Daratumumab resistance is frequent in advanced-stage multiple myeloma patients irrespective of CD38 expression and is related to dismal prognosis

From Triple- to Penta-Exposed Multiple Myeloma: A Real-World Study in a Medicare Population

INTRODUCTION

Treatment of multiple myeloma (MM) has been transformed by novel therapies, including CD38 monoclonal antibodies (mAbs), immunomodulatory drugs (IMiDs), and proteasome inhibitors (PIs), resulting in increasing numbers of patients who are triple-class exposed (TCE; exposed to ≥ 1 drug in each class). Many patients are penta-exposed (PE; ≥ 2 IMiDs, ≥ 2 PIs, and a CD38 mAb), some are triple-class refractory (TCR), and some are PE and TCR (PE-TCR). Data on real-world outcomes in elderly patients with MM across this spectrum of exposure are limited.

METHODS

Data from the Medicare Chronic Conditions Warehouse Database from November 2006-December 2020 were used to examine cohorts of TCE, TCR, PE, and PE-TCR patients. Outcomes were assessed from the start of the index line of therapy (LOT), defined as the first LOT after becoming TCE or PE.

RESULTS

A total of 2830 TCE, 1371 TCR, 1121 PE, and 774 PE-TCR patients were identified. Pomalidomide was the most frequently used medication for the index LOT in all cohorts (32.6% [PE-TCR] to 43.3% [TCR]). The most frequently used regimens for the index LOT were pomalidomide plus daratumumab for TCE (17.2%) and PE (7.0%), pomalidomide plus carfilzomib for TCR (10.3%), and pomalidomide plus elotuzumab for PE-TCR (7.4%). Median time to discontinuation (TTD) ranged from 4.2 (PE-TCR) to 6.9 (TCE) months, and overall survival (OS) ranged from 13.0 (TCR) to 15.9 (PE) months. Healthcare resource utilization (HRU) was lowest for TCE and highest for PE-TCR patients. Mean monthly healthcare costs (HCC) ranged from $23,091 (TCE) to $24,412 (PE-TCR). MM medications represented 66.2% (PE-TCR) to 72.8% (TCE) of costs.

CONCLUSIONS

In this study across a spectrum of Medicare TCE patients, there was heterogeneity in treatment regimens, suggesting no standard of care. TTD and OS were short, and HRU and HCC were high. These results underscore the potential for new therapies in this population.

Research strategies of small molecules as chemotherapeutics to overcome multiple myeloma resistance

Multiple myeloma (MM), a cancer of plasma cells, is the second most common hematological malignancy which is characterized by aberrant plasma cells infiltration in the bone marrow and complex heterogeneous cytogenetic abnormalities. Over the past two decades, novel treatment strategies such as proteasome inhibitors, immunomodulators, and monoclonal antibodies have significantly improved the relative survival rate of MM patients. However, the development of drug resistance results in the majority of MM patients suffering from relapse, limited treatment options and uncontrolled disease progression after relapse. There are urgent needs to develop and explore novel MM treatment strategies to overcome drug resistance and improve efficacy. Here, we review the recent small molecule therapeutic strategies for MM, and introduce potential new targets and corresponding modulators in detail. In addition, this paper also summarizes the progress of multi-target inhibitor therapy and protein degradation technology in the treatment of MM.

Efficacy of elotuzumab for multiple myeloma deteriorates after daratumumab: a multicenter retrospective study

Elotuzumab-based regimens are sometimes selected for multiple myeloma treatment after daratumumab-based regimens. However, there has been insufficient discussion on the efficacy of elotuzumab after daratumumab. We used Kansai Myeloma Forum registration data in a multicenter retrospective evaluation of the efficacy of elotuzumab after daratumumab. Overall survival (OS) rate and time to next treatment (TTNT) were significantly worse in the cohort given elotuzumab after daratumumab (Dara cohort, n = 47) than in the cohort with no history of daratumumab administration before elotuzumab (No-Dara cohort, n = 80, OS: P = 0.03; TTNT: P = 0.02; best response: P < 0.01). In the Dara cohort, OS and TTNT rates were worse with sequential elotuzumab use after daratumumab than with non-sequential (OS: P = 0.02; TTNT: P = 0.03). In patients given elotuzumab < 180 days after daratumumab, OS (P = 0.08) and best response (P = 0.21) tended to be worse, and TTNT was significantly worse (P = 0.01), than in those given elotuzumab after ≥ 180 days. These findings were confirmed by subgroup analyses and multivariate analyses. Monoclonal-antibody-free treatment might be preferable after daratumumab-based regimens. If possible, elotuzumab-based regimens should be considered only ≥ 180 days after daratumumab use.

Multiparametric Flow Cytometry in the Evaluation of Plasma Cell Proliferative Disorders: Current Paradigms for Clinical Practice

Diagnosis of plasma cell proliferative disorders (PCPDs) is primarily based on the demonstration of monoclonal protein (M-Protein) in blood and/ or urine which often precedes clinical manifestations of the disease. The basic pathophysiology behind the M-protein presence is the proliferation of clonal plasma cells (PCs) in bone marrow or extramedullary sites and is assessed using cytomorphology and immunophenotyping. The role of multiparametric flow cytometry (MFC) for PC identification is technically the most valuable tool in this context as it characterizes as well as quantifies the clonal PCs based on differential expression of various immunophenotypic (IPT) markers. From a diagnostic perspective, MFC is critical in the definite identification of the clonal PCs and delineates benign and borderline entities at one end of the spectrum (MGUS, SMM) with lower clonal PC% and, malignant diseases at the other end (MM and PCL) with higher clonal PC fraction. The role of MFC in assessment of measurable residual disease (MRD) and monitoring of progression in MM and various PCPDs has been validated in multiple clinical studies and is probably one of the most promising tools for predicting treatment outcomes. Furthermore, MFC also plays a crucial role in disease prognostication based on specific IPT profiles. An additional role of MFC in the current clinical scenario is the evaluation of tumor microenvironment based on immune cell repertoire, which is reflecting encouraging results across. Thus, in the current review we concisely describe the role of MFC as a reliable and essential modality in PCPDs, from diagnosis to prediction of treatment outcome and disease monitoring.

Mezigdomide plus Dexamethasone in Relapsed and Refractory Multiple Myeloma

BACKGROUND

Despite recent progress, multiple myeloma remains incurable. Mezigdomide is a novel cereblon E3 ubiquitin ligase modulator with potent antiproliferative and tumoricidal activity in preclinical models of multiple myeloma, including those resistant to lenalidomide and pomalidomide.

METHODS

In this phase 1-2 study, we administered oral mezigdomide in combination with dexamethasone to patients with relapsed and refractory myeloma. The primary objectives of phase 1 (dose-escalation cohort) were to assess safety and pharmacokinetics and to identify the dose and schedule for phase 2. In phase 2 (dose-expansion cohort), objectives included the assessment of the overall response (partial response or better), safety, and efficacy of mezigdomide plus dexamethasone at the dose and schedule determined in phase 1.

RESULTS

In phase 1, a total of 77 patients were enrolled in the study. The most common dose-limiting toxic effects were neutropenia and febrile neutropenia. On the basis of the phase 1 findings, investigators determined the recommended phase 2 dose of mezigdomide to be 1.0 mg, given once daily in combination with dexamethasone for 21 days, followed by 7 days off, in each 28-day cycle. In phase 2, a total of 101 patients received the dose identified in phase 1 in the same schedule. All patients in the dose-expansion cohort had triple-class-refractory multiple myeloma, 30 patients (30%) had received previous anti-B-cell maturation antigen (anti-BCMA) therapy, and 40 (40%) had plasmacytomas. The most common adverse events, almost all of which proved to be reversible, included neutropenia (in 77% of the patients) and infection (in 65%; grade 3, 29%; grade 4, 6%). No unexpected toxic effects were encountered. An overall response occurred in 41% of the patients (95% confidence interval [CI], 31 to 51), the median duration of response was 7.6 months (95% CI, 5.4 to 9.5; data not mature), and the median progression-free survival was 4.4 months (95% CI, 3.0 to 5.5), with a median follow-up of 7.5 months (range, 0.5 to 21.9).

CONCLUSIONS

The all-oral combination of mezigdomide plus dexamethasone showed promising efficacy in patients with heavily pretreated multiple myeloma, with treatment-related adverse events consisting mainly of myelotoxic effects. (Funded by Celgene, a Bristol-Myers Squibb Company; CC-92480-MM-001 ClinicalTrials.gov number, NCT03374085; EudraCT number, 2017-001236-19.).

Clinical Outcomes of Patients with Multiple Myeloma after Daratumumab Failure

Anti-CD38 monoclonal antibody (MoAB) therapy has significantly improved the prognosis of patients with multiple myeloma. However, not all patients sustain durable responses. We aimed to describe the natural history of patients relapsed or refractory (R/R) to CD38 MoAB therapy. We performed a single-center, retrospective analysis of the clinical characteristics and outcomes of 81 patients with multiple myeloma who progressed after treatment with daratumumab. Our cohort was heavily pretreated, with a median of two lines prior to daratumumab and only 17 patients received daratumumab as a first line. A total of 38.2% had received a previous autologous stem cell transplantation (ASCT), and 61.7% had received both an immunomodulatory drug (IMID) and a proteasome inhibitor (PI). The median overall survival (OS) was 21 months for the global cohort but it decreased to 14 months for triple-class refractory patients and 5 months for penta-refractory patients. Most of the patients (83.9%) received treatment after daratumumab progression, in many cases with second generation IMID or PI, but seven patients were treated with anti-BCMA therapy and three patients received CART therapy within a clinical trial. In conclusion, patients R/R to daratumumab represent an unmet clinical need with poor prognosis and in need of incorporation of new treatments.

Sequential CAR T cell and targeted alpha immunotherapy in disseminated multiple myeloma

Multiple myeloma (MM) is still an incurable disorder despite improved antibody and cellular therapies against different MM antigens. Single targeted antigens have so far been ineffective against MM with most patients relapsing after initial response. Hence, sequential immunotherapies directed at different targets are expected to perform better than monotherapy alone. Here, we optimized and established in preclinical studies the therapeutic rationale of using targeted alpha therapy (TAT) directed against CD38 antigen (²²⁵Ac-DOTA-daratumumab) with CAR T cell therapy directed at CS1 antigen in a systemic MM model. The sequential therapies compared CAR T therapy followed by TAT to TAT followed by CAR T therapy. CAR T cell monotherapy increased median survival from 49 days (d) in untreated controls to 71d with a modest improvement to 89d for 3.7 kBq of TAT given 14d later. When CAR T was followed by 7.4 kBq of TAT 29d later, sequential therapy increased median survival from 47d in untreated controls to 106d, compared to 68d for CAR T monotherapy. When CAR T therapy was followed by untargeted alpha immunotherapy using 7.4 kBq of ²²⁵Ac-DOTA-trastuzumab (anti-HER2) antibody 29d later, there was only a slight improvement in response over CAR T monotherapy demonstrating the role of tumor targeting. TAT (7.4 kBq) followed by CAR T therapy was also effective when CAR T therapy was delayed for 21d vs 14d or 28d post TAT, highlighting the importance of timing sequential therapies. Sequential targeted therapies using CS1 CAR T or ²²⁵Ac-DOTA-CD38 TAT in either order shows promise over monotherapies alone.

Real-world treatment patterns and outcomes of triple-class treated patients with multiple myeloma in the United States

OBJECTIVES

Although multiple myeloma (MM) survival has improved following the introduction of proteosome inhibitors, immunomodulatory drugs, and anti-CD38 therapies, patients become refractory to these agents. Real-world outcomes of triple-class exposed patients are limited and were investigated in this study.

METHODS

The Integra Connect Database was used to assess the treatment patterns of triple-class exposed patients with relapsed/refractory MM (RRMM) (January 2016-December 2019).

RESULTS

During this period, patients (N = 501) reached triple exposure in a median of three lines of therapy (LOTs) over 995 days. A new LOT was started in a median of 18 (1-691) days after triple exposure; 71% of the patients started a new LOT within 30 days. Throughout the follow-up period, 8% of the patients had a therapy gap greater than 90 days. Following triple exposure, 103/501 patients (21%) received only triple-class agents in subsequent LOTs, while 24 (4.8%) patients received only non-triple-class agents. The median apparent survival from initiation of first therapy after triple exposure was 308 days.

CONCLUSION

These results indicate that recycling of triple-class agents after previous exposure is widespread and prognosis in the RRMM population remains poor, highlighting the continuing unmet need for new agents with novel mechanisms to improve patient outcomes.

Bridging advanced myeloma patients to subsequent treatments and clinical trials with classical chemotherapy and stem cell support

Rapidly progressing relapsed/refractory multiple myeloma (RRMM) patients with compromised marrow have limited treatment options. Thus, non-myeloablative chemotherapy with a stem cell boost (SCB) may provide disease control and hematopoietic improvement as bridge to subsequent therapies. We identified 96 patients who received a SCB between January 2011 and December 2019 at the Mount Sinai Hospital. Patients had a median age of 64 years, received a median of 7 prior lines of therapy and 68 and 42% were triple-class and penta-drug refractory, respectively. Chemotherapy included melphalan (MEL) (n = 16), melphalan + carmustine (BCNU/MEL) (n = 52) or a variant of DCEP (dexamethasone, cyclophosphamide, etoposide, cisplatin) (n = 28). Median time to neutrophil recovery was 10 days and was significantly lower with DCEP (8 days) compared to MEL and BCNU/MEL (10-11 days) (p = 0.0047). Time to progression, progression-free survival and overall survival were 3.19, 2.7 and 8.38 months, respectively. The BCNU/MEL group had the highest response rate of 85% (p = 0.05), clinical benefit rate of 94% (p = 0.0014), progression-free survival of 3.3 months (p = 0.4) and overall survival of 8.7 months (p = 0.5). Sixty-six patients (69%) were bridged to new lines of therapy, including clinical trials. Non-myeloablative chemotherapy with SCB provides rapid disease control and marrow recovery with potential to receive further therapy.

Extracellular Vesicles in Multiple Myeloma-Cracking the Code to a Better Understanding of the Disease

Multiple myeloma (MM) is a plasma cell-derived malignancy that stands for around 1.5% of newly discovered cancer cases. Despite constantly improving treatment methods, the disease is incurable with over 13,000 deaths in the US and over 30,000 in Europe. Recent studies suggest that extracellular vesicles (EVs) might play a significant role in the pathogenesis and evolution of MM. Further investigation of their role could prove to be beneficial in establishing new therapies and hence, improve the prognosis of MM patients. What is more, EVs might serve as novel markers in diagnosing and monitoring the disease. Great advancements concerning the position of EVs in the pathophysiology of MM have recently been shown in research and in this review, we would like to delve into the still expanding state of knowledge.

Advances in the treatment of extramedullary disease in multiple myeloma

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Extramedullary multiple myeloma results in an adverse prognosis.

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Novel agents such as bortezomib, lenalidomide, pomalidomide, isatuximab and selinexor showed efficacy and were recommended to treat EMD.

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For EMD at special sites, marizomib has advantages in the treatment of CNS-MM; Daratumumab combining with intrapleural bortezomib administration is active in treating myelomatous pleural effusion.

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Based on treatment experience of EMD in our department, we summarized treatment approach for EMD.

Extramedullary disease (EMD) is characterized by plasma cells outside of bone marrow in multiple myeloma (MM) patients, which results in an adverse prognosis. The cornerstone of treatment consists of combination therapy including proteasome inhibitors, immunomodulatory agents, steroids, followed by consolidative autologous hematopoietic stem cell transplantation in eligible patients. This review summarized the recent advances in the treatment of EMD. Bortezomib based therapy showed efficacy and was recommended to treat EMD. Marizomib had advantages in the treatment of central nervous system-multiple myeloma (CNS-MM) because of its good central nervous system penetrability. Immunomodulatory drugs such as lenalidomide and pomalidomide have been reported to be effective. Isatuximab and selinexor were also active. Based on the treatment experience of EMD in our department, we summarized treatment approach for EMD. However, the benefits of patients with EMD from the new era of novel drugs were limited. Novel drugs combination, monoclonal antibody, molecular targeted therapy, cellular immunotherapy and autologous stem cell transplantation (ASCT) are under investigation. Therapeutic studies and clinical trials specifically target EMD should be conducted. Hopefully, these treatment options for EMD will be demonstrated efficacy in the future.

Efficacy and safety of intravenous daratumumab-based treatments for AL amyloidosis: a systematic review and meta-analysis

BACKGROUND

Intravenous daratumumab (DARA IV) has been increasingly used in the treatment of amyloid light-chain (AL) amyloidosis. However, the outcomes for patients administered with DARA IV have not been aggregated. The objective of this systematic review and meta-analysis was to investigate the efficacy and safety of DARA IV for AL amyloidosis.

METHODS

We searched Medline, EMBASE, Cochrane Library and Web of Science up to 17 June 2021. Response rates and survival rates, and the corresponding 95% confidence intervals (CIs) were pooled and calculated using a fixed-effects model.

RESULTS

Thirty studies (5 cohort studies and 25 single-arm studies) with 997 patients were included. In patients receiving DARA IV-based treatments, very good partial response or better response rate, complete response rate, very good partial response rate, partial response rate and overall response rate were 66% (95% CI, 62-69%), 30% (95% CI, 23-36%), 40% (95% CI, 33-46%), 17% (95% CI, 14-21%), and 77% (95% CI, 73-80%), respectively. Cardiac and renal responses were 41% (95% CI, 34-49%) and 43% (95% CI, 32-54%), respectively. 58% (95% CI, 49-66%) of patients achieved PFS one year or longer. 2.5% (range, 1-10.0%) of patients experienced grade 3 or 4 adverse events, of which the most common adverse event was lymphocytopenia (range, 13.6-25.0%).

CONCLUSION

This study supports the efficacy and safety of DARA IV for the treatment of patients with AL amyloidosis.

Bilateral Orbital Plasmacytomas With Orbital Compartment Syndrome

Orbital plasmacytomas are uncommon soft-tissue plasma cell neoplasms that are associated with a monoclonal or myeloma protein. There are four types of plasma cell neoplasms: multiple myeloma (MM), monoclonal gammopathy of undetermined significance (MGUS), amyloidosis, and plasmacytoma. Plasmacytomas may be classified as medullary, occurring only within the bone, or extramedullary, occurring in soft tissues. Orbital plasmacytomas are extramedullary manifestations associated with MM and they may present with signs and symptoms such as unilateral proptosis, conjunctival injection, ocular pain, diplopia, and vision changes. The diagnosis of orbital plasmacytomas is based on tissue biopsy and histologic and immunohistochemical confirmation of a homogenous infiltrate of monoclonal plasma cells.

In this report, we present a case of a 60-year-old female patient with a prior diagnosis of MM and new-onset bilateral orbital plasmacytomas following an autologous peripheral blood stem cell transplant; her condition improved significantly following treatment with dexamethasone, cisplatin, doxorubicin, cyclophosphamide, and etoposide along with palliative radiation therapy (RT) of 2000 cGy in 10 fractions to the orbits. Unfortunately, three months later, she had progression of extramedullary disease with parotid gland involvement. She had multiple complicated hospitalizations and eventually expired. As patients with orbital plasmacytomas classically have lower remission and survival rates compared to those with extramedullary plasmacytomas involving other locations, they must be considered high-risk patients who require a multidisciplinary approach for early diagnosis and timely treatment in order to prevent disease progression and to alleviate symptoms related to the disease.

The role of E3 ubiquitin ligase in multiple myeloma: potential for cereblon E3 ligase modulators in the treatment of relapsed/refractory disease

INTRODUCTION

Insights into the mechanisms of protein homeostasis and proteasomal degradation have led to new strategies of redirecting the ubiquitin-proteasome system (UPS) to reduce or eliminate proteins or survival factors key to malignant pathobiology, multiple myeloma (MM) in particular. These strategies have enabled researchers to target proteins that were previously considered difficult to modulate by pharmacological means.

AREAS COVERED

This review provides a brief overview of UPS biology, particularly the role of the CRL4^CRBN E3 ubiquitin ligase complex, and summarizes current strategies for co-opting the UPS, including CELMoD compounds, SNIPERs, PROTACs, and degronimids. A detailed discussion is provided on lead CELMoD compounds iberdomide and mezigdomide, which are currently being evaluated in clinical trials in patients with MM.

EXPERT OPINION

Since a high proportion of patients develop drug resistance, it is vital to have novel therapeutic agents for treating relapsed patients with MM more effectively. It is encouraging that the expanding pathophysiological insight into cellular signaling pathways in MM increasingly translates into the development of novel therapeutic agents such as targeted protein degraders. This holds promise for improving outcomes in MM and beyond.

BCMA-Targeted Biologic Therapies: The Next Standard of Care in Multiple Myeloma Therapy

With recent advances in myeloma therapy, patients can achieve long-term remissions, but eventually relapses will occur. Triple-class refractory myeloma (disease that is refractory to an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody) and penta-refractory myeloma (disease that is refractory to two proteasome inhibitors, two immunomodulatory agents, and an anti-CD38 antibody) are associated with a particularly poor prognosis, and novel treatments are desperately needed for these patients. Targeting B cell maturation antigen (BCMA), which is ubiquitously expressed on plasma cells, has emerged as a well-tolerated and highly efficacious strategy in patients with relapsed and refractory myeloma. Several mechanisms of targeting BCMA are currently under investigation, including antibody-drug conjugates, bispecific antibodies, and chimeric antigen receptor T cells and natural killer (NK) cells, all with unique side effect profiles. Early phase clinical trials showed unprecedented response rates in highly refractory myeloma patients, leading to the recent approvals of some of these agents. Still, many questions remain with regard to this target, including how best to target it, how to treat patients who have progressed on a BCMA-targeting therapy, and whether response rates will deepen if these agents are used in earlier lines of therapy. In this review, we examine the rationale for targeting BCMA and summarize the data for several agents across multiple classes of BCMA-targeting therapeutics, paying special attention to the diverse mechanisms and unique challenges of each therapeutic class.

Understanding the Bioactivity and Prognostic Implication of Commonly Used Surface Antigens in Multiple Myeloma

Multiple myeloma (MM) progression is dependent on its interaction with the bone marrow microenvironment and the immune system and is mediated by key surface antigens. Some antigens promote adhesion to the bone marrow matrix and stromal cells, while others are involved in intercellular interactions that result in differentiation of B-cells to plasma cells (PC). These interactions are also involved in malignant transformation of the normal PC to MM PC as well as disease progression. Here, we review selected surface antigens that are commonly used in the flow cytometry analysis of MM for identification of plasma cells (PC) and the discrimination between normal and malignant PC as well as prognostication. These include the markers: CD38, CD138, CD45, CD19, CD117, CD56, CD81, CD27, and CD28. Furthermore, we will discuss the novel marker CD24 and its involvement in MM. The bioactivity of each antigen is reviewed, as well as its expression on normal vs. malignant PC, prognostic implications, and therapeutic utility. Understanding the role of these specific surface antigens, as well as complex co-expressions of combinations of antigens, may allow for a more personalized prognostic monitoring and treatment of MM patients.

SAR442085, a novel anti-CD38 antibody with enhanced antitumor activity against multiple myeloma

Anti-CD38 monoclonal antibodies (mAbs) represent a breakthrough in the treatment of multiple myeloma (MM), yet some patients fail to respond or progress quickly with this therapy, highlighting the need for novel approaches. In this study we compared the preclinical efficacy of SAR442085, a next-generation anti-CD38 mAb with enhanced affinity for activating Fcγ receptors (FcγR), with first-generation anti-CD38 mAb daratumumab and isatuximab. In surface plasmon resonance and cellular binding assays, we found that SAR442085 had higher binding affinity than daratumumab and isatuximab for FcγRIIa (CD32a) and FcγRIIIa (CD16a). SAR442085 also exhibited better in vitro antibody-dependent cellular cytotoxicity (ADCC) against a panel of MM cells expressing variable CD38 receptor densities including MM patients' primary plasma cells. The enhanced ADCC of SAR442085 was confirmed using NK-92 cells bearing low and high affinity FcγRIIIa (CD16a)-158F/V variants. Using MM patients' primary bone marrow cells, we confirmed that SAR442085 had an increased ability to engage FcγRIIIa, resulting in higher natural killer (NK) cell activation and degranulation against primary plasma cells than preexisting Fc wild-type anti-CD38 mAbs. Finally, using huFcgR transgenic mice that express human Fcγ receptors under the control of their human regulatory elements, we demonstrated that SAR442085 had higher NK cell-dependent in vivo antitumor efficacy and better survival than daratumumab and isatuximab against EL4 thymoma or VK*MYC myeloma cells overexpressing human CD38. These results highlight the preclinical efficacy of SAR442085 and support the current evaluation of this next-generation anti-CD38 antibody in phase I clinical development in patients with relapsed/refractory MM.

Research progress on treatment of extramedullary multiple myeloma

ABSTRACTObjectives: Extramedullary multiple myeloma (EMM) is a relatively less frequent subentity of multiple myeloma (MM) and is generally considered to be a poor prognostic factor. Novel agents and hematopoietic stem cell transplantation (HSCT) have led to a significant improvement in the progression-free survival and overall survival of patients with MM, but outcomes of EMM remain dismal. Little is known regarding the role of novel therapies in this setting. This review summarizes the current available data regarding the roles of proteasome inhibitors, immunomodulators, monoclonal antibodies, chimeric antigen receptor (CAR)-T cell therapy and HSCT in EMM.Methods: A systematic literature review through PubMed was conducted to summarize the published evidence on the therapeutic developments of novel agents and HSCT in EMM. Literature sources published in English were searched, using the terms multiple myeloma, extramedullary and treatment.Results: Long-term outcomes of EMM patients remain dismal despite the utilization of novel agents and HSCT. The standard therapy of EMM has not been established. EMM should be managed as high-risk disease and treated accordingly.Discussion and conclusion: This review will provide an insight on the current and emerging treatment strategies as well as their efficacy in EMM. Further subgroup analyses in large prospective trials focusing on EMM is needed to help optimize the therapy.

Anti-BCMA CAR-T Cell Therapy in Relapsed/Refractory Multiple Myeloma Patients With Extramedullary Disease: A Single Center Analysis of Two Clinical Trials

Background

The prognosis of relapsed/refractory multiple myeloma (RRMM) patients with the extramedullary disease was significantly poor. Extramedullary multiple myeloma (EMM) patients gained limited benefits from traditional drugs. Anti-B cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy seems to be a promising approach to treat RRMM patients. However, very few clinical studies are designed for EMM. Our study aimed to compare and assess the safety, efficacy, and pharmacokinetics of anti-BCMA CAR-T cell therapy in EMM and non-EMM.

Methods

The results from published anti-BCMA CAR-T clinical trials, in which raw data of EMM patients were available, were reviewed and summarized. Two trials conducted in our clinical centers were analyzed and presented with detailed data.

Results

According to published anti-BCMA CAR-T clinical trials, the ORR of EMM ranged from 57% to 100%, with the complete remission (CR) rate of 29% to 60%. Between February 22, 2017, and September 26, 2019, a total of 61 subjects (EMM 25; non-EMM 36) received anti-BCMA CAR-T cell infusion. The data-cutoff date was April 1, 2021. There were no statistical differences between EMM and non-EMM groups in adverse events (AEs), including cytokine release syndrome (CRS). The most common AEs of grade ≥ 3 in both groups were hematologic toxicities. There was no significant difference in the objective response rate (ORR) and ≥ complete remission (CR) rate between both groups. However, the ≥ CR rate of the EMM group was lower than the non-EMM group receiving the fully human anti-BCMA CAR-T cell therapy (p = 0.026). The median progression-free survival (PFS) for EMM and the non-EMM group was 121 days and 361 days, respectively (p = 0.001). The median overall survival (OS) for EMM and the non-EMM group was 248 days and 1024 days, respectively (p = 0.005). The C_max and AUC_0-28d for EMM group were lower than non-EMM group (C_max, p = 0.016; AUC_0-28d, p = 0.016). Extramedullary disease was an independent prognostic risk factor for PFS (hazard ratio, 2.576; 95% CI, 1.343 to 4.941; p = 0.004) and OS (hazard ratio, 2.312; 95% CI, 1.165 to 4.592; p = 0.017) in RRMM patients receiving anti-BCMA CAR-T cell therapy.

Conclusions

Based on our results, EMM patients could benefit from the two anti-BCMA CAR products, although they had a shorter PFS and OS compared with non-EMM patients.

Clinical Trial Registration

http://www.chictr.org.cn, identifier ChiCTR-OPC-16009113 and ChiCTR1800018137.

The Role of Monoclonal Antibodies in the Era of Bi-Specifics Antibodies and CAR T Cell Therapy in Multiple Myeloma

Multiple myeloma (MM) remains largely incurable despite enormous improvement in the outcome of patients. Over the past decade, we have witnessed the "era of monoclonal antibody (moAb)", setting new benchmarks in clinical outcomes for relapsed and newly diagnosed MM. Due to their excellent efficacy and relative safe toxicity profile, moAbs in combination with immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs) have become the new backbone of upfront anti-MM therapy. Yet, most patients will eventually relapse and patients who become refractory to IMiDs, PIs and moAbs have a dismal outcome. Emerging T-cell directing therapies, such as bispecific antibody (bsAb) and chimeric antigen receptor T cells (CAR T) have shown unprecedented responses and outcomes in these heavily pretreated and treatment-refractory patients. Their clinical efficacy combined with high tolerability will likely lead to the use of these agents earlier in the treatment course and there is great enthusiasm that a combination of T cell directed therapy with moAbs can lead to long duration remission in the near future, possibly even without the need of high dose chemotherapy and stem cell transplantation. Herein, we summarize the role of naked moAbs in MM in the context of newer immunotherapeutic agents like bsAb and CAR T therapy.

Tissue biodistribution and tumor targeting of near-infrared labelled anti-CD38 antibody-drug conjugate in preclinical multiple myeloma

Daratumumab (DARA) is an FDA-approved high-affinity monoclonal antibody targeting CD38 that has shown promising therapeutic efficacy in double refractory multiple myeloma (MM) patients. Despite the well-established clinical efficacy of DARA, not all heavily pretreated patients respond to single-agent DARA, and the majority of patients who initially respond eventually progress. Antibody-drug conjugates (ADCs) combine the highly targeted tumor antigen recognition of antibodies with the cell killing properties of chemotherapy for effective internalization and processing of the drug. In this study, we evaluated the anti-tumor efficacy of DARA conjugated to the maytansine derivative, mertansine (DM1), linked via a non-cleavable bifunctional linker. The ADC was labelled with the near-infrared (NIR) fluorophore IRDye800 (DARA-DM1-IR) to evaluate its stability, biodistribution and pharmacokinetics in vitro and in vivo. We demonstrated the conjugation of: 1) DM1 enhanced tumor-killing efficacy of the native DARA and 2) IRDye800 allowed for visualization of uptake and tumor targeting ability of the ADC. With the advent of other classes of immunoconjugates for use in MM, we reasoned that such imaging techniques can be utilized to evaluate other promising conjugates in preclinical MM models on a whole-body and cellular level.

Quality of life analyses in patients with multiple myeloma: results from the Selinexor (KPT-330) Treatment of Refractory Myeloma (STORM) phase 2b study

BACKGROUND

Selinexor is an oral, selective nuclear export inhibitor. STORM was a phase 2b, single-arm, open-label, multicenter trial of selinexor with low dose dexamethasone in patients with penta-exposed relapsed/refractory multiple myeloma (RRMM) that met its primary endpoint, with overall response of 26% (95% confidence interval [CI], 19 to 35%). Health-related quality of life (HRQoL) was a secondary endpoint measured using the Functional Assessment of Cancer Therapy - Multiple Myeloma (FACT-MM). This study examines impact of selinexor treatment on HRQoL of patients treated in STORM and reports two approaches to calculate minimal clinically important differences for the FACT-MM.

METHODS

FACT-MM data were collected at baseline, on day 1 of each 4-week treatment cycle, and at end of treatment (EOT). Changes from baseline were analyzed for the FACT-MM total score, FACT-trial outcome index (TOI), FACT-General (FACT-G), and the MM-specific domain using mixed-effects regression models. Two approaches for evaluating minimal clinically important differences were explored: the first defined as 10% of the instrument range, and the second based on estimated mean baseline differences between Eastern Cooperative Oncology Group performance status (ECOG PS) scores. Post-hoc difference analysis compared change in scores from baseline to EOT for treatment responders and non-responders.

RESULTS

Eighty patients were included in the analysis; the mean number of prior therapies was 7.9 (standard deviation [SD] 3.1), and mean duration of myeloma was 7.6 years (SD 3.4). Each exploratory minimal clinically important difference threshold yielded consistent results whereby most patients did not experience HRQoL decline during the first six cycles of treatment (range: 53.9 to 75.7% for the first approach; range: 52.6 to 72.9% for the second). Treatment responders experienced less decline in HRQoL from baseline to EOT than non-responders, which was significant for the FACT-G, but not for other scores.

CONCLUSION

The majority of patients did not experience decline in HRQoL based on minimal clinically important differences during early cycles of treatment with selinexor and dexamethasone in the STORM trial. An anchor-based approach utilizing patient-level data (ECOG PS score) to define minimal clinically important differences for the FACT-MM gave consistent results with a distribution-based approach.

TRIAL REGISTRATION

This trial was registered on ClinicalTrials.gov under the trial-ID NCT02336815 on January 8, 2015.

Extramedullary multiple myeloma patient-derived orthotopic xenograft with a highly altered genome: combined molecular and therapeutic studies

Extramedullary multiple myeloma (EMM) has an overall survival of 6 months and occurs in 20% of multiple myeloma (MM) patients. Genetic and epigenetic mechanisms involved in EMM and the therapeutic role of new agents for MM are not well established. Besides, well-characterized preclinical models for EMM are not available. Herein, a patient-derived orthotopic xenograft (PDOX) was generated from a patient with an aggressive EMM to study in-depth genetic and epigenetic events, and drug responses related to extramedullary disease. A fresh punch of an extramedullary cutaneous lesion was orthotopically implanted in NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ(NSG) mouse. The PDOX mimicked histologic and phenotypic features of the tumor of the patient. Cytogenetic studies revealed a hyperploid genome with multiple genetic poor-prognosis alterations. Copy number alterations (CNAs) were detected in all chromosomes. The IGH translocation t(14;16)(q32;q23)IGH/MAF was already observed at the medullary stage and a new one, t(10;14)(p?11-12;q32), was observed only with extramedullary disease and could be eventually related to EMM progression in this case. Exome sequencing showed 24 high impact single nucleotide variants and 180 indels. From the genes involved, only TP53 was previously described as a driver in MM. A rather balanced proportion of hyper/hypomethylated sites different to previously reported widespread hypomethylation in MM was also observed. Treatment with lenalidomide, dexamethasone and carfilzomib showed a tumor weight reduction of 90% versus non-treated tumors, whereas treatment with the anti-CD38 antibody daratumumab showed a reduction of 46%. The generation of PDOX from a small EMM biopsy allowed us to investigate in depth the molecular events associated with extramedullary disease in combination with drug testing.

Immunotherapy in Multiple Myeloma-Time for a Second Major Paradigm Shift

Multiple myeloma (MM) is a genetically heterogenous disease and remains mostly incurable with a small group of patients achieving long-term disease remission. The past decade witnessed enormous efforts to break the circulus vitiosus of tumor-induced immunosuppression and to re-engage the immune system to fight cancer. The first-in-class anti-CD38 monoclonal antibody, daratumumab, has shown unprecedented responses especially in combination with other novel agents in both newly diagnosed and relapsed MM. There has been great interest in harnessing the power of T cells with bispecific antibodies and chimeric antigen receptor T-cell therapies in hematologic malignancies including MM. These immune-based approaches have shown notable antimyeloma effects with deeper, durable responses in early clinical trials of heavily pretreated patients with MM with limited therapeutic options. Several trials are underway investigating both single and combinatorial immune therapies at different stages with a hope to bring major transformation in MM. In the current review, we summarize how an immunologic approach offers promise for the treatment of MM and is setting the stage for second major paradigm shift 2 decades after the emergence of thalidomide and novel therapeutics.

Successful Treatment of Relapsed/Refractory Extramedullary Multiple Myeloma With Anti-BCMA CAR-T Cell Therapy Followed by Haploidentical Hematopoietic Stem Cell Transplantation: A Case Report and a Review of the Contemporary Literature

Extramedullary multiple myeloma (EMM) is an aggressive sub-entity of multiple myeloma (MM). Despite an excellent improvement in survival for most patients with MM over recent decades, the overall survival (OS) of patients with EMM was usually not longer than 3 years. Standard treatment for patients with EMM has not been established, and their management is particularly challenging. We presented a heavily pretreated young patient with relapsed EMM and refractoriness to a proteasome inhibitor (PI; bortezomib), a next-generation PI (ixazomib), immunomodulatory drugs (IMiDs; lenalidomide), autologous hematopoietic stem cell transplantation (ASCT), and monoclonal antibody (directed against CD38: daratumumab) and indicated that myeloablative haploidentical hematopoietic stem cell transplantation (haploidentical-HSCT) as a salvage treatment of relapse after a chimeric antigen receptor (CAR)-T cell therapy that targeted B-cell maturation antigen (BCMA) (NCT04650724) is feasible. Taken together of the contemporary literature, the promising results on the effect of anti-BCMA CAR-T cell therapy and allogeneic HSCT might present a proof-of-principle for patients with EMM, and therefore, patients with the disease need to be included in future studies.

[The efficacy and safety of daratumumab in relapsed and refractory multiple myeloma]

目的

探讨达雷妥尤单抗治疗复发/难治多发性骨髓瘤（RRMM）的疗效与安全性。

方法

回顾性分析2017年9月至2020年3月上海长征医院接受达雷妥尤单抗治疗的46例RRMM患者的临床资料。

结果

所有RRMM患者均采用以达雷妥尤单抗为基础的方案进行治疗，其中Dd（达雷妥尤单抗+地塞米松）方案组8例，DRd（达雷妥尤单抗+来那度胺+地塞米松）方案组35例，DVd（达雷妥尤单抗+硼替佐米+地塞米松）方案组3例。中位随访9.6个月，可评估疗效患者44例，总缓解率（ORR）75%[完全缓解（CR）率18.2%]。对硼替佐米、来那度胺及两者均耐药患者的ORR分别为70.6%（CR率17.6%）、69.2%（CR率11.5%）和63.6%（CR率13.6%），三组间差异无统计学意义。DRd组、DVd组和Dd组的ORR分别为85.3%、66.7%和28.6%（P＝0.007）。46例患者的中位无进展生存（PFS）时间为8.9个月，中位总生存（OS）时间未达到，1年OS率74%。DRd组中位PFS时间及OS时间较Dd组长（PFS时间：14.4个月对2.0个月；OS时间：未达到对5.2个月）。应用达雷妥尤单抗后，3级以上血液学不良反应以中性粒细胞减少最为常见，非血液学不良反应主要为输液相关不良反应和感染。预后分析显示伴髓外病灶患者的PFS时间和OS时间较不伴髓外病灶患者缩短（PFS时间：5.7个月对14.4个月，P＝0.033；OS时间：6.3个月对未达到，P＝0.029）；ECOG评分3～4分患者的OS时间较ECOG评分1～2分患者缩短（5.9个月对未达到，P＝0.004）。

结论

以达雷妥尤单抗为基础的方案治疗RRMM具有较好的疗效及安全性。

Belantamab mafodotin in combination with novel agents in relapsed/refractory multiple myeloma: DREAMM-5 study design

Belantamab mafodotin (belamaf) is a BCMA-targeted antibody-drug conjugate recently approved as monotherapy for adults with relapsed/refractory multiple myeloma who have received ≥4 prior therapies. Belamaf binds to BCMA and eliminates myeloma cells by multimodal mechanisms of action. The cytotoxic and potential immunomodulatory properties of belamaf have led to novel combination studies with other anticancer therapies. Here, we describe the rationale and design of DREAMM-5, an ongoing Phase I/II platform study evaluating the safety and efficacy of belamaf combined with novel agents, including GSK3174998 (OX40 agonist), feladilimab (an ICOS; GSK3359609), nirogacestat (a gamma-secretase inhibitor; PF-03084014) and dostarlimab (a PD-1 blocker) versus belamaf monotherapy for patients with relapsed/refractory multiple myeloma. Clinical trial registration: NCT04126200 (ClinicalTrials.gov).

Monoclonal antibodies in relapsed/refractory myeloma: updated evidence from clinical trials, real-life studies, and meta-analyses

Introduction: In the last few years, monoclonal antibodies have rapidly modified the therapeutic strategies for treating patients with multiple myeloma.Areas covered: In this review, the most recent literature data regarding indications for which monoclonal antibodies are currently or will be shortly approved as salvage therapies in relapsed/refractory myeloma are discussed. In particular, updated results until March 22, 2020 of antibodies directed against CD38 (daratumumab and isatuximab), SLAMF7 (elotuzumab), BCMA (GSK2857916/belantamab mafodotin), and PD-1/PD-1 L axis (nivolumab and pembrolizumab) will be analyzed in detail.Expert opinion: Monoclonal antibodies represent a new, very effective approach that will open novel and dynamic treatment scenarios for myeloma patients in the coming years. Optimal positioning and selection of different antibodies that are or will be soon available, appropriate combinations and careful evaluation of possible new toxicities should be considered in the future management of these patients.

Real-world treatment patterns, healthcare use and costs in triple-class exposed relapsed and refractory multiple myeloma patients in the USA

Aim: To estimate treatment patterns and healthcare costs among triple-class exposed relapsed and refractory multiple myeloma (RRMM) patients. Materials & methods: Eligible patients had ≥1 line of therapy (LOT) each of proteasome inhibitors, immunomodulatory drugs and daratumumab in December 2015-September 2018 and received a new LOT. Results: A total of 154 patients were included with a median follow-up of 6.2 months. Median time from diagnosis to new LOT was 41.0 months. Kaplan-Meier estimate of median time to therapy discontinuation was 4.2 months. Mean per-patient, per-month MM-related costs were USD 35,657. Most frequently observed regimens were lenalidomide or pomalidomide + daratumumab (18.2%), lenalidomide or pomalidomide + proteasome inhibitors (15.6%) and lenalidomide or pomalidomide monotherapy (11.0%). Conclusion: Triple-class exposed RRMM patients receive heterogeneous treatments for a short duration with high healthcare resource utilization and costs.

Real-World Outcome in the pre-CAR-T Era of Myeloma Patients Qualifying for CAR-T Cell Therapy

Background

CAR-T cell therapy is likely to be introduced starting from 2021 in patients with relapsed/refractory myeloma (r/r MM) in Europe. In order to qualify for commercial CAR-T treatment, it is assumed that r/r MM patients will have to be exposed to at least three lines of previous treatments including lenalidomide, bortezomib and anti-CD38 treatment. However, the outcome of this particular subgroup of r/r MM patients is largely unknown whereas this knowledge is crucial to estimate the possible benefit of eventual CAR-T treatment.

Methods

In this non-interventional, retrospective single-center study, we analyzed all subsequent r/r MM patients treated between 01/2016 (when anti-CD38 treatment was commercially introduced in Switzerland) and 04/2020 at the University Hospital of Bern. Patients were eligible for the study if they had received at least three lines of treatment including one proteasome inhibitor (PI), one immunomodulatory drug (IMID) and one anti-CD38 antibody, and if they were in need of subsequent treatment and effectively received further lines of treatment.

Results

Among 56 patients fulfilling the criteria of at least three lines of treatment including PI, IMID and anti-CD38 treatment, only 34 (60%) effectively received subsequent further therapy. This suggests that 40% of r/r MM patients never receive additional treatment after at least three lines of treatment including PI, IMID and anti-CD38 treatment. For patients receiving further treatment, the median number of previous lines of treatment was 4.5 (range 2–12), including autologous stem cell transplantation in 31 (91%) patients. 13 (37%) patients were penta-refractory. The most frequently used treatment options were IMID/dexamethasone treatment in 11 (32%) patients, followed by PI/dexamethasone in 10 (29%) patients. 21 (62%) patients received two or more additional lines of therapy. The median PFS was 6.6 months (range 0–36.6 months), the median TTNT was 7.5 months (range 1.4–24.5 months) and the median OS was 13.5 months, (range 0.1–38 months) for the first subsequent treatment. The overall response rate (ORR) to the first subsequent treatment was 41%, with a median duration of the response of 5 months (range 1–37 months). 12% of the patients achieved VGPR or better, with a median duration of response of 8 months (range 3–37 months).

Conclusions

Myeloma patients refractory after at least three lines of anti-CD38/PI/IMID treatment have a poor prognosis with a PFS of 6.6 months and OS of 13.5 months. These data may serve as reference to compare the potential benefit of CAR-T treatment in this group of myeloma patients when available in the near future.

Extramedullary Disease in Multiple Myeloma

PURPOSE OF REVIEW

Extramedullary disease (EMD) is a rare but recognized manifestation of multiple myeloma (MM), characterized by involvement of several organs including skin, liver, lymphatic system, pleura, and central nervous system. The incidence is about 3-5% in newly diagnosed MM patients, but has been reported in up to 20% patients in the relapsed MM setting.

RECENT FINDINGS

Presence of EMD has been associated with more aggressive phenotype of MM, elevated serum lactate dehydrogenase (LDH) enzyme, and high-risk cytogenetics [deletion 17p, translocation (4;14), translocation (14;16)]. There are several hypotheses of how EMD occurs, including factors leading to bone marrow emancipation and hematogenous spread. The treatment schema usually follows that of high-risk MM. The current review summarizes the disease characterization data, along with available data on clinical activity of available anti-MM agents for this entity.

Pomalidomide and dexamethasone in myelomatous pleural effusion

Myelomatous pleural effusion (MPE) is an uncommon clinical entity and occurs in less than 1% of all patients with multiple myeloma. MPE indicates a progression of disease, therefore is associated with a poor prognosis and estimated median survival of <3 months. Treatment of MPE is challenging, and the data regarding the role of novel agents lack in the literature. Herein, we report a relapsed IgA myeloma case of a patient presenting with MPE, who was treated with pomalidomide with a very good partial response.

Comparison of CD38-Targeted α- Versus β-Radionuclide Therapy of Disseminated Multiple Myeloma in an Animal Model

Targeted therapies for multiple myeloma (MM) include the anti-CD38 antibody daratumumab, which, in addition to its inherent cytotoxicity, can be radiolabeled with tracers for imaging and with β- and α-emitter radionuclides for radioimmunotherapy. Methods: We have compared the potential therapeutic efficacy of β- versus α-emitter radioimmunotherapy using radiolabeled DOTA-daratumumab in a preclinical model of disseminated multiple myeloma. Multiple dose levels were investigated to find the dose with the highest efficacy and lowest toxicity. Results: In a dose–response study with the β-emitter 177Lu-DOTA-daratumumab, the lowest tested dose, 1.85 MBq, extended survival from 37 to 47 d but did not delay tumor growth. Doses of 3.7 and 7.4 MBq extended survival to 55 and 58 d, respectively, causing a small equivalent delay in tumor growth, followed by regrowth. The higher dose, 11.1 MBq, eradicated the tumor but had no effect on survival compared with untreated controls, because of whole-body toxicity. In contrast, the α-emitter 225Ac-DOTA-daratumumab had a dose-dependent effect, in which 0.925, 1.85, and 3.7 kBq increased survival, compared with untreated controls (35 d), to 47, 52, and 73 d, respectively, with a significant delay in tumor growth for all 3 doses. Higher doses of 11.1 and 22.2 kBq resulted in equivalent survival to 82 d but with significant whole-body toxicity. Parallel studies with untargeted 225Ac-DOTA-trastuzumab conferred no improvement over untreated controls and resulted in whole-body toxicity. Conclusion: We conclude, and mathematic modeling confirms, that maximal biologic doses were achieved by targeted α-therapy and demonstrated 225Ac to be superior to 177Lu in delaying tumor growth and decreasing whole-body toxicity.

Single-agent belantamab mafodotin for relapsed/refractory multiple myeloma: analysis of the lyophilised presentation cohort from the pivotal DREAMM-2 study

DREAMM-2 (NCT03525678) is an ongoing global, open-label, phase 2 study of single-agent belantamab mafodotin (belamaf; GSK2857916), a B-cell maturation antigen-targeting antibody-drug conjugate, in a frozen-liquid presentation in patients with relapsed/refractory multiple myeloma (RRMM). Alongside the main study, following identical inclusion/exclusion criteria, a separate patient cohort was enrolled to receive belamaf in a lyophilised presentation (3.4 mg/kg, every 3 weeks) until disease progression/unacceptable toxicity. Primary outcome was independent review committee-assessed overall response rate (ORR). Twenty-five patients were enrolled; 24 received ≥1 dose of belamaf. As of 31 January 2020, ORR was 52% (95% CI: 31.3–72.2); 24% of patients achieved very good partial response. Median duration of response was 9.0 months (2.8–not reached [NR]); median progression-free survival was 5.7 months (2.2–9.7); median overall survival was not reached (8.7 months–NR). Most common grade 3/4 adverse events were keratopathy (microcyst-like corneal epithelial changes, a pathological finding seen on eye examination [75%]), thrombocytopenia (21%), anaemia (17%), hypercalcaemia and hypophosphatemia (both 13%), neutropenia and blurred vision (both 8%). Pharmacokinetics supported comparability of frozen-liquid and lyophilised presentations. Single-agent belamaf in a lyophilised presentation (intended for future use) showed a deep and durable clinical response and acceptable safety profile in patients with heavily pre-treated RRMM.

Outcomes of Daratumumab, Pomalidomide, and Dexamethasone, Followed by High-dose Chemotherapy and Autologous Stem Cell Transplantation, in Patients With Relapsed/Refractory Multiple Myeloma

BACKGROUND

The number of therapeutic options for patients with relapsed/refractory multiple myeloma (RRMM) has increased significantly. Our institute treated a series of patients with RRMM using DPd (daratumumab, pomalidomide, dexamethasone) as salvage therapy, followed by high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT).

PATIENTS AND METHODS

We treated 18 patients with RRMM from May 2016 to April 2020, with DPd as salvage therapy, followed by HDCT and ASCT. DPd was administered as daratumumab 16 mg/kg weekly for cycles 1 and 2, every 2 weeks for cycles 3 to 6, and then every 4 weeks. Pomalidomide was given at 4 mg orally on days 1 to 21 of a 28-day cycle, and dexamethasone at 20 or 40 mg weekly.

RESULTS

The patients had received a median of 2 (range, 1-4) previous regimens. Of the 18 patients, 13 (72%) had received ASCT before this treatment. In addition, 78% had disease refractory to proteasome inhibitors, 78% refractory to immunomodulatory agents, and 72% double refractory to immunomodulatory agents and proteasome inhibitors. The overall response rate after salvage treatment with DPd was 100% and at day 100 after ASCT was 100%; 67% had achieved a complete response or better and 78% had achieved a very good partial response or better. No treatment-related mortality had occurred by day 100. The 2-year progression-free and overall survival rates were 83.3% and 94.4%, respectively. The most common grade ≥ 3 adverse events were thrombocytopenia (100%), neutropenia (100%), and neutropenic fever (67%).

CONCLUSIONS

DPd as salvage therapy, followed by HDCT and ASCT, demonstrated deep, durable, and clinically meaningful responses with a manageable safety profile in patients with RRMM.

Novel Approaches to Improve Myeloma Cell Killing by Monoclonal Antibodies

The monoclonal antibodies (mAbs) have significantly changed the treatment of multiple myeloma (MM) patients. However, despite their introduction, MM remains an incurable disease. The mAbs currently used for MM treatment were developed with different mechanisms of action able to target antigens, such as cluster of differentiation 38 (CD38) and SLAM family member 7 (SLAMF7) expressed by both, MM cells and the immune microenvironment cells. In this review, we focused on the mechanisms of action of the main mAbs approved for the therapy of MM, and on the possible novel approaches to improve MM cell killing by mAbs. Actually, the combination of anti-CD38 or anti-SLAMF7 mAbs with the immunomodulatory drugs significantly improved the clinical effect in MM patients. On the other hand, pre-clinical evidence indicates that different approaches may increase the efficacy of mAbs. The use of trans-retinoic acid, the cyclophosphamide or the combination of anti-CD47 and anti-CD137 mAbs have given the rationale to design these types of combinations therapies in MM patients in the future. In conclusion, a better understanding of the mechanism of action of the mAbs will allow us to develop novel therapeutic approaches to improve their response rate and to overcome their resistance in MM patients.

Daratumumab therapy for relapsed or refractory multiple myeloma: a single-center retrospective study

BACKGROUND

Significant advancements have been achieved in the quality of treatment for relapsed/refractory multiple myeloma (RRMM). Currently, daratumumab (DARA) is a highly effective drug widely used for RRMM; however, the knowledge on its efficacy and safety in Japanese patients remains limited. Accordingly, we aimed to evaluate the efficacy and safety of DARA therapy for RRMM.

METHODS

We reviewed the medical records of patients who received DARA combination therapy and evaluated its efficacy and safety in our hospital.

RESULTS

DARA was administered to 44 patients between October 2017 and March 2019. The median number of previous therapies was three (range 1-9). The rates of ≥ complete response and overall response were 27.3% and 61.4%, respectively. The median progression-free survival (PFS) duration was 12.3 months [95% confidence interval (CI) 5.1 to not reached (NR)] and estimated 2-year overall survival rate was 63.7% (95% CI 46.9-76.5%). In the multivariate analysis, patients with ≥ three previous lines of therapy and mass lesions showed significantly shorter PFS durations. The observed grade 3/4 adverse events (≥ 10%) included neutropenia (59.0%), thrombocytopenia (29.5%), anemia (36.4%), lymphopenia (38.6%) and febrile neutropenia (18.2%). None of the patients discontinued DARA therapy in spite of these AEs.

CONCLUSION

DARA is an effective treatment option for most patients and is tolerable. However, patients with heavy treatment before DARA therapy and mass lesions are likely to show poorer outcomes. Our findings suggest the use of DARA therapy early in the course of the disease.

Selinexor: a first-in-class SINE compound for treatment of relapsed refractory multiple myeloma

The progression of multiple myeloma is accompanied by complex cytogenetic and epigenetic alterations that include mutation or functional inactivation of tumor suppressor proteins and overexpression of oncoproteins. Patients whose myeloma is refractory to the three major classes of drugs including immunomodulatory agents, proteasome inhibitors and anti-CD38 monoclonal antibodies have a very poor prognosis. Drugs with novel mechanisms of action that can bypass resistance mechanisms are sorely needed for this group of patients. Selinexor represents a novel, oral agent with an innovative mechanism of action that offers a significant therapeutic advance in this group of heavily treated patients. Moreover, this novel mechanism may provide additional options for patients with less refractory disease.

US Budget Impact Model for Selinexor in Relapsed or Refractory Multiple Myeloma

Objective

To estimate the budgetary impact of adopting selinexor (XPOVIO; Karyopharm Therapeutics, Inc.) for the treatment of adult patients with penta-refractory multiple myeloma (MM) from the perspective of a third-party payer in the United States (US).

Methods

A budget impact analysis was conducted in one-year increments for the first 3 years after the introduction of selinexor for a private payer or Medicare Part D. Total annual treatment costs (2018 US dollars) were calculated as the sum of drug costs, costs of adverse events (AEs; grade ≥3), along with ongoing best supportive care costs. The number of eligible patients was derived from national epidemiology statistics, healthcare databases, and published literature.

Results

In the base-case analysis, selinexor was associated with a per member per month (PMPM) cost of $0.0103 in year 3, assuming a market uptake of 64%, for a hypothetical private payer plan with one million members and four eligible patients. In a scenario analysis with 16 eligible patients with triple-class refractory MM regardless of the line of therapy (this additional scenario analysis was performed with an eligible population that does not fit squarely within the approved label for selinexor but was performed strictly for the purpose of demonstrating the results of the budget impact model when based on a larger pool of eligible patients), the estimated PMPM cost in year 3 was $0.0388. The model showed comparable sensitivity to treatment duration, wholesale acquisition cost for selinexor, and year 1 uptake. The base-case analysis conducted from the perspective of Medicare Part D was associated with a PMPM cost of $0.0078 in year 3 with 159 eligible patients.

Conclusions

The model estimates a small and manageable budget impact of adopting selinexor into a third-party US payer plan, given the low prevalence of penta-refractory MM.

ImmunoPET in Multiple Myeloma-What? So What? Now What?

Despite constant progress over the past three decades, multiple myeloma (MM) is still an incurable disease, and the identification of new biomarkers to better select patients and adapt therapy is more relevant than ever. Recently, the introduction of therapeutic monoclonal antibodies (mAbs) (including direct-targeting mAbs and immune checkpoint inhibitors) appears to have changed the paradigm of MM management, emphasizing the opportunity to cure MM patients through an immunotherapeutic approach. In this context, immuno-positron emission tomography (immunoPET), combining the high sensitivity and resolution of a PET camera with the specificity of a radiolabelled mAb, holds the capability to cement this new treatment paradigm for MM patients. It has the potential to non-invasively monitor the distribution of therapeutic antibodies or directly monitor biomarkers on MM cells, and to allow direct observation of potential changes over time and in response to various therapeutic interventions. Tumor response could, in the future, be anticipated more effectively to provide individualized treatment plans tailored to patients according to their unique imaging signatures. This work explores the important role played by immunotherapeutics in the management of MM, and focuses on some of the challenges for this drug class and the significant interest of companion imaging agents such as immunoPET.

Daratumumab induces mechanisms of immune activation through CD38+ NK cell targeting

Daratumumab (Dara), a multiple myeloma (MM) therapy, is an antibody against the surface receptor CD38, which is expressed not only on plasma cells but also on NK cells and monocytes. Correlative data have highlighted the immune-modulatory role of Dara, despite the paradoxical observation that Dara regimens decrease the frequency of total NK cells. Here we show that, despite this reduction, NK cells play a pivotal role in Dara anti-MM activity. CD38 on NK cells is essential for Dara-induced immune modulation, and its expression is restricted to NK cells with effector function. We also show that Dara induces rapid CD38 protein degradation associated with NK cell activation, leaving an activated CD38-negative NK cell population. CD38+ NK cell targeting by Dara also promotes monocyte activation, inducing an increase in T cell costimulatory molecules (CD86/80) and enhancing anti-MM phagocytosis activity ex-vivo and in vivo. In support of Dara’s immunomodulating role, we show that MM patients that discontinued Dara therapy because of progression maintain targetable unmutated surface CD38 expression on their MM cells, but retain effector cells with impaired cellular immune function. In summary, we report that CD38+ NK cells may be an unexplored therapeutic target for priming the immune system of MM patients.

Selinexor for the treatment of multiple myeloma

Introduction: Despite unprecedented advances in the treatment of multiple myeloma (MM), almost all patients develop a disease that is resistant to the five most commonly used and active anti-MM agents. The prognosis for this patient population is particularly poor resulting in an unmet need for additional therapeutic options. Exportin-1 (XPO-1) is a major nuclear export protein of macromolecular cargo frequently overexpressed in MM. Selinexor is a first-in-class, oral Selective-Inhibitor-of-Nuclear-Export (SINE) compound that impedes XPO-1. Based on results of the STORM-trial, selinexor in combination with dexamethasone was granted accelerated FDA approval for patients with penta-refractory MM in July 2019.Areas covered: This article summarizes our up-to-date knowledge on the pathophysiologic role of XPO-1 in MM. Furthermore, it reviews the most recent clinical data on selinexor in combination with dexamethasone and other anti-MM agents; and discusses its safety profile, management strategies; and potential future developments.Expert opinion: Selinexor represents a next-generation-novel agent with an innovative mechanism of action that marks a significant advance in the treatment of heavily pretreated MM patients. Ongoing studies investigate its therapeutic potential also in earlier lines of therapy. Additional data is needed to confirm that selinexor and other SINE compounds are a valuable addition to our current therapeutic armamentarium.

Use of KRD-PACE as Salvage Therapy in Aggressive, Relapsed/Bortezomib-Refractory Extramedullary Multiple Myeloma: A Report of Two Cases and Literature Review

Extramedullary multiple myeloma is defined by the presence of plasma cell infiltration outside of the bone marrow. It is associated with a poor prognosis and resistance to therapy and is often associated with high-risk cytogenetics. Aggressive relapsed and refractory extramedullary multiple myeloma is often treated with salvage infusional chemotherapy to achieve rapid disease control. Commonly used regimens include DCEP, CVAD, and VTD-PACE. While VTD-PACE contains bortezomib and thalidomide which have potent antimyeloma activity, the advent of novel agent therapy with proteasome inhibitors and immunomodulatory agents being used in the first-line setting has resulted in many patients being refractory to bortezomib by the time they are treated with VTD-PACE. Herein, we discuss two cases of aggressive relapsed, high-risk, bortezomib-refractory extramedullary multiple myeloma treated with KRD-PACE and review the available clinical data on salvage chemotherapy regimens used in relapsed refractory myeloma.

The CD38low natural killer cell line KHYG1 transiently expressing CD16F158V in combination with daratumumab targets multiple myeloma cells with minimal effector NK cell fratricide

Multiple myeloma (MM) is a clonal plasma cell malignancy typically associated with the high and uniform expression of the CD38 transmembrane glycoprotein. Daratumumab is a humanized IgG1κ CD38 monoclonal antibody (MoAb) which has demonstrated impressive single agent activity even in relapsed refractory MM patients as well as strong synergy with other anti-MM drugs. Natural Killer (NK) cells are cytotoxic immune effector cells that mediate in vivo tumour immunosurveillance. NK cells also play an important role during MoAb therapy by inducing antibody dependent cellular cytotoxicity (ADCC) via their FcγRIII (CD16) receptor. Furthermore, 15% of the population express a naturally occurring variant of CD16 harbouring a single-point polymorphism (F158V). However, the contribution of NK cells to the efficacy of daratumumab remains debatable as clinical data clearly indicate the rapid depletion of CD38^high peripheral blood NK cells in patients upon daratumumab administration. In contrast, CD38^low peripheral blood NK cells have been shown to survive daratumumab mediated fratricide in vivo, while still retaining their potent anti-MM cytolytic effector functions ex vivo. Therefore, we hypothesize that transiently expressing the CD16^F158V receptor using a "safe" mRNA electroporation-based approach on CD38^low NK cells in combination with daratumumab could represent a novel therapeutic option for treatment of MM. In the present study, we investigate a NK cell line (KHYG-1), derived from a patient with aggressive NK cell leukemia, as a platform for generating CD38^low NK cells expressing CD16^F158V which can be administered as an "off-the-shelf" therapy to target both CD38^high and CD38^low tumour clones in patients receiving daratumumab.