BCMA- or GPRC5D-targeting bispecific antibodies in multiple myeloma: efficacy, safety, and resistance mechanisms.

ABSTRACT: Bispecific antibodies that engage T cells to target B-cell maturation antigen or G-protein-coupled receptor class C group 5 member D have demonstrated remarkable efficacy in heavily pretreated relapsed or refractory multiple myeloma (MM), leading to the recent accelerated approval of teclistamab, elranatamab, and talquetamab by health agencies. Future challenges, however, remain to define their optimal dosing schedule and duration, sequencing, and integration with established anti-MM therapeutics as well as delineating the biological and clinical mediators of immune escape.

Integrated epigenetic and transcriptional single-cell analysis of t(11;14) multiple myeloma and its BCL2 dependency.

ABSTRACT: The translocation t(11;14) occurs in 20% of patients with multiple myeloma (MM) and results in the upregulation of CCND1. Nearly two-thirds of t(11;14) MM cells are BCL2 primed and highly responsive to the oral BCL2 inhibitor venetoclax. Although it is evident that this unique sensitivity to venetoclax depends on the Bcl-2 homology domain 3- proapoptotic protein priming of BCL2, the biology underlying t(11;14) MM dependency on BCL2 is poorly defined. Importantly, the epigenetic regulation of t(11;14) transcriptomes and its impact on gene regulation and clinical response to venetoclax remain elusive. In this study, by integrating assay for transposase-accessible chromatin by sequencing (ATAC-seq) and RNA-seq at the single-cell level in primary MM samples, we have defined the epigenetic regulome and transcriptome associated with t(11;14) MM. A B-cell-like epigenetic signature was enriched in t(11;14) MM, confirming its phylogeny link to B-cell rather than plasma cell biology. Of note, a loss of a B-cell-like epigenetic signature with a gain of canonical plasma cell transcription factors was observed at the time of resistance to venetoclax. In addition, MCL1 and BCL2L1 copy number gains and structural rearrangements were linked to venetoclax resistance in patients with t(11;14) MM. To date, this is the first study in which both single-cell (sc) ATAC-seq and scRNA-seq analysis are integrated into primary MM cells to obtain a deeper resolution of the epigenetic regulome and transcriptome associated with t(11;14) MM biology and venetoclax resistance.

Impact of soluble BCMA and non-T-cell factors on refractoriness to BCMA-targeting T-cell engagers in multiple myeloma.

Adoptive T cell therapy is a promising therapy for multiple myeloma (MM), but its efficacy hinges on understanding relevant biological and predictive markers of response. B cell maturation antigen (BCMA) is a key target antigen in MM, with active development of multiple anti-BCMA T cell engagers (TCE) and chimeric antigen receptor T cell (CAR T) therapies. The regulation of surface BCMA expression by MM cells, resulting in the shedding of soluble BCMA (sBCMA), has triggered debate surrounding the significance of sBCMA as a predictive marker and its potential impact on treatment outcomes. In order to address this, we leveraged whole genome sequencing and in vitro assays to demonstrate that sBCMA may independently predict primary refractoriness to anti-BCMA therapies. In addition to sBCMA, tumor burden and surface BCMA antigen density collectively influence anti-BCMA TCE cytotoxic efficacy. Correlative analyses of 163 patients treated with anti-BCMA TCE teclistamab validated and further underscored the association between elevated baseline sBCMA (>400 ng/mL) and refractoriness. Importantly, increasing TCE dose, the use of TCE against alternative targets (e.g.,GPRC5D), or gamma secretase inhibitors were able to overcome high sBCMA. These findings highlight the importance of accounting for baseline sBCMA levels, disease burden, and TCE dose intensity when administering anti-BCMA TCEs, offering critical insights for optimizing therapeutic strategies to overcome specific high-risk features and primary anti-BCMA TCE refractoriness.

Multiple cereblon genetic changes are associated with acquired resistance to lenalidomide or pomalidomide in multiple myeloma.

Emergence of drug resistance to all available therapies is the major challenge to improving survival in myeloma. Cereblon (CRBN) is the essential binding protein of the widely used immunomodulatory drugs (IMiDs) and novel CRBN E3 ligase modulator drugs (CELMoDs) in myeloma, as well as certain proteolysis targeting chimeras (PROTACs), in development for a range of diseases. Using whole-genome sequencing (WGS) data from 455 patients and RNA sequencing (RNASeq) data from 655 patients, including newly diagnosed (WGS, n = 198; RNASeq, n = 437), lenalidomide (LEN)-refractory (WGS, n = 203; RNASeq, n = 176), and pomalidomide (POM)-refractory cohorts (WGS, n = 54; RNASeq, n = 42), we found incremental increases in the frequency of 3 CRBN aberrations, namely point mutations, copy losses/structural variations, and a specific variant transcript (exon 10 spliced), with progressive IMiD exposure, until almost one-third of patients had CBRN alterations by the time they were POM refractory. We found all 3 CRBN aberrations were associated with inferior outcomes to POM in those already refractory to LEN, including those with gene copy losses and structural variations, a finding not previously described. This represents the first comprehensive analysis and largest data set of CBRN alterations in myeloma patients as they progress through therapy. It will help inform patient selection for sequential therapies with CRBN-targeting drugs.

Amyloidosis and COVID-19: experience from an amyloid program in Canada.

Severe acute respiratory syndrome coronavirus (SARS-CoV2) and associated COVID-19 infection continue to impact patients globally. Patients with underlying health conditions are at heightened risk of adverse outcomes from COVID-19; however, research involving patients with rare health conditions remains scarce. The amyloidoses are a rare grouping of protein deposition diseases. Light-chain and transthyretin amyloidosis are the most common disease forms, often present with systemic involvement of vital organs including the heart, nerves, kidneys, and GI tracts of affected individuals. The Amyloidosis Program of Calgary examined 152 ATTR patients and 103 AL patients analyzing rates of vaccination, COVID-19 testing, infection outcomes, influence referrals, and excess deaths. Results showed 15 total PCR-confirmed COVID-19 infections in the tested population of amyloid patients, with a higher frequency of infections among patient with AL compared to the ATTR cohort (26.2% vs 5.1%). Four patients (26.6%) required hospital admission for COVID-19 infection, 2 ATTR, and 2 AL patients. Of the confirmed cases, 1 (0.07%) unvaccinated ATTR patient died of a COVID-19 infection. An excess of deaths was found in both the ATTR and AL cohorts when comparing pre-pandemic years 2018 and 2019 to the pandemic years of 2020 and 2021. The finding suggests that amyloidosis patients are likely at a high risk for severe COVID-19 infection and mortality, especially those of advanced age, those on an active treatment with chemotherapy, and those with concomitant B-cell or plasma cell disorder. The impact of virtual healthcare visits and pandemic measures on the excess of deaths observed requires further research.

Impact of COVID-19 on the Diagnosis and Management of Multiple Myeloma: Experience from a Canadian Center.

BACKGROUND: The impact of coronavirus disease-19 on the management of multiple myeloma (MM) has been recognized. However, the real effect on clinical outcomes remains poorly understood. OBJECTIVE: We describe a local experience of the management of MM patients and report their outcomes during the current pandemic. METHODS: All consecutive symptomatic MM patients seen at our center since 03/20 were evaluated. RESULTS: A cohort of 156 patients diagnosed from 01/19 to 12/20 was analyzed to interrogate differences in presentation patterns. A total of 553 MM patients were seen and/or treated at Tom Baker Cancer Center in the year of 2020. From those, 47.1% (n = 261) were tested for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Sixteen patients tested positive and data are presented. In addition, a decrease of 21.7% in the rate of new smoldering MM/MM diagnosis was observed in 2020 as compared to 2019. Further, an increase in deaths was also observed in 2020. CONCLUSIONS: Our study confirms an increase lethality for MM patients infected with SARS-CoV-2. A balance between safety and need for cancer control should be emphasized.

N-Terminal pro-brain natriuretic peptide (NTproBNP) in patients with symptomatic multiple myeloma: report from a single institution.

Elevated levels of serum cardiovascular markers including natriuretic peptides (NPs) such as amino terminal pro-brain natriuretic peptide (NTproBNP) have been associated with disease severity and survival in cancer patients and more recently in multiple myeloma (MM). In the present study, we retrospectively reviewed 87 consecutive symptomatic TEMM (transplant-eligible) and 126 TIMM (transplant-ineligible) patients treated at our institution that did undergo NTproBNP testing from 2017 to 2020. Median age at diagnosis was 59.3 years and 75.4 years for the TEMM and TIMM groups, respectively (p = 0.0001). NTproBNP ≥ 300 ng/L was used to assess survival outcomes in the group of symptomatic MM. Patients with AL amyloidosis and symptomatic MM were excluded from the study. Median OS for patients with NTproBNP ≥ 300 ng/L was shorter (45.9 months) as compared to those with NTproBNP of < 300 ng/L (non-reached) (p = 0.0001). In addition, OS was shorter for those with CCI > 2, ISS2-3, and high-risk cytogenetics by FISH and ≥ 70 years of age. Multivariate analysis showed that HR cytogenetics and ISS2-3 were independent predictors for OS in the entire cohort of MM patients. When restricted to TIMM, age ≥ 80 years and NTproBNP ≥ 800 ng/L were predictors for OS in univariate and multivariate analyses. In conclusion, NTproBNP appears to be an independent predictor factor for OS in symptomatic TIMM patients. The use of NTproBNP as a frailty marker remains to be elucidated. However, NTproBNP could potentially be used to guide treatment decisions aimed to minimize cardiovascular and renal toxicity for myeloma therapies that potentially do have cardio-renal implications.

The impact of COVID-19 in the management of AL amyloidosis and Immunoglobulin Deposition Disease: A single-center experience.

INTRODUCTION: Patients with AL amyloidosis and immunoglobulin deposition diseases (IDD) are vulnerable during the COVID-19 pandemic due to the immune compromise from the plasma cell disorder and therapy-related immune defects. We describe a local experience in providing care for patients with AL amyloidosis and IDD. METHOD: Patient treatment and disease status since the beginning of the pandemic on March 11, 2020, as declared by WHO, were collected and analyzed. RESULTS: Ninety-six patients with AL amyloidosis and IDD were included. Four patients with IDD and 22 patients with systemic AL amyloidosis were receiving treatment during the pandemic. Since the pandemic, patients' treatments were discontinued if they achieved VGPR or better postinduction. Seven patients discontinued all treatment after achieving VGPR, and others required treatment modifications. 28 patients have been tested for COVID-19, and all tests have been negative. Three patients died since the pandemic, two from organ complications of systemic AL amyloidosis and one from an unrelated cause. CONCLUSION: The management of AL amyloidosis and IDD must be individualized on the clinical characteristics, centers' access to care under the pandemic restrictions, and the epidemiological aspects of the outbreak.