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

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

Minimal Residual Disease Status in Multiple Myeloma 1 Year After Autologous Hematopoietic Cell Transplantation and Lenalidomide Maintenance Are Associated With Long-Term Overall Survival

PURPOSE

Prognostic Immunophenotyping in Myeloma Response (PRIMeR) is an ancillary study of minimal residual disease (MRD) assessment for multiple myeloma by next-generation multiparameter flow cytometry (MFC). Patients were enrolled on a three-arm randomized control trial (Blood and Marrow Transplants Clinical Trials Network 0702 Stem Cell Transplant for Myeloma in Combination of Novel Agents [STaMINA]; ClinicalTrials.gov identifier: NCT01109004).

METHODS

Four hundred and thirty-five patients consented to the MRD panel, which included 10 monoclonal antibodies measured via six-color MFC. MRD was measured at baseline/preautologous hematopoietic cell transplant (BL/preAutoHCT), premaintenance (PM), and 1 year (Y1) after AutoHCT with a sensitivity of 10-5 to 10-6. The primary objective was to assess MRD-negative (MRDneg) at 1 year after AutoHCT and progression-free survival and overall survival (PFS/OS).

RESULTS

Similar to the STaMINA results, at a median follow-up of 70 months, there was no significant difference in PFS/OS by treatment arm in the PRIMeR patients. MRDneg at all three time points was associated with significantly improved PFS, and MRDneg at Y1 had significantly longer OS. Multivariate analysis of PFS, adjusting for disease risk and treatment arm, demonstrated hazard ratios (HRs) in MRD-positive patients compared with MRDneg patients at BL, PM, and Y1 of 1.55 (P = .0074), 1.83 (P = .0007), and 3.61 (P < .0001), respectively. Corresponding HRs for OS were 1.19 (P = .48), 0.88 (P = .68), and 3.36 (P < .001). Patients with sustained MRDneg or who converted to MRDneg by Y1 had similar PFS/OS.

CONCLUSION

To our knowledge, this first, prospective US cooperative group, multicenter study demonstrates that MRDneg at Y1 after AutoHCT with lenalidomide maintenance is prognostic for improved 6-year PFS and OS. Serial MRD measurements may direct trials to test how further therapy may improve long-term PFS and OS.

T cell lymphoma and secondary primary malignancy risk after commercial CAR T cell therapy

We report a T cell lymphoma (TCL) occurring 3 months after anti-CD19 chimeric antigen receptor (CAR) T cell immunotherapy for non-Hodgkin B cell lymphoma. The TCL was diagnosed from a thoracic lymph node upon surgery for lung cancer. The TCL exhibited CD8+ cytotoxic phenotype and a JAK3 variant, while the CAR transgene was very low. The T cell clone was identified at low levels in the blood before CAR T infusion and in lung cancer. To assess the overall risk of secondary primary malignancy after commercial CAR T (CD19, BCMA), we analyzed 449 patients treated at the University of Pennsylvania. At a median follow-up of 10.3 months, 16 patients (3.6%) had a secondary primary malignancy. The median onset time was 26.4 and 9.7 months for solid and hematological malignancies, respectively. The projected 5-year cumulative incidence is 15.2% for solid and 2.3% for hematological malignancies. Overall, one case of TCL was observed, suggesting a low risk of TCL after CAR T.

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

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

Exploiting the CD200-CD200R immune checkpoint axis in multiple myeloma to enhance CAR T-cell therapy

ABSTRACT

Patients with multiple myeloma (MM) treated with B-cell maturation antigen (BCMA)-specific chimeric antigen receptor (CAR) T cells usually relapse with BCMA+ disease, indicative of CAR T-cell suppression. CD200 is an immune checkpoint that is overexpressed on aberrant plasma cells (aPCs) in MM and is an independent negative prognostic factor for survival. However, CD200 is not present on MM cell lines, a potential limitation of current preclinical models. We engineered MM cell lines to express CD200 at levels equivalent to those found on aPCs in MM and show that these are sufficient to suppress clinical-stage CAR T-cells targeting BCMA or the Tn glycoform of mucin 1 (TnMUC1), costimulated by 4-1BB and CD2, respectively. To prevent CD200-mediated suppression of CAR T cells, we compared CRISPR-Cas9-mediated knockout of the CD200 receptor (CD200RKO), to coexpression of versions of the CD200 receptor that were nonsignaling, that is, dominant negative (CD200RDN), or that leveraged the CD200 signal to provide CD28 costimulation (CD200R-CD28 switch). We found that the CD200R-CD28 switch potently enhanced the polyfunctionality of CAR T cells, and improved cytotoxicity, proliferative capacity, CAR T-cell metabolism, and performance in a chronic antigen exposure assay. CD200RDN provided modest benefits, but surprisingly, the CD200RKO was detrimental to CAR T-cell activity, adversely affecting CAR T-cell metabolism. These patterns held up in murine xenograft models of plasmacytoma, and disseminated bone marrow predominant disease. Our findings underscore the importance of CD200-mediated immune suppression in CAR T-cell therapy of MM, and highlight a promising approach to enhance such therapies by leveraging CD200 expression on aPCs to provide costimulation via a CD200R-CD28 switch.

Anti-BCMA/CD19 CAR T Cells with Early Immunomodulatory Maintenance for Multiple Myeloma Responding to Initial or Later-Line Therapy

We conducted a phase I clinical trial of anti-BCMA chimeric antigen receptor T cells (CART-BCMA) with or without anti-CD19 CAR T cells (huCART19) in multiple myeloma (MM) patients responding to third- or later-line therapy (phase A, N = 10) or high-risk patients responding to first-line therapy (phase B, N = 20), followed by early lenalidomide or pomalidomide maintenance. We observed no high-grade cytokine release syndrome (CRS) and only one instance of low-grade neurologic toxicity. Among 15 subjects with measurable disease, 10 exhibited partial response (PR) or better; among 26 subjects responding to prior therapy, 9 improved their response category and 4 converted to minimal residual disease (MRD)-negative complete response/stringent complete response. Early maintenance therapy was safe, feasible, and coincided in some patients with CAR T-cell reexpansion and late-onset, durable clinical response. Outcomes with CART-BCMA + huCART19 were similar to CART-BCMA alone. Collectively, our results demonstrate favorable safety, pharmacokinetics, and antimyeloma activity of dual-target CAR T-cell therapy in early lines of MM treatment.

SIGNIFICANCE

CAR T cells in early lines of MM therapy could be safer and more effective than in the advanced setting, where prior studies have focused. We evaluated the safety, pharmacokinetics, and efficacy of CAR T cells in patients with low disease burden, responding to current therapy, combined with standard maintenance therapy. This article is highlighted in the In This Issue feature, p. 101.

S100A8/S100A9 Promote Progression of Multiple Myeloma via Expansion of Megakaryocytes

Multiple myeloma is characterized by clonal proliferation of plasma cells that accumulate preferentially in the bone marrow (BM). The tumor microenvironment is one of the leading factors that promote tumor progression. Neutrophils and monocytes are a major part of the BM tumor microenvironment, but the mechanism of their contribution to multiple myeloma progression remains unclear. Here, we describe a novel mechanism by which S100A8/S100A9 proteins produced by BM neutrophils and monocytes promote the expansion of megakaryocytes supporting multiple myeloma progression. S100A8/S100A9 alone was not sufficient to drive megakaryopoiesis but markedly enhanced the effect of thrombopoietin, an effect that was mediated by Toll-like receptor 4 and activation of the STAT5 transcription factor. Targeting S100A9 with tasquinimod as a single agent and in combination with lenalidomide and with proteasome inhibitors has potent antimyeloma effect that is at least partly independent of the adaptive immune system. This newly identified axis of signaling involving myeloid cells and megakaryocytes may provide a new avenue for therapeutic targeting in multiple myeloma.

Significance

We identified a novel mechanism by which myeloid cells promote myeloma progression independently of the adaptive immune system. Specifically, we discovered a novel role of S100A8/S100A9, the most abundant proteins produced by neutrophils and monocytes, in regulation of myeloma progression via promotion of the megakaryocyte expansion and angiogenesis. Tasquinimod, an inhibitor of S100A9, has potent antimyeloma effects as a single agent and in combination with lenalidomide and with proteasome inhibitors.

Progressive multifocal leukoencephalopathy in multiple myeloma

Progressive multifocal leukoencephalopathy (PML) is a rare and often fatal demyelinating disease of the central nervous system caused by reactivation of the JC virus in the context of immune suppression such as HIV, malignancy, and certain immunomodulatory medications. PML has been reported only rarely in multiple myeloma patients, and its presenting features and natural history in this population are not well known. We describe six cases of PML among multiple myeloma patients treated at our institution between 2013 and 2022, including two that developed on or shortly after treatment with recently developed BCMA-directed immunotherapies.

A Phase I/II Open-Label Study of Molibresib for the Treatment of Relapsed/Refractory Hematologic Malignancies

PURPOSE

Molibresib is a selective, small molecule inhibitor of the bromodomain and extra-terminal (BET) protein family. This was an open-label, two-part, Phase I/II study investigating molibresib monotherapy for the treatment of hematological malignancies (NCT01943851).

PATIENTS AND METHODS

Part 1 (dose escalation) determined the recommended Phase 2 dose (RP2D) of molibresib in patients with acute myeloid leukemia (AML), Non-Hodgkin lymphoma (NHL), or multiple myeloma. Part 2 (dose expansion) investigated the safety and efficacy of molibresib at the RP2D in patients with relapsed/refractory myelodysplastic syndrome (MDS; as well as AML evolved from antecedent MDS) or cutaneous T-cell lymphoma (CTCL). The primary endpoint in Part 1 was safety and the primary endpoint in Part 2 was objective response rate (ORR).

RESULTS

There were 111 patients enrolled (87 in Part 1, 24 in Part 2). Molibresib RP2Ds of 75 mg daily (for MDS) and 60 mg daily (for CTCL) were selected. Most common Grade 3+ adverse events included thrombocytopenia (37%), anemia (15%), and febrile neutropenia (15%). Six patients achieved complete responses [3 in Part 1 (2 AML, 1 NHL), 3 in Part 2 (MDS)], and 7 patients achieved partial responses [6 in Part 1 (4 AML, 2 NHL), 1 in Part 2 (MDS)]. The ORRs for Part 1, Part 2, and the total study population were 10% [95% confidence interval (CI), 4.8-18.7], 25% (95% CI, 7.3-52.4), and 13% (95% CI, 6.9-20.6), respectively.

CONCLUSIONS

While antitumor activity was observed with molibresib, use was limited by gastrointestinal and thrombocytopenia toxicities. Investigations of molibresib as part of combination regimens may be warranted.

A novel selective inhibitor JBI-589 targets PAD4-mediated neutrophil migration to suppress tumor progression

Neutrophils are closely involved in the regulation of tumor progression and formation of pre-metastatic niches. However, the mechanisms of their involvement and therapeutic regulation of these processes remain elusive. Here, we report a critical role of neutrophil peptidylarginine deiminase 4 (PAD4) in neutrophil migration in cancer. In several transplantable and genetically engineered mouse models, tumor growth was accompanied by significantly elevated enzymatic activity of neutrophil PAD4. Targeted deletion of PAD4 in neutrophils markedly decreased the intratumoral abundance of neutrophils and led to delayed growth of primary tumors and dramatically reduced lung metastases. PAD4 mediated neutrophil accumulation by regulating the expression of the major chemokine receptor CXCR2. PAD4 expression and activity as well as CXCR2 expression were significantly upregulated in neutrophils from patients with lung and colon cancers compared to healthy donors, and PAD4 and CXCR2 expression were positively correlated in neutrophils from cancer patients. In tumor-bearing mice, pharmacological inhibition of PAD4 with the novel PAD4 isoform-selective small molecule inhibitor JBI-589 resulted in reduced CXCR2 expression and blocked neutrophil chemotaxis. In mouse tumor models, targeted deletion of PAD4 in neutrophils or pharmacological inhibition of PAD4 with JBI-589 reduced both primary tumor growth and lung metastases and substantially enhanced the effect of immune checkpoint inhibitors. Taken together, these results suggest a therapeutic potential of targeting PAD4 in cancer.

Femtomolar SARS-CoV-2 Antigen Detection Using the Microbubbling Digital Assay with Smartphone Readout Enables Antigen Burden Quantitation and Tracking

BACKGROUND

High-sensitivity severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen assays are desirable to mitigate false negative results. Limited data are available to quantify and track SARS-CoV-2 antigen burden in respiratory samples from different populations.

METHODS

We developed the Microbubbling SARS-CoV-2 Antigen Assay (MSAA) with smartphone readout, with a limit of detection of 0.5 pg/mL (10.6 fmol/L) nucleocapsid antigen or 4000 copies/mL inactivated SARS-CoV-2 virus in nasopharyngeal (NP) swabs. We developed a computer vision and machine learning-based automatic microbubble image classifier to accurately identify positives and negatives and quantified and tracked antigen dynamics in intensive care unit coronavirus disease 2019 (COVID-19) inpatients and immunocompromised COVID-19 patients.

RESULTS

Compared to qualitative reverse transcription-polymerase chain reaction methods, the MSAA demonstrated a positive percentage agreement of 97% (95% CI 92%-99%) and a negative percentage agreement of 97% (95% CI 94%-100%) in a clinical validation study with 372 residual clinical NP swabs. In immunocompetent individuals, the antigen positivity rate in swabs decreased as days-after-symptom-onset increased, despite persistent nucleic acid positivity. Antigen was detected for longer and variable periods of time in immunocompromised patients with hematologic malignancies. Total microbubble volume, a quantitative marker of antigen burden, correlated inversely with cycle threshold values and days-after-symptom-onset. Viral sequence variations were detected in patients with long duration of high antigen burden.

CONCLUSIONS

The MSAA enables sensitive and specific detection of acute infections and quantification and tracking of antigen burden and may serve as a screening method in longitudinal studies to identify patients who are likely experiencing active rounds of ongoing replication and warrant close viral sequence monitoring.

MASS-FIX versus standard methods to predict for PFS and OS among multiple myeloma patients participating on the STAMINA trial

8009

Background: Measuring response among patients with multiple myeloma is essential for the care of patients. Deeper responses have been associated with better progression free survival (PFS) and overall survival (OS). Serum (SIFE) and urine immunofixation are the currently used markers for biochemical documentation of CR after which marrow is tested for plasma cell clearance. Next generation flow cytometry and sequencing are used to document the presence of minimal residual disease (MRD). Mass spectrometry of blood by MALDI (Mass-Fix) is a new simple, inexpensive, sensitive, and specific means of detecting monoclonal immunoglobulins. To better test the hypothesis that Mass-Fix is superior to existing methodologies to predict for survival outcomes—especially SIFE-- samples from the STAMINA trial (NCT01109004), a trial comparing 3 transplant approaches among patients who have already received induction, were employed. Methods: Five-hundred and seventy-five patients were included. Samples from enrollment post-induction (post-I) and 1-year post enrollment (1YR) were tested when available. Four response parameters were assessed univariately: Mass-Fix, SIFE, complete response, and MRD by next generation flow cytometry. Mass spectrometry spectra were evaluated in a blinded fashion. Complete response was according to the 2006 International Myeloma Working Group criteria. Multivariate Cox proportional hazard models using stepwise regression were developed to explore the independent effect of the different response parameters on PFS and OS and interactions with other risk factors. Results: Of the 4 response measures, only MRD and Mass-Fix predicted for PFS and OS at multiple testing points on multivariate analyses (Table). Of the 4 post-I measurements, only MRD predicted for PFS; however, Mass-Fix was the only post-I measurement to predict for OS. Of all the 1-year measures, both 1YR Mass-Fix and 1YR MRD positivity predicted for inferior PFS and OS. In models including MRD and Mass-Fix, SIFE and CR were not prognostic for PFS or OS. Conclusions: Mass-Fix is a powerful means to track monoclonal proteins. The full utility of Mass-Fix was not exploited given the absence of a diagnostic sample and the fact that only serum (and not urine) was tested. Despite these limitations, it performed well at pre-induction and at 1 year. Mass-Fix provides a convenient and non-invasive means of predicting for myeloma outcomes. Clinical trial information: NCT01109004. [Table: see text]

A unique window of opportunity for practical reform of cancer clinical trials

With rapid modifications in cancer clinical trial operations necessitated by the global pandemic over the last year, there is now an unprecedented opportunity to reform clinical research permanently and solidify innovative practices that have clearly been effective. On the basis of the authors' experience and recommendations from other institutions, a set of specific proposals for clinical trial reform are identified that can be implemented immediately by sponsors, regulators, and study sites. Improvements in clinical trial processes should include increased leverage of technology to facilitate remote trial activity and electronic documents, more efficient and effective communication of adverse event information, and better study design to optimize inclusion criteria, required research procedures, and data collection. The authors suggest that such reform will preserve patient safety and study integrity, address unnecessary and inefficient pre-pandemic constraints, improve access to clinical trials for patients, and speed improvements in cancer care.

Femtomolar SARS-CoV-2 Antigen Detection Using the Microbubbling Digital Assay with Smartphone Readout Enables Antigen Burden Quantitation and Dynamics Tracking

Background

Little is known about the dynamics of SARS-CoV-2 antigen burden in respiratory samples in different patient populations at different stages of infection. Current rapid antigen tests cannot quantitate and track antigen dynamics with high sensitivity and specificity in respiratory samples.

Methods

We developed and validated an ultra-sensitive SARS-CoV-2 antigen assay with smartphone readout using the Microbubbling Digital Assay previously developed by our group, which is a platform that enables highly sensitive detection and quantitation of protein biomarkers. A computer vision-based algorithm was developed for microbubble smartphone image recognition and quantitation. A machine learning-based classifier was developed to classify the smartphone images based on detected microbubbles. Using this assay, we tracked antigen dynamics in serial swab samples from COVID patients hospitalized in ICU and immunocompromised COVID patients.

Results

The limit of detection (LOD) of the Microbubbling SARS-CoV-2 Antigen Assay was 0.5 pg/mL (10.6 fM) recombinant nucleocapsid (N) antigen or 4000 copies/mL inactivated SARS-CoV-2 virus in nasopharyngeal (NP) swabs, comparable to many rRT-PCR methods. The assay had high analytical specificity towards SARS-CoV-2. Compared to EUA-approved rRT-PCR methods, the Microbubbling Antigen Assay demonstrated a positive percent agreement (PPA) of 97% (95% confidence interval (CI), 92-99%) in symptomatic individuals within 7 days of symptom onset and positive SARS-CoV-2 nucleic acid results, and a negative percent agreement (NPA) of 97% (95% CI, 94-100%) in symptomatic and asymptomatic individuals with negative nucleic acid results. Antigen positivity rate in NP swabs gradually decreased as days-after-symptom-onset increased, despite persistent nucleic acid positivity of the same samples. The computer vision and machine learning-based automatic microbubble image classifier could accurately identify positives and negatives, based on microbubble counts and sizes. Total microbubble volume, a potential marker of antigen burden, correlated inversely with Ct values and days-after-symptom-onset. Antigen was detected for longer periods of time in immunocompromised patients with hematologic malignancies, compared to immunocompetent individuals. Simultaneous detectable antigens and nucleic acids may indicate the presence of replicating viruses in patients with persistent infections.

Conclusions

The Microbubbling SARS-CoV-2 Antigen Assay enables sensitive and specific detection of acute infections, and quantitation and tracking of antigen dynamics in different patient populations at various stages of infection. With smartphone compatibility and automated image processing, the assay is well-positioned to be adapted for point-of-care diagnosis and to explore the clinical implications of antigen dynamics in future studies.

Untangling immunotactoid glomerulopathy in the MGRS era

Immunotactoid glomerulopathy (ITG) is a rare disease diagnosed by kidney biopsy showing characteristic microtubules, often in parallel arrays, in glomeruli on electron microscopy. Most cases are caused by lymphoproliferative disorders that produce monoclonal immunoglobulins that cause kidney damage, but these disorders do not meet criteria for overt malignancy. The published literature on ITG is limited. In this issue of Kidney International, 2 manuscripts provide significant insight into the clinical presentation, pathology, and treatment of ITG.

Efficacy and Safety of Hydroxychloroquine vs Placebo for Pre-exposure SARS-CoV-2 Prophylaxis Among Health Care Workers: A Randomized Clinical Trial

IMPORTANCE

Health care workers (HCWs) caring for patients with coronavirus disease 2019 (COVID-19) are at risk of exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, to our knowledge, there is no effective pharmacologic prophylaxis for individuals at risk.

OBJECTIVE

To evaluate the efficacy of hydroxychloroquine to prevent transmission of SARS-CoV-2 in hospital-based HCWs with exposure to patients with COVID-19 using a pre-exposure prophylaxis strategy.

DESIGN, SETTING, AND PARTICIPANTS

This randomized, double-blind, placebo-controlled clinical trial (the Prevention and Treatment of COVID-19 With Hydroxychloroquine Study) was conducted at 2 tertiary urban hospitals, with enrollment from April 9, 2020, to July 14, 2020; follow-up ended August 4, 2020. The trial randomized 132 full-time, hospital-based HCWs (physicians, nurses, certified nursing assistants, emergency technicians, and respiratory therapists), of whom 125 were initially asymptomatic and had negative results for SARS-CoV-2 by nasopharyngeal swab. The trial was terminated early for futility before reaching a planned enrollment of 200 participants.

INTERVENTIONS

Hydroxychloroquine, 600 mg, daily, or size-matched placebo taken orally for 8 weeks.

MAIN OUTCOMES AND MEASURES

The primary outcome was the incidence of SARS-CoV-2 infection as determined by a nasopharyngeal swab during the 8 weeks of treatment. Secondary outcomes included adverse effects, treatment discontinuation, presence of SARS-CoV-2 antibodies, frequency of QTc prolongation, and clinical outcomes for SARS-CoV-2-positive participants.

RESULTS

Of the 132 randomized participants (median age, 33 years [range, 20-66 years]; 91 women [69%]), 125 (94.7%) were evaluable for the primary outcome. There was no significant difference in infection rates in participants randomized to receive hydroxychloroquine compared with placebo (4 of 64 [6.3%] vs 4 of 61 [6.6%]; P > .99). Mild adverse events were more common in participants taking hydroxychloroquine compared with placebo (45% vs 26%; P = .04); rates of treatment discontinuation were similar in both arms (19% vs 16%; P = .81). The median change in QTc (baseline to 4-week evaluation) did not differ between arms (hydroxychloroquine: 4 milliseconds; 95% CI, -9 to 17; vs placebo: 3 milliseconds; 95% CI, -5 to 11; P = .98). Of the 8 participants with positive results for SARS-CoV-2 (6.4%), 6 developed viral symptoms; none required hospitalization, and all clinically recovered.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial, although limited by early termination, there was no clinical benefit of hydroxychloroquine administered daily for 8 weeks as pre-exposure prophylaxis in hospital-based HCWs exposed to patients with COVID-19.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04329923.

Integrated safety profile of selinexor in multiple myeloma: experience from 437 patients enrolled in clinical trials

Selinexor is an oral, small molecule inhibitor of the nuclear export protein exportin 1 with demonstrated activity in hematologic and solid malignancies. Side effects associated with selinexor include nausea, vomiting, fatigue, diarrhea, decreased appetite, weight loss, thrombocytopenia, neutropenia, and hyponatremia. We reviewed 437 patients with multiple myeloma treated with selinexor and assessed the kinetics of adverse events and impact of supportive care measures. Selinexor reduced both platelets and neutrophils over the first cycle of treatment and reached a nadir between 28 and 42 days. Platelet transfusions and thrombopoietin receptor agonists were effective at treating thrombocytopenia, and granulocyte colony stimulating factors were effective at resolving neutropenia. The onset of gastrointestinal side effects (nausea, vomiting, and diarrhea) was most common during the first 1-2 weeks of treatment. Nausea could be mitigated with 5-HT3 antagonists and either neurokinin 1 receptor antagonists, olanzapine, or cannbainoids. Loperamide and bismuth subsalicylate ameliorated diarrhea. The primary constitutional side effects of fatigue and decreased appetite could be managed with methylphenidate, megestrol, cannabinoids or olanzapine, respectively. Hyponatremia was highly responsive to sodium replacement. Selinexor has well-established adverse effects that mainly occur within the first 8 weeks of treatment, are reversible, and respond to supportive care.

Long-term follow-up of BMT CTN 0702 (STaMINA) of postautologous hematopoietic cell transplantation (autoHCT) strategies in the upfront treatment of multiple myeloma (MM)

8506

Background: STaMINA was a phase III trial comparing progression-free survival (PFS) among 758 pts randomized to: 1. second autoHCT then lenalidomide (Len) maintenance (Auto/Auto, n = 247); 2. consolidation with Len/bortezomib/ dexamethasone (RVD) followed by Len maintenance (Auto/RVD, 254); 3. Len maintenance (Auto/Len, 257). All three arms were similar (Stadtmauer JCO 2018). Len maintenance was designed to continue for 3 years and amended to allow continuation until disease progression through a follow up protocol (07LT, NCT#02322320). We report 6 yr follow up for STaMINA and the results of Len discontinuation beyond 3 years. Methods: 07LT was offered to pts who were progression-free at 38 mo; completed planned Len maintenance and were within 4 years of BMT CTN 0702 follow up. Among 431 07LT eligible patients, 273 enrolled and 179 opted to continue maintenance until disease progression. All patients enrolled in STaMINA were reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) and long-term outcomes for patients not enrolled on 07LT (N = 166) were available through this mechanism. Before combining 07LT data and CIBMTR data for LTFU analysis, outcomes in both databases were analyzed separately and confirmed to be comparable. Results: Using intent-to-treat (ITT), 6yr PFS and overall survival (OS) was the same among Auto/Auto (43.9%; 73.1%), Auto/RVD (39.7%, 74.9%) and Auto/Len (40.9%, 76.4%)(p = 0.6; p = 0.8). Protocol defined high risk disease, (HR = 1.53, p < 0.0001) and age (p = 0.03) were adverse risks for PFS. In as treated analysis, 6yr PFS were 49.4%, 39.7% and 38.6% for Auto/auto (170), Auto/RVD (222) and Auto/Len (361), respectively (p = 0.01). 6yr PFS in high risk pts as treated analysis were 43.6% and 26% for Auto/auto and Auto/Len, respectively (p = 0.03). Landmark analysis at 38 mo included 215 pts who continued Len maintenance (either on 07LT study or commercial Len) vs. 207 who stopped. Baseline demographics; study arm on 0702, induction pre-autoHCT were similar. Len discontinuation after 38 mo was associated with inferior PFS (79.5% vs. 61% at 5yr; HR = 1.91, p = 0.0004) but similar OS. Incidence of all second primary malignancies (SPM)(81 cases with 43 heme-malignancies) was associated with age. Conclusions: Long term outcomes are similar using ITT, but as treated analysis suggested a PFS benefit for tandem autoHCT, driven mainly by pts with high risk MM. Len discontinuation even at 38 mo was associated with inferior PFS. Clinical trial information: NCT02322320 .

A Novel Peptidylarginine Deiminase 4 (PAD4) Inhibitor BMS-P5 Blocks Formation of Neutrophil Extracellular Traps and Delays Progression of Multiple Myeloma

Multiple myeloma is a plasma cell malignancy, which grows in the bone marrow (BM). The major population of cells in the BM is represented by neutrophils and they can form neutrophil extracellular traps (NET). Here, we investigated whether multiple myeloma cells induce NET formation and whether targeting this process would delay multiple myeloma progression. We demonstrated that murine and human multiple myeloma cells stimulate citrullination of histone H3 and NET formation by neutrophils and that this process is abrogated by pharmacological targeting of peptidylarginine deiminase 4 (PAD4) with a novel-specific small molecule inhibitor BMS-P5. Administration of BMS-P5 to multiple myeloma-bearing mice delays appearance of symptoms and disease progression. Taken together, our data demonstrate that targeting PAD4 may be beneficial for treatment of multiple myeloma.

Oral Selinexor-Dexamethasone for Triple-Class Refractory Multiple Myeloma

BACKGROUND

Selinexor, a selective inhibitor of nuclear export compound that blocks exportin 1 (XPO1) and forces nuclear accumulation and activation of tumor suppressor proteins, inhibits nuclear factor κB, and reduces oncoprotein messenger RNA translation, is a potential novel treatment for myeloma that is refractory to current therapeutic options.

METHODS

We administered oral selinexor (80 mg) plus dexamethasone (20 mg) twice weekly to patients with myeloma who had previous exposure to bortezomib, carfilzomib, lenalidomide, pomalidomide, daratumumab, and an alkylating agent and had disease refractory to at least one proteasome inhibitor, one immunomodulatory agent, and daratumumab (triple-class refractory). The primary end point was overall response, defined as a partial response or better, with response assessed by an independent review committee. Clinical benefit, defined as a minimal response or better, was a secondary end point.

RESULTS

A total of 122 patients in the United States and Europe were included in the modified intention-to-treat population (primary analysis), and 123 were included in the safety population. The median age was 65 years, and the median number of previous regimens was 7; a total of 53% of the patients had high-risk cytogenetic abnormalities. A partial response or better was observed in 26% of patients (95% confidence interval, 19 to 35), including two stringent complete responses; 39% of patients had a minimal response or better. The median duration of response was 4.4 months, median progression-free survival was 3.7 months, and median overall survival was 8.6 months. Fatigue, nausea, and decreased appetite were common and were typically grade 1 or 2 (grade 3 events were noted in up to 25% of patients, and no grade 4 events were reported). Thrombocytopenia occurred in 73% of the patients (grade 3 in 25% and grade 4 in 33%). Thrombocytopenia led to bleeding events of grade 3 or higher in 6 patients.

CONCLUSIONS

Selinexor-dexamethasone resulted in objective treatment responses in patients with myeloma refractory to currently available therapies. (Funded by Karyopharm Therapeutics; STORM ClinicalTrials.gov number, NCT02336815.).

Prospective Study of Cardiac Events During Proteasome Inhibitor Therapy for Relapsed Multiple Myeloma

PURPOSE

Cardiovascular adverse events (CVAEs) can occur during proteasome inhibitor (PI) therapy. We conducted a prospective, observational, multi-institutional study to define risk factors and outcomes in patients with multiple myeloma (MM) receiving PIs.

PATIENTS AND METHODS

Patients with relapsed MM initiating carfilzomib- or bortezomib-based therapy underwent baseline assessments and repeated assessments at regular intervals over 6 months, including cardiac biomarkers (troponin I or T, brain natriuretic peptide [BNP], and N-terminal proBNP), ECG, and echocardiography. Monitoring occurred over 18 months for development of CVAEs.

RESULTS

Of 95 patients enrolled, 65 received carfilzomib and 30 received bortezomib, with median 25 months of follow-up. Sixty-four CVAEs occurred, with 55% grade 3 or greater in severity. CVAEs occurred in 51% of patients treated with carfilzomib and 17% of those treated with bortezomib (P = .002). Median time to first CVAE from treatment start was 31 days, and 86% occurred within the first 3 months. Patients receiving carfilzomib-based therapy with a baseline elevated BNP level higher than 100 pg/mL or N-terminal proBNP level higher than 125 pg/mL had increased risk for CVAE (odds ratio, 10.8; P < .001). Elevated natriuretic peptides occurring mid-first cycle of treatment with carfilzomib were associated with a substantially higher risk of CVAEs (odds ratio, 36.0; P < .001). Patients who experienced a CVAE had inferior progression-free survival (log-rank P = .01) and overall survival (log-rank P < .001). PI therapy was safely resumed in 89% of patients, although 41% required chemotherapy modifications.

CONCLUSION

CVAEs are common during PI therapy for relapsed MM, especially with carfilzomib, particularly within the first 3 months of therapy. CVAEs were associated with worse overall outcomes, but usually, discontinuation of therapy was not required. Natriuretic peptides were highly predictive of CVAEs; however, validation of this finding is necessary before uniform incorporation into the routine management of patients receiving carfilzomib.

Abstract 2103: NETs promote tumor resistance to anthracyclines

Multiple Myeloma (MM) is an incurable blood cancer characterized by the clonal proliferation of plasma cells that accumulate in the bone marrow (BM). Resistance to chemotherapy represents one of the main challenges in the treatment of this disease. We have previously shown that neutrophils, one of the major cellular populations in the BM, protect MM cells from chemotherapies including anthracyclines; however, the mechanisms of this effect remain unknown. Thus, we set out to investigate the mechanisms by which neutrophils reduce sensitivity of tumor cells to anthracyclines. Neutrophil extracellular traps (NETs) are structures composed of chromatin and protein formed by neutrophils that are a part of an innate immune mechanism of binding and killing pathogens. Recently, NETs have been shown to form in cancer patients as well as tumor-bearing animals and have been implicated in solid tumor progression; however, their role in hematological malignancies remain poorly understood. Utilizing an in vitro culture system, we demonstrated that MM cells were able to induce NET formation by BM neutrophils. Interestingly, neutrophils isolated from the BM of patients with MM have a significantly higher ability to produce NETs in response to tumor cells as compared to BM neutrophils from donors. NET formation was accompanied by an increase in the level of extracellular DNA. Using imaging flow cytometry and confocal microscopy we demonstrated that extracellular DNA is internalized by tumor cells and localizes to the cytoplasm. This internalized DNA was able to bind to doxorubicin and other anthracyclines thereby reducing their cytotoxic effects. Significantly increased cell-free DNA levels were detected in BM aspirates from MM patients as well as in tumor-bearing mice. Targeting the extracellular DNA in vivo using the clinically available DNase, Pulmozyme, restored the sensitivity of tumor cells to doxorubicin resulting in prolonged survival of tumor-bearing animals. Here, we have identified a novel mechanism of resistance to anthracyclines that is mediated by neutrophils in the tumor microenvironment and provided evidence to support the premise that targeting this mechanism would be of significant benefit in the treatment of MM.

Citation Format: Cindy Lin, Sarah E. Herlihy, Marina Li, Hui Deng, Luca Bernabei, Dmitry I. Gabrilovich, Dan T. Vogl, Yulia Nefedova. NETs promote tumor resistance to anthracyclines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2103.

Proteasome inhibitor associated cardiovascular adverse events: A real-world claims based study

e19534

Background: Cardiovascular adverse events (CVAE) are common in patients with multiple myeloma (MM). Recent evidence suggests higher rates of CVAE occur among patients receiving carfilzomib (CFZ) compared to other MM therapies. We sought to determine the real-world relative incidence of CVAE in patients receiving CFZ and bortezomib (BTZ). Methods: We conducted a retrospective cohort study using the Optum Clinformatics Datamart. Patients with MM were included if they received BTZ or CFZ from 2012 to 2016. Exposure periods were defined as 90 days following infusion of either drug. Cardiac hospitalizations were identified using validated ICD-9 or ICD-10 code algorithms for heart failure, arrhythmia, myocardial infarction, and hypertensive urgency. Incidence rate ratios (IRR) were calculated using Poisson regression. Results: We identified 922 patients receiving CFZ and 4092 patients receiving BTZ (median age 70 and 72; median treatment duration 99 and 107 days; concurrent immunomodulatory drugs received in 28% and 25%, respectively). Unadjusted CVAE rates are summarized below. A multivariable regression model showed age (IRR 1.43, 95% CI 1.33-1.55) and male gender (IRR 1.22, 95% CI 1.07-1.40) were independent risk factors for CVAE while concurrent IMiD prescription was associated with lower risk (IRR 0.70, 95% CI 0.58-0.85). Adjusted CVAE rates were similar for patients treated with CFZ and BTZ (IRR 1.06, 95% CI 0.89-1.27). Conclusions: We found higher rates of CVAE hospitalizations than described in clinical trials. This may reflect differences in real-world treatment, patient selection patterns, or later identification of CVAE. Further study is need to identify patients at high-risk of CVAE and to develop risk reduction strategies. [Table: see text]

Overall survival (OS) with oral selinexor plus low dose dexamethasone (Sd) in patients with triple class refractory-multiple myeloma (TCR-MM)

8014

Background: TCR-MM is defined as being refractory to immunomodulatory agents, proteasome inhibitors, and anti-CD38 mAbs, representing an urgent unmet medical need with a median OS of 3-5 months( Pick M et al, Eur J Haem 2018; Gandhi U et al, ASH 2018). Sd has shown a 26.2% overall response rate (ORR) in 122 patients (pts) with TCR-MM in the Phase 2b STORM study ( Chari A et al, ASH 2018). Here, we evaluate the OS of pts in the STORM study with Sd and in pts with bortezomib, carfilzomib, lenalidomide, pomalidomide, and daratumumab (“penta”)-exposed, TCR-MM from an observational cohort not receiving Sd. Methods: Data were drawn from STORM and a retrospective cohort from the nationally representative Flatiron Health Analytic Database (FHAD). All pts from both sources had penta-exposed TCR-MM. In order to align study populations, OS was evaluated in pts in STORM whose first therapy after their MM reached TCR status was Sd and in pts in the FHAD who received ≥1 therapy after their MM reached TCR status. The index date for this evaluation was the start date of treatment after their MM reached TCR status. A Cox proportional hazards regression model was performed to assess the survival impact of Sd. In STORM, ORR was assessed by an Independent Review Committee based on IMWG criteria. Results: In the FHAD, 69 pts with TCR-MM were identified. Characteristics of the two groups of pts were similar, except that pts in STORM were more heavily pretreated, had a higher frequency of high-risk MM, a longer time since initial diagnosis of MM, and higher baseline hemoglobin and platelet values. Among the 122 pts in STORM, 64 received Sd as their first therapy after their MM became TCR, and ORR was 32.8%. Among the 69 pts from FHAD, 37 received ≥1 therapy after their MM became TCR. Median OS (N = 64) was 10.4 months for pts receiving Sd in STORM and 5.2 months (N = 37) for pts not receiving Sd in FHAD (HR = 0.49, p = 0.0241). Conclusions: The prognosis of TCR-MM in the real-world population appears very poor. Within the limits of this analysis, median OS of pts receiving Sd as their first therapy after their MM becomes TCR is significantly better than those not receiving Sd, suggesting that Sd may be associated with an OS benefit in pts with TCR-MM. Clinical trial information: NCT02336815.

B cell maturation antigen-specific CAR T cells are clinically active in multiple myeloma

BACKGROUND

Chimeric antigen receptor (CAR) T cells are a promising therapy for hematologic malignancies. B-cell maturation antigen (BCMA) is a rational target in multiple myeloma (MM).

METHODS

We conducted a phase I study of autologous T cells lentivirally-transduced with a fully-human, BCMA-specific CAR containing CD3ζ and 4-1BB signaling domains (CART-BCMA), in subjects with relapsed/refractory MM. Twenty-five subjects were treated in 3 cohorts: 1) 1-5 x 108 CART-BCMA cells alone; 2) Cyclophosphamide (Cy) 1.5 g/m2 + 1-5 x 107 CART-BCMA cells; and 3) Cy 1.5 g/m2 + 1-5 x 108 CART-BCMA cells. No pre-specified BCMA expression level was required.

RESULTS

CART-BCMA cells were manufactured and expanded in all subjects. Toxicities included cytokine release syndrome and neurotoxicity, which were grade 3-4 in 8 (32%) and 3 (12%) subjects, respectively, and reversible. One subject died at day 24 from candidemia and progressive myeloma, following treatment for severe CRS and encephalopathy. Responses (based on treated subjects) were seen in 4/9 (44%) in cohort 1, 1/5 (20%) in cohort 2, and 7/11 (64%) in cohort 3, including 5 partial, 5 very good partial, and 2 complete responses, 3 of which were ongoing at 11, 14, and 32 months. Decreased BCMA expression on residual MM cells was noted in responders; expression increased at progression in most. Responses and CART-BCMA expansion were associated with CD4:CD8 T cell ratio and frequency of CD45RO-CD27+CD8+ T cells in the pre-manufacturing leukapheresis product.

CONCLUSION

CART-BCMA infusions with or without lymphodepleting chemotherapy are clinically active in heavily-pretreated MM patients.

TRIAL REGISTRATION

NCT02546167.

FUNDING

University of Pennsylvania-Novartis Alliance and NIH.

RUNX proteins desensitize multiple myeloma to lenalidomide via protecting IKZFs from degradation

Ikaros family zinc finger protein 1 and 3 (IKZF1 and IKZF3) are transcription factors that promote multiple myeloma (MM) proliferation. The immunomodulatory imide drug (IMiD) lenalidomide promotes myeloma cell death via Cereblon (CRBN)-dependent ubiquitylation and proteasome-dependent degradation of IKZF1 and IKZF3. Although IMiDs have been used as first-line drugs for MM, the overall survival of refractory MM patients remains poor and demands the identification of novel agents to potentiate the therapeutic effect of IMiDs. Using an unbiased screen based on mass spectrometry, we identified the Runt-related transcription factor 1 and 3 (RUNX1 and RUNX3) as interactors of IKZF1 and IKZF3. Interaction with RUNX1 and RUNX3 inhibits CRBN-dependent binding, ubiquitylation, and degradation of IKZF1 and IKZF3 upon lenalidomide treatment. Inhibition of RUNXs, via genetic ablation or a small molecule (AI-10-104), results in sensitization of myeloma cell lines and primary tumors to lenalidomide. Thus, RUNX inhibition represents a valuable therapeutic opportunity to potentiate IMiDs therapy for the treatment of multiple myeloma.

Autologous Transplantation, Consolidation, and Maintenance Therapy in Multiple Myeloma: Results of the BMT CTN 0702 Trial

PURPOSE

Single-cycle melphalan 200 mg/m² and autologous hematopoietic cell transplantation (AHCT) followed by lenalidomide (len) maintenance have improved progression-free survival (PFS) and overall survival (OS) for transplantation-eligible patients with multiple myeloma (MM). We designed a prospective, randomized, phase III study to test additional interventions to improve PFS by comparing AHCT, tandem AHCT (AHCT/AHCT), and AHCT and four subsequent cycles of len, bortezomib, and dexamethasone (RVD; AHCT + RVD), all followed by len until disease progression.

PATIENTS AND METHODS

Patients with symptomatic MM within 12 months from starting therapy and without progression who were age 70 years or younger were randomly assigned to AHCT/AHCT + len (n = 247), AHCT + RVD + len (n = 254), or AHCT + len (n = 257). The primary end point was 38-month PFS.

RESULTS

The study population had a median age of 56 years (range, 20 to 70 years); 24% of patients had high-risk MM, 73% had a triple-drug regimen as initial therapy, and 18% were in complete response at enrollment. The 38-month PFS rate was 58.5% (95% CI, 51.7% to 64.6%) for AHCT/AHCT + len, 57.8% (95% CI, 51.4% to 63.7%) for AHCT + RVD + len, and 53.9% (95% CI, 47.4% to 60%) for AHCT + len. For AHCT/AHCT + len, AHCT + RVD + len, and AHCT + len, the OS rates were 81.8% (95% CI, 76.2% to 86.2%), 85.4% (95% CI, 80.4% to 89.3%), and 83.7% (95% CI, 78.4% to 87.8%), respectively, and the complete response rates at 1 year were 50.5% (n = 192), 58.4% (n = 209), and 47.1% (n = 208), respectively. Toxicity profiles and development of second primary malignancies were similar across treatment arms.

CONCLUSION

Second AHCT or RVD consolidation as post-AHCT interventions for the up-front treatment of transplantation-eligible patients with MM did not improve PFS or OS. Single AHCT and len should remain as the standard approach for this population.

Anti-CD19 CAR T cells with high-dose melphalan and autologous stem cell transplantation for refractory multiple myeloma

BACKGROUND

Multiple myeloma is usually fatal due to serial relapses that become progressively refractory to therapy. CD19 is typically absent on the dominant multiple myeloma cell population but may be present on minor subsets with unique myeloma-propagating properties. To target myeloma-propagating cells, we clinically evaluated autologous T cells transduced with a chimeric antigen receptor (CAR) against CD19 (CTL019).

METHODS

Subjects received CTL019 following salvage high-dose melphalan and autologous stem cell transplantation (ASCT). All subjects had relapsed/refractory multiple myeloma and had previously undergone ASCT with less than 1 year progression-free survival (PFS).

RESULTS

ASCT + CTL019 was safe and feasible, with most toxicity attributable to ASCT and no severe cytokine release syndrome. Two of 10 subjects exhibited significantly longer PFS after ASCT + CTL019 compared with prior ASCT (479 vs. 181 days; 249 vs. 127 days). Correlates of favorable clinical outcome included peak CTL019 frequency in bone marrow and emergence of humoral and cellular immune responses against the stem-cell antigen Sox2. Ex vivo treatment of primary myeloma samples with a combination of CTL019 and CAR T cells against the plasma cell antigen BCMA reliably inhibited myeloma colony formation in vitro, whereas treatment with either CAR alone inhibited colony formation inconsistently.

CONCLUSION

CTL019 may improve duration of response to standard multiple myeloma therapies by targeting and precipitating secondary immune responses against myeloma-propagating cells.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT02135406.

FUNDING

Novartis, NIH, Conquer Cancer Foundation.

Selective Inhibition of Nuclear Export With Oral Selinexor for Treatment of Relapsed or Refractory Multiple Myeloma

Purpose Selinexor, a first-in-class, oral, selective exportin 1 (XPO1) inhibitor, induces apoptosis in cancer cells through nuclear retention of tumor suppressor proteins and the glucocorticoid receptor, along with inhibition of translation of oncoprotein mRNAs. We studied selinexor in combination with low-dose dexamethasone in patients with multiple myeloma refractory to the most active available agents. Patients and Methods This phase II trial evaluated selinexor 80 mg and dexamethasone 20 mg, both orally and twice weekly, in patients with myeloma refractory to bortezomib, carfilzomib, lenalidomide, and pomalidomide (quad-refractory disease), with a subset also refractory to an anti-CD38 antibody (penta-refractory disease). The primary end point was overall response rate (ORR). Results Of 79 patients, 48 had quad-refractory and 31 had penta-refractory myeloma. Patients had received a median of seven prior regimens. The ORR was 21% and was similar for patients with quad-refractory (21%) and penta-refractory (20%) disease. Among patients with high-risk cytogenetics, including t(4;14), t(14;16), and del(17p), the ORR was 35% (six of 17 patients). The median duration of response was 5 months, and 65% of responding patients were alive at 12 months. The most common grade ≥ 3 adverse events were thrombocytopenia (59%), anemia (28%), neutropenia (23%), hyponatremia (22%), leukopenia (15%), and fatigue (15%). Dose interruptions for adverse events occurred in 41 patients (52%), dose reductions occurred in 29 patients (37%), and treatment discontinuation occurred in 14 patients (18%). Conclusion The combination of selinexor and dexamethasone has an ORR of 21% in patients with heavily pretreated, refractory myeloma with limited therapeutic options.

Carfilzomib-Associated Cardiovascular Adverse Events: A Systematic Review and Meta-analysis

Importance

Cardiovascular adverse events (CVAE) with carfilzomib in patients with multiple myeloma can be potentially life-threatening and remain incompletely characterized. We performed the first systematic review and meta-analysis of carfilzomib-associated CVAE.

Objective

To determine the incidence of carfilzomib-associated CVAE and to compare the rates of carfilzomib CVAE among different doses and companion therapies.

Data Sources

PubMed, EMBASE, Web of Science, and clinicaltrials.gov were queried for the keywords "carfilzomib," "Kyprolis," and "PX-171" through January 1, 2017.

Study Selection

Phase 1 to 3 prospective clinical trials of carfilzomib in patients with multiple myeloma with evaluable toxic effects data were eligible for meta-analysis.

Data Extraction and Synthesis

Data were independently extracted by 2 reviewers following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Pooled incidence rates and relative risks (for randomized trials) and 95% confidence intervals were calculated using a random effects model. Subgroup analyses were performed to assess study-level characteristics associated with CVAE.

Main Outcomes and Measures

Cardiovascular adverse events were defined as heart failure, hypertension, ischemia, and arrhythmia. All-grade and grades 3 or higher AEs and study characteristics were recorded.

Results

A total of 514 studies were assessed for eligibility. Of those, 24 studies were eligible, including a total of 2594 patients with multiple myeloma. All-grade and grades 3 and higher CVAE were seen in 617 (18.1%) and 274 (8.2%), respectively. Phase 2 or 3 studies and carfilzomib doses of 45 mg/m2 or higher were associated with high-grade CVAE. Median age older than 65 years, prior myeloma therapies, and concurrent myeloma therapies were not associated with CVAE. For the 3 randomized clinical trials, the summary relative risk of all-grade and grade 3 or higher CVAE for patients receiving carfilzomib compared with noncarfilzomib-receiving control patients were 1.8 and 2.2, respectively.

Conclusions and Relevance

Carfilzomib was associated with a significant incidence of CVAE, with higher rates seen with higher doses of carfilzomib. Phase 1 studies may be underdetecting CVAE. Future studies are needed to identify patients at high risk for CVAE, develop optimal monitoring strategies, and explore strategies to mitigate these risks.

Long-term health-related quality of life in transplant-ineligible patients with newly diagnosed multiple myeloma receiving lenalidomide and dexamethasone

The FIRST trial demonstrated that continuous therapy with lenalidomide and dexamethasone (Rd) prolongs overall survival (OS) and improves health-related quality of life (HRQoL) during the first 18 months of therapy in newly diagnosed multiple myeloma (NDMM) patients. However, patient-reported HRQoL data were not collected after 18 months. We therefore estimated HRQoL scores based on time-varying data collected during progression-free follow-up after 18 months. During the initial 18 months of Rd, observed changes from baseline were within the 95% confidence interval of the predictive models at 33 of 35 time points across 7 HRQoL scores. Predicted scores after 18 months of therapy showed that observed HRQoL improvements during therapy were maintained or improved. Therefore, the survival gain observed with Rd does not come at a cost of declining HRQoL during continuous therapy beyond 18 months, supporting long-term Rd as a standard of care for initial myeloma therapy.

Response status as predictor of survival after autologous hematopoietic cell transplant (AHCT), without or with consolidation (with bortezomib, lenalidomide (Len) and dexamethasone) and len maintenance (AM vs. ACM) versus tandem AHCT and len maintenance (TAM) for up-front treatment of patients (pts) with multiple myeloma (MM): BMT CTN0702-stamina (NCT01109004)

8010

Background: The Stamina trial primarily aimed to identify the best strategy among AM, ACM, and TAM, leading to longer PFS (LBA-1, ASH, 2016). Here we report on interim, exploratory results of the association between PFS and overall survival (OS) and baseline MM response, risk category, and treatments (Rx). Methods: Pts with MM, < 71 years, < 12 mos from diagnosis were randomized to melphalan 200mg/m2(mel) and AHCT (AM), tandem mel AHCT (TAM), or mel AHCT and 4 cycles of RVD ((ACM). Pts received Len till progression. Pts were stratified by high risk vs. standard ( del13q, del17q, t(4;14), t(14;16), t(14;20) and hypodyploid; high β2 microglobulin). Kaplan Meier estimates of PFS and OS were performed as a function of Rx and ≥ very good partial response (VPGR including CRs) vs. < VGPR. Cox proportional hazard models explored associations between PFS or OS and risk category, Rx, and ≥ VPGR vs. < VGPR. Results: Between 6/2010-11/2013, 758 pts (AM, N = 257; ACM, N = 254; TAM, N = 247) aged 20-70 years (median 57y) were enrolled (24% high-risk). Baseline ≥VGPR responses were 45.5- 49.8%. PFS at 38 months was similar. For < VGPR, 38-mos PFS with TAM:55.8% (95%CI: 45.8%, 64.7%); ACM: 54.0% (44.7%, 62.5%); AM: 50.1% (40.6%, 58.9%); For ≥VGPR, 38-mos PFS with TAM: 57.1% (46.8%, 66.1%); ACM: 60.1% (50.1%, 68.7%); AM: 55.1% (45.1%, 64.0%). Analyzing response, risk category, and Rx revealed no association between baseline response and PFS (Baseline response < VGPR, hazard ratio (HR): 1.21,95% CI: 0.97-1.52) or OS (baseline response < VGPR, HR 1.02, 95%CI:0.70-1.48). High risk category had an adverse association for PFS (HR 1.62, 95% CI: 1.27-2.07) and OS (HR 1.51 (95% CI:1.01-2.26). Conclusions: In this analysis < VGPR at baseline was not associated with PFS or OS. High-risk had an adverse association. Whether accomplishment of CR/minimal residual disease after AM, ACM,or TAM predicts for longer PFS and OS is the subject of ongoing analysis. Clinical trial information: NCT01109004.

Carfilzomib-associated cardiovascular adverse events: A systematic review and meta-analysis

8018

Background: The incidence and nature of cardiovascular adverse events (CVAEs) with carfilzomib (CFZ) in multiple myeloma (MM) remain incompletely defined. We performed the first systematic review and meta-analysis of CFZ CVAEs. Methods: PubMed was queried for the keywords “carfilzomib,” “Kyprolis,” and “PX-171.” Phase 1-3 clinical trials of carfilzomib in MM with evaluable toxicity data were included. CVAEs were defined as heart failure, hypertension, ischemia, and arrhythmia. All-grade and grade ≥3 CVAEs and study characteristics were recorded. Summary incidence rates and relative risks (for randomized trials) with 95% confidence intervals were calculated using the logistic-normal random-effects model. Subgroup analyses were performed using study level covariates. Results: 514 studies were reviewed. 2623 MM patients from 25 eligible studies were included. Incidence rates are summarized in the table. All grade and grade ≥3 CVAEs were seen in 16.8% and 7.6 %, respectively. Phase 2 or 3 studies, carfilzomib doses ≥45mg/m2, and longer infusion length were study characteristics associated with high-grade cardiac AEs (p<0.05). Median age >65, prior MM therapies, and concurrent MM therapies were not associated with CVAEs (p>.05). For the three randomized trials, the relative risk of all-grade and grade ≥3 CVAEs were 1.75 and 2.25, respectively (p<0.001). Conclusions: CFZ is associated with a significant incidence of CVAEs, including heart failure, hypertension, ischemia, and arrhythmia. Phase I studies may be underdetecting CVAEs. Future studies are needed to: identify patients at high-risk for CVAEs, develop optimal monitoring strategies, and explore therapies to mitigate these risks. [Table: see text]

Ricolinostat, the First Selective Histone Deacetylase 6 Inhibitor, in Combination with Bortezomib and Dexamethasone for Relapsed or Refractory Multiple Myeloma

Purpose: Histone deacetylase (HDAC) inhibition improves the efficacy of proteasome inhibition for multiple myeloma but adds substantial toxicity. Preclinical models suggest that the observed synergy is due to the role of HDAC6 in mediating resistance to proteasome inhibition via the aggresome/autophagy pathway of protein degradation.Experimental Design: We conducted a phase I/II trial of the HDAC6-selective inhibitor ricolinostat to define the safety, preliminary efficacy, and recommended phase II dose in combination with standard proteasome inhibitor therapy. Patients with relapsed or refractory multiple myeloma received oral ricolinostat on days 1-5 and 8-12 of each 21-day cycle.Results: Single-agent ricolinostat therapy resulted in neither significant toxicity nor clinical responses. Combination therapy with bortezomib and dexamethasone was well-tolerated during dose escalation but led to dose-limiting diarrhea in an expansion cohort at a ricolinostat dose of 160 mg twice daily. Combination therapy at a ricolinostat dose of 160 mg daily in a second expansion cohort was well tolerated, with less severe hematologic, gastrointestinal, and constitutional toxicities compared with published data on nonselective HDAC inhibitors. The overall response rate in combination with daily ricolinostat at ≥160 mg was 37%. The response rate to combination therapy among bortezomib-refractory patients was 14%. Samples taken during therapy showed dose-dependent increases of acetylated tubulin in peripheral blood lymphocytes.Conclusions: At the recommended phase II dose of ricolinostat of 160 mg daily, the combination with bortezomib and dexamethasone is safe, well-tolerated, and active, suggesting that selective inhibition of HDAC6 is a promising approach to multiple myeloma therapy. Clin Cancer Res; 23(13); 3307-15. ©2017 AACR.

Lectin-type oxidized LDL receptor-1 distinguishes population of human polymorphonuclear myeloid-derived suppressor cells in cancer patients

Polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) are important regulators of immune responses in cancer and have been directly implicated in promotion of tumor progression. However, the heterogeneity of these cells and lack of distinct markers hampers the progress in understanding of the biology and clinical importance of these cells. Using partial enrichment of PMN-MDSC with gradient centrifugation we determined that low density PMN-MDSC and high density neutrophils from the same cancer patients had a distinct gene profile. Most prominent changes were observed in the expression of genes associated with endoplasmic reticulum (ER) stress. Surprisingly, low-density lipoprotein (LDL) was one of the most increased regulators and its receptor oxidized LDL receptor 1 OLR1 was one of the most overexpressed genes in PMN-MDSC. Lectin-type oxidized LDL receptor 1 (LOX-1) encoded by OLR1 was practically undetectable in neutrophils in peripheral blood of healthy donors, whereas 5-15% of total neutrophils in cancer patients and 15-50% of neutrophils in tumor tissues were LOX-1⁺. In contrast to their LOX-1^- counterparts, LOX-1⁺ neutrophils had gene signature, potent immune suppressive activity, up-regulation of ER stress, and other biochemical characteristics of PMN-MDSC. Moreover, induction of ER stress in neutrophils from healthy donors up-regulated LOX-1 expression and converted these cells to suppressive PMN-MDSC. Thus, we identified a specific marker of human PMN-MDSC associated with ER stress and lipid metabolism, which provides new insight to the biology and potential therapeutic targeting of these cells.

Bone marrow PMN-MDSCs and neutrophils are functionally similar in protection of multiple myeloma from chemotherapy

Multiple myeloma (MM) is an incurable cancer of plasma cells localized preferentially in the bone marrow (BM). Resistance to chemotherapy represents one of the main challenges in MM management. BM microenvironment is known to play a critical role in protection of MM cells from chemotherapeutics; however, mechanisms responsible for this effect are largely unknown. Development of MM is associated with accumulation of myeloid-derived suppressor cells (MDSCs) mostly represented by pathologically activated relatively immature polymorphonuclear neutrophils (PMN-MDSCs). Here, we investigated whether PMN-MDSCs are responsible for BM microenvironment-mediated MM chemoresistance. Using in vivo mouse models allowing manipulation of myeloid cell number, we demonstrated a critical role for myeloid cells in MM growth and chemoresistance. PMN-MDSCs isolated from MM-bearing host are immunosuppressive and thus, functionally distinct from their counterpart in tumor-free host neutrophils. We found, however, that both PMN-MDSCs and neutrophils equally promote MM survival from doxorubicin and melphalan and that this effect is mediated by soluble factors rather than direct cell-cell contact. Our data indicate that targeting PMN-MDSCs would enhance chemotherapy efficacy in MM.

Financial toxicity in insured patients with multiple myeloma: a cross-sectional pilot study

BACKGROUND

Financial toxicity is increasingly recognised as adversely affecting the quality of life and medication adherence in patients with cancer in the USA. Patients with multiple myeloma might be particularly vulnerable because of high use of novel treatments and extended treatment duration.

METHODS

Between Aug 18, 2014, and Jan 7, 2015, we did a cross-sectional survey of individuals receiving at least 3 months of ongoing treatment for multiple myeloma at a tertiary academic medical centre in the USA. The survey was derived from previous reported studies and included the 11-item COST measure (financial toxicity score range 0-44). A paper survey was offered to eligible patients on arrival for routine follow-up visits, and participants were asked to complete the survey before or after their visit to the clinic. Insurance and treatment data were obtained from patients' electronic health records.

FINDINGS

Of 111 patients approached for the study, 100 individuals completed the survey. 59 (59%) of 100 patients reported that treatment costs were higher than expected, 70 (71%) of 99 had at least minor financial burden, and 36 (36%) of 100 reported applying for financial assistance. Use of savings to pay for myeloma treatment was common (43 [46%] of 94 patients) and 21 (21%) of 98 individuals borrowed money to pay for medications. COST scores were highly correlated with patient-reported use of strategies to cope with myeloma treatment expenses. On multivariable analysis, younger age (correlation coefficient β 0·36, 95% CI 0·15 to 0·56, p=0·00092), non-married status (5·6, 1·5 to 9·6, p=0·0074), longer duration since diagnosis (-4·8, -9·3 to -0·2, p=0·042), and lower household income (US$40 000-79 999: 7·8, 2·7 to 12·9, p=0·0031; ≥$80 000: 11·8, 7·1 to 16·4, p<0·0001) were associated with higher financial burden as measured with the COST score.

INTERPRETATION

Patient-reported financial toxicity and use of coping mechanisms were common in our insured population with multiple myeloma. Additional attention to rising treatment costs and cost sharing is needed to address the increasing evidence of financial toxicity affecting patients with cancer.

FUNDING

University of Pennsylvania Perelman School of Medicine.