exclude consumer-reported adverse events. The onset of adverse reactions were calculated.

RESULTS

A total of 1,698 reports related with selinexor from FAERS were identified. 6 significant system organ class and 42 significant preferred terms (PTs) were found. Unexpected significant adverse events including mania, acute kidney injury, orthostatic hypotension, and embolisms were identified. 14 PTs reported significant signals in treatment of selinexor combined dexamethasone compared with traditional treatment of bortezomib and dexamethasone. 45.2% of adverse events occurred within the first month of starting selinexor.

CONCLUSIONS

Comprehensive analyses of selinexor related adverse events are helpful for clinical detection of adverse events and timely intervention, advancing selinexor's therapeutic progress in future treatment.

Novel-and Not So Novel-Inhibitors of the Multifunctional CRM1 Protein

Chromosome Region Maintenance 1 (CRM1), also known as Exportin 1 (XPO1), is a protein that is critical for transport of proteins and RNA to the cytoplasm through the nuclear pore complex. CRM1 inhibition with small molecule inhibitors is currently being studied in many cancers, including leukemias, solid organ malignancies and brain tumors. We review the structure of CRM1, its role in nuclear export, the current availability of CRM1 inhibitors, and the role of CRM1 in a number of distinct cellular processes. A deeper understanding of how CRM1 functions in nuclear export as well as other cellular processes may allow for the development of additional novel CRM1 inhibitors.

Unraveling the complexity of drug resistance mechanisms to SINE, T cell-engaging therapies and CELMoDs in multiple myeloma: a comprehensive review

Despite significant advances in the understanding of multiple myeloma (MM) biology and the development of novel treatment strategies in the last two decades, MM is still an incurable disease. Novel drugs with alternative mechanisms of action, such as selective inhibitors of nuclear export (SINE), modulators of the ubiquitin pathway [cereblon E3 ligase modulatory drugs (CELMoDs)], and T cell redirecting (TCR) therapy, have led to significant improvement in patient outcomes. However, resistance still emerges, posing a major problem for the treatment of myeloma patients. This review summarizes current data on treatment with SINE, TCR therapy, and CELMoDs and explores their mechanism of resistance. Understanding these resistance mechanisms is critical for developing strategies to overcome treatment failure and improve therapeutic outcomes.

Efficacy and safety of selinexor for patients with relapsed and refractory multiple myeloma: A meta-analysis

PURPOSE

Selinexor is a first-in-class, oral selective-inhibitor-of-nuclear-export, granted accelerated approval by FDA (2019) for relapsed and refractory multiple myeloma (RRMM). We sought to quantitatively summarize the selinexor efficacy and safety in RRMM.

METHODS

We searched PubMed, EMBASE, CENTRAL, clinicaltrial.gov, and google scholar, until May 2023, studies about selinexor use in RRMM. The outcome measures of interest were primarily efficacy outcomes, in addition to safety outcomes. Random-effect model analyses were performed, at statistical significance of P<0.05, using the RevMan software.

RESULTS

Meta-analyses of eleven included clinical trials yielded a significant 56.21% overall clinical benefit, 46.91% overall response, 4.89% complete response, 23.41% very good partial response, 24.68% partial response, and 28.06% stable disease rates with selinexor. Due to safety reasons, selinexor caused significant increase in discontinuation rate, 16.80%. Subgroup analyses demonstrated higher efficacy with selinexor plus dexamethasone and proteasome inhibitor combinations than with selinexor alone. The multiple myeloma type, high cytogenetic risk, refractory state, and advanced disease state did not affect performance. Risk of selection, performance, and detection biases were unclear in the included trials.

CONCLUSION

Selinexor led to significant positive responses with an acceptable safety profile in RRMM patients, despite higher rates of safety-related discontinuations. Selinexor-based combinations further enhanced response.

The numerous facets of 1q21+ in multiple myeloma: Pathogenesis, clinicopathological features, prognosis and clinical progress (Review)

Multiple myeloma (MM) is a malignant neoplasm characterized by the clonal proliferation of abnormal plasma cells (PCs) in the bone marrow and recurrent cytogenetic abnormalities. The incidence of MM worldwide is on the rise. 1q21+ has been found in ~30-40% of newly diagnosed MM (NDMM) patients.1q21+ is associated with the pathophysiological mechanisms of disease progression and drug resistance in MM. In the present review, the pathogenesis and clinicopathological features of MM patients with 1q21+ were studied, the key data of 1q21+ on the prognosis of MM patients were summarized, and the clinical treatment significance of MM patients with 1q21+ was clarified, in order to provide reference for clinicians to develop treatment strategies targeting 1q21+.

Efficacy and safety of once weekly selinexor 40 mg versus 60 mg with pomalidomide and dexamethasone in relapsed and/or refractory multiple myeloma

Objective

To identify the optimal dose of selinexor in combination with pomalidomide and dexamethasone (SPd).

Methods

An analysis of efficacy and safety of 2 once-weekly selinexor regimens (60 mg and 40 mg) with pomalidomide and dexamethasone (SPd-60 and SPd-40, respectively) given to patients with relapsed/refractory multiple myeloma (RRMM) in the STOMP (NCT02343042) and XPORT-MM-028 (NCT04414475) trials.

Results

Twenty-eight patients (60.7% males, median age 67.5 years) and 20 patients (35.0% males, median age 65.5 years) were analyzed in the SPd-40 and SPd-60 cohorts, respectively. Overall response rate was 50% (95% confidence interval [CI] 30.6-69.4%) and 65% (95% CI 40.8-84.6%), respectively. Very good partial response or better was reported in 28.6% (95% CI 13.2-48.7%) and 30.0% (95% CI 11.9-54.3%) of patients, respectively. Among 27 responders in both cohorts, the 12-month sustained response rate was 83.3% (95% CI 64.7-100.0%) for SPd-40 and 28.1% (95% CI 8.9-88.8%) for SPd-60. Median progression-free survival was 18.4 months (95% CI 6.5 months, not evaluable [NE]) and 9.5 months (95% CI 7.6 months-NE) for SPd-40 and SPd-60, respectively. Twenty-four-month survival rates were 64.2% (95% CI 47.7-86.3%) for SPd-40 and 51.1% (95% CI 29.9-87.5%) for SPd-60. Treatment-emergent adverse events (TEAEs) included neutropenia (all grades: SPd-40 64.3% versus SPd-60 75.0%), anemia (46.4% versus 65.0%), thrombocytopenia (42.9% versus 45.0%), fatigue (46.4% versus 75.0%), nausea (32.1% versus 70.0%) and diarrhea (28.6% versus 35.0%).

Conclusion

The all-oral combination of SPd exhibited preliminary signs of efficacy and was generally tolerable in patients with RRMM. The overall risk-benefit profile favored the SPd-40 regimen.

Case report: Light-chain amyloidosis responsive to selinexor in combination with daratumumab and dexamethasone (SDd) therapy

The outcome of AL amyloidosis remains poor, particularly in patients with advanced organ involvement which takes long time to recovery. We conducted an observational study of two patients with AL amyloidosis treated with SDd regimen. Both patients successfully achieved significant hematological and organ responses without severe adverse events, and the time to organ response was remarkably shorter than previously reported. Notably, an over 15% reduction in interventricular septal thickness (IVST) was observed in patient#2 within 6 months. Up to now, SDd therapy has not been previously reported in AL amyloidosis and may be a promising option for these patients.

Selinexor for the treatment of patients with relapsed or refractory multiple myeloma

OBJECTIVE

Multiple myeloma cells resist standard therapies due to overexpression of the transport protein, exportin 1. Selinexor is a novel drug that targets the Exportin 1 protein in these cells.

DATA SOURCE

A comprehensive search was done, and data showing the efficacy and safety of selinexor in relapsed/refractory multiple myeloma was collected using PubMed, Google Scholar, and clincialtrials.gov.

DATA SUMMARY

Results from the clinical trials STORM, BOSTON, and STOMP were included. Parts I and II of the STORM trial revealed a progression-free survival (PFS) of 4.7 and 3.7 months, a median duration of response of 6.2 and 4.4 months, and an overall survival of 7.3 and 8.4 months, respectively. BOSTON trial's SVd arm (selinexor, bortezomib, and dexamethasone) had a median follow-up period of 13.2 months and an mPFS of 13.93 months. The Vd arm (bortezomib and dexamethasone) had a median follow-up duration of 16.5 months and an mPFS of 9.46 months. The STOMP trial is still active and has limited data available. The SKd arm (selinexor, carfilzomib, and dexamethasone) reported an overall response rate of 66.7% in patients with triple refractory multiple myeloma, and 82% in patients with high-risk cytogenetics. The SPd arm (selinexor, pomalidomide, and dexamethasone) shows an overall response rate of 54.30% in pomalidomide naïve-nonrefractory, 35.70% in pomalidomide refractory and 60% in those dosed at RP2D. SRd arm (selinexor, lenalidomide, and dexamethasone) shows an overall response rate of 91.7% in lenalidomide naïve and 12.5% in lenalidomide refractory patients. SVd (selinexor, bortezomib, and dexamethasone) arm reported an overall response rate of 63% in all patients while the SDd arm (selinexor, daratumumab, and dexamethasone) showed an overall response rate of 73%.

CONCLUSION

To improve the outcome of patients with relapsed/refractory multiple myeloma, it is critical to develop new therapies, assess potential therapeutic synergies, and overcome drug resistance by determining the efficacy of multiple myeloma therapies across multiple disease subgroups.

Selinexor in multiple myeloma

INTRODUCTION

Selinexor, an XPO1 inhibitor, has emerged as a promising therapeutic option in the challenging landscape of relapsed/refractory multiple myeloma (RRMM).

AREAS COVERED

This article provides a review of selinexor, with a focus on available clinical studies involving MM patients and its safety profile. Clinical trials, such as STORM and BOSTON, have demonstrated its efficacy, particularly in combination regimens, showcasing notable overall response rates (ORR) and prolonged median progressionfree survival (mPFS). Selinexor's versatility is evident across various combinations, including carfilzomibdexamethasone (XKd), lenalidomidedexamethasone (XRd), and pomalidomidedexamethasone (XPd), with efficacy observed even in tripleclass refractory and highrisk patient populations. However, challenges, including resistance mechanisms and adverse events, necessitate careful management. Realworld evidence also underscores selinexor's effectiveness in RRMM, though dose adjustments and supportive measures remain crucial. Ongoing trials are exploring selinexor in diverse combinations and settings, including pomalidomidenaïve patients and postautologous stem cell transplant (ASCT) maintenance.

EXPERT OPINION

The evolving landscape of selinexor's role in the sequencing of treatment for RRMM, its potential in highrisk patients, including those with extramedullary disease, as revealed in the most recent international meetings, and ongoing investigations signal a dynamic era in myeloma therapeutics. Selinexor emerges as a pivotal component in multidrug strategies and innovative combinations.

Treatment of multiple myeloma with selinexor: a review

Over the last 20 years, breakthroughs in accessible therapies for the treatment of multiple myeloma (MM) have been made. Nevertheless, patients with MM resistant to immunomodulatory drugs, proteasome inhibitors, and anti-CD38 monoclonal antibodies have a very poor outcome. Therefore, it is necessary to explore new drugs for the treatment of MM. This review summarizes the mechanism of action of selinexor, relevant primary clinical trials, and recent developments in both patients with relapsed/refractory myeloma and patients with newly diagnosed myeloma. Selinexor may be useful for the treatment of refractory MM.

Advances in research on potential inhibitors of multiple myeloma

Multiple myeloma (MM) is a common hematological malignancy. Although recent clinical applications of immunomodulatory drugs, proteasome inhibitors and CD38-targeting antibodies have significantly improved the outcome of MM patient with increased survival, the incidence of drug resistance and severe treatment-related complications is gradually on the rise. This review article summarizes the characteristics and clinical investigations of several MM drugs in clinical trials, including their structures, mechanisms of action, structure-activity relationships, and clinical study progress. Furthermore, the application potentials of the drugs that have not yet entered clinical trials are also reviewed. The review also outlines the future directions of MM drug development.

Neural stem cell-derived exosomes-loaded adhesive hydrogel controlled-release promotes cerebral angiogenesis and neurological function in ischemic stroke

OBJECTIVE

Ischemic stroke has become one of the leading diseases for international death, which brings burden to the economy and society. Exosomes (Exos) derived following neural stem cells (NSCs) stimulation promote neurogenesis and migration of NSCs. However, Exos themselves are easily to be removed in vivo. Our study is to investigate whether adhesive hyaluronic acid (HAD) hydrogel loading NSCs-derived-Exo (HAD-Exo) would promote the recovery of ischemic stroke.

METHODS

A mouse model of middle cerebral artery occlusion (MCAO) was established. PBS, Exo, HAD, and HAD-Exo groups were independently stereotactically injected in mice, respectively. The modified neurological severity score scale and behaviour tests were used to evaluate neurological improvement. Neuroimagings were used to observe the improvement of cerebral infarct volume and vessels. Immunofluorescence staining was used to verify the expression of vascular and cell proliferation-related proteins.

RESULTS

The structural and mechanical property of HAD and HAD-Exo were detected. Behavioral results showed that HAD-Exo significantly improved neurological functions, especially motor function. Neuroimagings showed that HAD-Exo significantly promoted infarct volume and angiogenesis. Immunofluorescence staining showed that HAD-Exo significantly promoted the cerebral angiogenesis and anti-inflammation.

CONCLUSION

NSCs derived exosomes-loaded adhesive HAD hydrogel controlled-release could promote cerebral angiogenesis and neurological function for ischemic stroke.

Association of Selinexor Dose Reductions With Clinical Outcomes in the BOSTON Study

BACKGROUND

Dose modifications in response to adverse events (AEs) can maintain tumor response and improve therapy tolerability. We conducted a post-hoc analysis of the efficacy and safety of reduced selinexor doses in the BOSTON trial (NCT03110562).

PATIENTS AND METHODS

Efficacy, safety, and quality of life (QoL) in 195 patients with relapsed/refractory multiple myeloma randomized to once-weekly (QW) selinexor (100 mg), QW subcutaneous bortezomib (1.3 mg/m2), and twice-weekly dexamethasone (20 mg) were compared between patients with dose reductions and those without.

RESULTS

In total, 126 patients (65%) had selinexor dose reductions (median dose 71.4 mg/wk). In patients with dose reductions versus those without median progression-free survival was 16.6 months (95% CI 12.9-not evaluable [NE]) versus 9.2 months [95% CI 6.8-15.5]), overall response rate was 81.7% (95% CI 73.9-88.1%) versus 66.7% (95% CI 54.3-77.6%), ≥very good partial response was (51.6% [95% CI 42.5-60.6%] vs. 31.9% [95% CI 21.2-44.2]), median duration of response was not reached (95% CI 13.8-NE) versus 12.0 months (95% CI 8.3-NE), and time to next treatment was 22.6 months (95% CI 14.6-NE) versus 10.5 months (95% CI 6.3-18.2). Mean best change from baseline on the EORTC QLQ-C30 Global Health Status/QoL scale was 10.0 ± 20.5 versus 4.0 ± 20.9. Duration-adjusted AE rates that were lower after selinexor dose reduction included thrombocytopenia (62.5% before vs. 47.6% after), nausea (31.6% vs. 7.3%), fatigue (28.1% vs. 9.9%), decreased appetite (21.5% vs. 6.4%), anemia (17.9% vs. 10.3%), and diarrhea (12.9% vs. 5.2%).

CONCLUSION

Appropriate dose reductions in response to AEs of the 100 mg selinexor starting dose in the BOSTON study were associated with improved efficacy, reduced AE rates and improved QoL.

Real World Efficacy and Toxicity of Selinexor: Importance of Patient Characteristics, Dose Intensity and Post Progression Outcomes

BACKGOUND

Selinexor is an orally available selective inhibitor of exportin-1 that has offered a new treatment option in relapsed or refractory myeloma (RRMM) either in combination with dexamethasone (Sd) or with bortezomib and dexamethasone (SVd).

PATIENTS-METHODS

We evaluated the efficacy and toxicity of selinexor combinations in the real world, post progression therapies and their outcomes. The analysis included 44 patients with RRMM treated with Sd (N = 21, 48%) or SVd (N = 23, 52%).

RESULTS

On intent-to-treat, response rate (ORR) among all treated patients was 29.5% (13/44, of which CR: 2, VGPR: 3, PR:8); ORR was 35% for SVd and 24% for Sd. Median PFS was 3.0 months for all; 6.9 months for responders (≥PR),2.7 months for Sd and 3.4 months for SVd treated patients. In univariate analysis, serum albumin <3.5 g/dl and LDH >ULN were associated with worse PFS (P = .001 and P = .032, respectively).The OS of the whole cohort exceeded one year while serum albumin <3.5 gr/dl and LDH>ULN were associated with worse OS. After progression to Sd/SVd, 20 patients received further therapy; on ITT, the ORR was 40% (8/20) and the subsequent PFS was 3.4 months. The most common adverse events were fatigue, thrombocytopenia and nausea, while the most recorded grade 3 or 4 side effect was thrombocytopenia; 56% (25/44) of patients required dose reduction, however, this was not associated with inferior PFS.

CONCLUSION

In conclusion, selinexor-based therapy provides an additional treatment option in the real word setting and with appropriate dosing and toxicity management a subset of patients may have significant benefit.

Impacting T-cell fitness in multiple myeloma: potential roles for selinexor and XPO1 inhibitors

Competent T-cells with sufficient levels of fitness combat cancer formation and progression. In multiple myeloma (MM), T-cell exhaustion is caused by several factors including tumor burden, constant immune activation due to chronic disease, age, nutritional status, and certain MM treatments such as alkylating agents and proteasome inhibitors. Many currently used therapies, including bispecific T-cell engagers, anti-CD38 antibodies, proteasome inhibitors, and CART-cells, directly or indirectly depend on the anti-cancer activity of T-cells. Reduced T-cell fitness not only diminishes immune defenses, increasing patient susceptibility to opportunistic infections, but can impact effectiveness MM therapy effectiveness, bringing into focus sequencing strategies that could modulate T-cell fitness and potentially optimize overall benefit and clinical outcomes. Certain targeted agents used to treat MM, such as selective inhibitors of nuclear export (SINE) compounds, have the potential to mitigate T-cell exhaustion. Herein referred to as XPO1 inhibitors, SINE compounds inhibit the nuclear export protein exportin 1 (XPO1), which leads to nuclear retention and activation of tumor suppressor proteins and downregulation of oncoprotein expression. The XPO1 inhibitors selinexor and eltanexor reduced T-cell exhaustion in cell lines and animal models, suggesting their potential role in revitalizating these key effector cells. Additional clinical studies are needed to understand how T-cell fitness is impacted by diseases and therapeutic factors in MM, to potentially facilitate the optimal use of available treatments that depend on, and impact, T-cell function. This review summarizes the importance of T-cell fitness and the potential to optimize treatment using T-cell engaging therapies with a focus on XPO1 inhibitors.

Selinexor-Based Triplet Regimens in Patients With Multiple Myeloma Previously Treated With Anti-CD38 Monoclonal Antibodies

BACKGROUND

The increasing use of anti-CD38 monoclonal antibodies (αCD38 mAbs) for newly diagnosed or early relapsed multiple myeloma (MM), especially in non-transplant eligible patients, may lead to more patients developing αCD38 mAb-refractory disease earlier in the treatment course with fewer treatment options.

PATIENTS AND METHODS

We analyzed the efficacy and safety of selinexor-based triplets (selinexor+dexamethasone [Sd] plus pomalidomide [SPd, n = 23], bortezomib [SVd, n = 16] or carfilzomib (SKd, n = 23]) in a subset of STOMP (NCT02343042) and BOSTON (NCT03110562) study patients treated previously with αCD38 mAbs.

RESULTS

Sixty-two patients (median 4 prior therapies, range 1 to 11, 90.3% refractory to αCD38 mAb) were included. Overall response rates (ORR) in the SPd, SVd and SKd cohorts were 52.2%, 56.3%, and 65.2%, respectively. Overall response rate was 47.4% among patients who had MM refractory to the third drug reintroduced in the Sd-based triplet. Median progression-free survival in the SPd, SVd, and SKd cohorts was 8.7, 6.7, and 15.0 months, respectively, and median overall survival was 9.6, 16.9, and 33.0 months, respectively. Median time to discontinuation in the SPd, SVd, and SKd cohorts was 4.4, 5.9, and 10.6 months, respectively. The most common hematological adverse events were thrombocytopenia, anemia, and neutropenia. Nausea, fatigue, and diarrhea were primarily grade 1/2. Adverse events were generally manageable with standard supportive care and dose modifications.

CONCLUSION

Selinexor-based regimens may offer effective and well-tolerated therapy to patients with relapsed and/or refractory MM who had disease previously exposed or refractory to αCD38 mAb therapy and could help address the unmet clinical need in these high-risk patients.

A phase I study of selinexor combined with weekly carfilzomib and dexamethasone in relapsed/refractory multiple myeloma

We performed a phase I study of weekly selinexor, carfilzomib, and dexamethasone (wSKd) in patients with relapsed/refractory multiple myeloma (MM). The primary objective was to identify the maximum tolerated dose (MTD) of wSKd. Secondary endpoints included overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Prior exposure/refractoriness to carfilzomib was permitted. Thirty patients were enrolled; 26 (87%) had triple-class exposed disease and 6 (20%) received chimeric antigen receptor (CAR) T-cell therapy. Dose level 2 (carfilzomib 70 mg/m² Intravenous [IV] on Days 1, 8, and 15; selinexor 100 mg PO on Days 1, 8, 15, 22; dexamethasone 40 mg on Days 1, 8, 15, 22 of 28-day cycles) was chosen as the MTD, with no DLTs having occurred. The most common hematologic adverse events (AE) were thrombocytopenia (83%), anemia (70%), lymphopenia (50%), and neutropenia (50%). The most common nonhematologic AE were fatigue (70%), nausea (70%), diarrhea (53%), and anorexia (47%). The ORR was 21/30 (70%) overall and 18/23 (78%) at the MTD. At a median follow-up of 12.3 months, the median PFS was 5.3 months and median OS 23.3 months. Responses were similar in carfilzomib naïve and exposed patients. Long-term efficacy of wSKd is modest; wSKd could be employed as a bridging strategy to immunotherapies.

Selinexor-based regimens in patients with multiple myeloma after prior anti-B-cell maturation antigen treatment

There is a lack of consensus on therapy sequencing in previously treated multiple myeloma, particularly after anti-B-cell maturation antigen (BCMA) therapy. Earlier reports on selinexor (X) regimens demonstrated considerable efficacy in early treatment, and after anti-BCMA-targeted chimeric antigen receptor-T cell therapy. Here, we present data from 11 heavily pretreated patients who predominantly received BCMA-antibody-drug conjugate therapy. We observe that X-containing regimens are potent and achieve durable responses with numerically higher overall response and clinical benefit rates, as well as median progression free survival compared to patients' prior anti-BCMA therapies, despite being used later in the treatment course. In an area of evolving unmet need, these data reaffirm the efficacy of X-based regimens following broader anti-BCMA therapy.

Selinexor therapy for multiple myeloma and non-Hodgkin lymphomas

PURPOSE OF REVIEW

In this review we highlight the most recent studies furthering the clinical development of selinexor, a novel exportin-1 inhibitor, for the treatment of multiple myeloma and non-Hodgkin lymphomas.

RECENT FINDINGS

Three pivotal trials, the SADAL trial for diffuse large B-cell lymphoma, and the BOSTON and selinexor treatment of refractory myeloma trials for multiple myeloma, have recently led to the regulatory approval of selinexor monotherapy or combination regimens. They are complemented by several earlier phase clinical trials with iterative combinations, adding selinexor to novel therapies and cytotoxic chemotherapy regimens at various stages in the disease courses. In some, selinexor appears synergistic, occasionally overcoming treatment refractoriness, whereas in other situations appears additive. Consistent issues with tolerability are seen across trials, although consensus guidelines on their preemption and management have recently been adopted which may improve treatment success. While comparative data are lacking, the efficacy of selinexor-based regimens does not approach that of contemporaneous cellular and immunotherapies.

SUMMARY

Selinexor is a novel and potentially synergistic therapy for lymphoid malignancies, although requires refined supportive measures and strategies to improve its efficacy. Likely, for continued success, it will need to identify niches that complement recent advances, such as bridging to cellular therapies or maintenance thereafter.

Toxicity management strategies for next-generation novel therapeutics in multiple myeloma

The therapeutic options available for patients with multiple myeloma have greatly expanded over the past decade and incorporating these novel agents into routine clinical practice has significantly improved outcomes. The next generation of therapeutics is available for relapsed and refractory patients either as standard of care or in clinical trial, and these drugs represent a generational paradigm shift. Patients now have access to a multitude of novel immunotherapeutics, including monoclonal antibodies, an antibody-drug conjugate, chimeric antigen receptor T-cells (CAR-T), and bispecific T-cell redirecting antibodies, and novel oral therapies including selinexor (selective inhibitor of nuclear export) and venetoclax (bcl-2 inhibitor). While these drugs have the potential to be highly efficacious in certain subsets of patients when used as single agents or in combination regimens, they are each associated with unique toxicity profiles. It is imperative to understand these potential adverse events to ensure patient safety. Appropriate supportive care management is paramount to maximize drug exposure and therapeutic efficacy. The following review focuses its discussion on drugs and combination regimens that are currently FDA-approved and those that continue to be investigated in clinical trials, highlights the clinically relevant toxicity profiles for each of the different agents, and provides practical considerations for the treatment team.

Hypermethylation of the Promoter Region of miR-23 Enhances the Metastasis and Proliferation of Multiple Myeloma Cells via the Aberrant Expression of uPA

Multiple myeloma has a long course, with no obvious symptoms in the early stages. However, advanced stages are characterized by injury to the bone system and represent a severe threat to human health. The results of the present work indicate that the hypermethylation of miR-23 promoter mediates the aberrant expression of uPA/PLAU (urokinase plasminogen activator, uPA) in multiple myeloma cells. miR-23, a microRNA that potentially targets uPA’s 3’UTR, was predicted by the online tool miRDB. The endogenous expressions of uPA and miR-23 are related to disease severity in human patients, and the expression of miR-23 is negatively related to uPA expression. The hypermethylation of the promoter region of miR-23 is a promising mechanism to explain the low level of miR-23 or aberrant uPA expression associated with disease severity. Overexpression of miR-23 inhibited the expression of uPA by targeting the 3’UTR of uPA, not only in MM cell lines, but also in patient-derived cell lines. Overexpression of miR-23 also inhibited in vitro and in vivo invasion of MM cells in a nude mouse model. The results therefore extend our knowledge about uPA in MM and may assist in the development of more effective therapeutic strategies for MM treatment.

How I treat triple-class refractory multiple myeloma

Immunomodulatory imide drugs (IMiDs), proteasome inhibitors (PIs) and anti-CD38 monoclonal antibodies (MoAbs) are the pillars of modern multiple myeloma (MM) therapy. The prognosis of patients with MM that became refractory to these three classes (triple-class refractory [TCR]) is historically poor. Observational studies indicate an overall response rate of ~30% and overall survival inferior to 1 year with existing therapies. While no randomised trial has been completed in this setting, several agents exploring new mechanisms of action showed activity in TCR MM in single-arm trials, including anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T cells, anti-BCMA antibody-drug conjugates and exportin 1 (XPO1) inhibitors. Among agents in development, anti-BCMA bispecific T-cell engagers (TCE), and non-BCMA TCEs demonstrated activity in most patients. Additionally, specific agents may exhibit unique activity in biologically defined patient subsets, as exemplified by venetoclax in t(11;14) MM. The main open questions in TCR MM are preferred sequence of existing therapies, the utility of sequential use of agents with similar mechanism of action, but different immunotherapy target and the relative efficacy of the different anti-BCMA platforms. Here, we summarise the existing literature and provide general guidance on selecting therapy for this challenging and heterogenous group of patients.

Once weekly selinexor, carfilzomib and dexamethasone in carfilzomib non-refractory multiple myeloma patients

BACKGROUND

Proteasome inhibitors (PIs), including carfilzomib, potentiate the activity of selinexor, a novel, first-in-class, oral selective inhibitor of nuclear export (SINE) compound, in preclinical models of multiple myeloma (MM).

METHODS

The safety, efficacy, maximum-tolerated dose (MTD) and recommended phase 2 dose (RP2D) of selinexor (80 or 100 mg) + carfilzomib (56 or 70 mg/m2) + dexamethasone (40 mg) (XKd) once weekly (QW) was evaluated in patients with relapsed refractory MM (RRMM) not refractory to carfilzomib.

RESULTS

Thirty-two patients, median prior therapies 4 (range, 1-8), were enrolled. MM was triple-class refractory in 38% of patients and 53% of patients had high-risk cytogenetics del(17p), t(4;14), t(14;16) and/or gain 1q. Common treatment-related adverse events (all/Grade 3) were thrombocytopenia 72%/47% (G3 and G4), nausea 72%/6%, anaemia 53%/19% and fatigue 53%/9%, all expected and manageable with supportive care and dose modifications. MTD and RP2D were identified as selinexor 80 mg, carfilzomib 56 mg/m2, and dexamethasone 40 mg, all QW. The overall response rate was 78% including 14 (44%) ≥ very good partial responses. Median progression-free survival was 15 months.

CONCLUSIONS

Weekly XKd is highly effective and well-tolerated. These data support further investigation of XKd in patients with MM.

Targeting Nuclear Export Proteins in Multiple Myeloma Therapy

Nuclear export proteins such as exportin-1 (XPO1) transport tumor-suppressor proteins and other growth-regulatory proteins from the nucleus to the cytoplasm. Overexpression of XPO1 has been observed in several cancers and correlates with shorter event-free and overall survival in multiple myeloma. Selinexor was developed as an oral first-in-class selective inhibitor of nuclear export (SINE) that inhibits XPO1. Preclinical studies in tumor cell lines and mouse models have demonstrated the efficacy of selinexor both as a single agent and in various combinations with known active antimyeloma agents. Results from the pivotal phase II STORM trial led to the US FDA approval of selinexor with dexamethasone in penta-refractory myeloma. Because of the feasibility of combining selinexor with other active antimyeloma agents, the multiarm STOMP trial was initiated and is ongoing, with impressive response rates reported in some of the combination arms thus far. The registrational phase III BOSTON trial demonstrated the superiority of selinexor in combination with bortezomib and dexamethasone as compared with bortezomib and dexamethasone in patients with relapsed refractory multiple myeloma (RRMM) who have received one to three prior anti-MM regimens. The toxicity profile of selinexor is well established and predictable and may be significant unless managed aggressively and preemptively. The most common side effects are thrombocytopenia, anemia, neutropenia, fatigue, nausea, anorexia, and weight loss. Hyponatremia and cataracts seem to be class effects. Other SINE compounds are now being studied in efforts to discover agents that will potentially be better tolerated. Eltanexor is an investigational SINE compound that has shown a more positive toxicity profile in preclinical studies, with reduced central nervous system penetration and gastrointestinal side effects, and is now undergoing clinical investigation. These and other trials will further clarify the role of these innovative agents in the therapeutic advancement of RRMM.