Delayed identification of monoclonal protein is associated with early death in isolated cardiac AL amyloidosis.

BACKGROUND: Early identification of immunoglobulin light-chain amyloidosis (AL) is crucial due to its rapid progression. Monoclonal light-chain (M-LC) testing is the first step in the diagnostic workup for patients with suspected cardiac amyloidosis (CA). We aimed to determine whether the time interval between the first CA suspicion and M-LC testing can be related to AL amyloidosis survival outcomes. METHODS: All patients (n = 94) with isolated cardiac AL amyloidosis diagnosed at our center between 2016 and 2020 were included. Those with pre-existing known monoclonal protein (monoclonal gammopathy of undetermined significance or smoldering multiple myeloma) were excluded. Time intervals to diagnostic tests and diagnosis were calculated and assessed for their survival prediction ability. RESULTS: The time interval between first CA suspicion (on echocardiography) and M-LC testing correlated with early mortality, and the best cutoff predicting survival, was 6 weeks. The 26 patients (∼28% of entire cohort) who underwent M-LC-studies >6 weeks after first suspicion more frequently presented Mayo stage IIIb (65% vs. 35%, p = .008), showing poorer overall survival than those (n = 68, 72%) referred for early M-LC studies (median 3 vs. 14 months, p = .039). CONCLUSIONS: Monoclonal protein testing should be the first-step in the diagnostic workup for patients with echocardiographic/other instrumental red flags raising CA suspicion.

A real-life study of daratumumab combinations in newly diagnosed patients with light chain (AL) amyloidosis.

Daratumumab-based regimens are the new standard of care for newly diagnosed patients with AL amyloidosis based on the results of the ANDROMEDA study. However, real-world data on daratumumab efficacy in upfront therapy in unselected patients are scanty. In the framework of a prospective observational study, we investigated the efficacy and safety of daratumumab in 88 newly diagnosed patients, including subjects with IIIb cardiac stage (26%) or myeloma defining events (29%). Daratumumab was administered with bortezomib in 50 (56%) patients, lenalidomide in 31 (35%), and monotherapy in 7 (8%). The rate of serious adverse events was low (16%). The overall hematologic response rate was 75% with 52 (59%) patients attaining at least a very good partial response (VGPR) at six months. Amongst patients evaluable for organ response, the rate of cardiac and renal responses at 6 months was 31% and 21%, respectively. Comparing stage IIIb patients with the remaining ones, the rate of profound hematologic response was not significantly different (≥VGPR 57% vs. 59%, p 0.955) likewise the rate of cardiac (33% vs. 30%, p 0.340) and renal (40% vs. 16%, p 0.908) responses. Daratumumab-based regimens demonstrated to be safe and effective in treatment-naïve AL amyloidosis even in advanced stage disease.

Renal alterations in cats (Felis catus) housed in shelters and affected by systemic AA-amyloidosis: Clinicopathological data, histopathology, and ultrastructural features.

AA-amyloidosis is frequent in shelter cats, and chronic kidney disease is the foremost cause of death. The aims were to describe kidney laboratory and microscopic findings in shelter cats with AA-amyloidosis. Cats were included if kidney specimens were collected post-mortem and laboratory data were available within 6 months before death. Renal lesions were evaluated with optical and electron microscopy. Mass spectrometry was used to characterize amyloid. Nine domestic short-hair cats were included; 4 females and 5 males with a median age of 8 years (range = 2-13). All cats had blood analyses and urinalyses available. Serum creatinine concentrations were increased in 6 cats and symmetric dimethylarginine was increased in all of the cats. All of the cats had proteinuria. Eight of 9 cats had amyloid in the medulla, and 9 had amyloid in the cortex (glomeruli). All cats had amyloid in the interstitium. Six cats had concurrent interstitial nephritis and 1 had membranoproliferative glomerulonephritis. All cats had extrarenal amyloid deposits. Amyloid was AA in each case. In conclusion, renal deposition of amyloid occurs in both cortex and medulla in shelter cats and is associated with azotemia and proteinuria. Renal involvement of systemic AA-amyloidosis should be considered in shelter cats with chronic kidney disease. The cat represents a natural model of renal AA-amyloidosis.

Cardiac complete response in AL amyloidosis has similar survival to matched general population.

The survival of patients achieving a cardiac complete response in AL amyloidosis, defined as NT-proBNP ≤350 pg/mL or BNP ≤80 pg/mL, was similar to a matched general population with an estimated 5-year survival rate of 93% vs 95%, respectively.

International Myeloma Working Group immunotherapy committee consensus guidelines and recommendations for optimal use of T-cell-engaging bispecific antibodies in multiple myeloma.

Multiple myeloma remains an incurable disease, despite the development of numerous drug classes and combinations that have contributed to improved overall survival. Immunotherapies directed against cancer cell-surface antigens, such as chimeric antigen receptor (CAR) T-cell therapy and T-cell-redirecting bispecific antibodies, have recently received regulatory approvals and shown unprecedented efficacy. However, these immunotherapies have unique mechanisms of action and toxicities that are different to previous treatments for myeloma, so experiences from clinical trials and early access programmes are essential for providing specific recommendations for management of patients, especially as these agents become available across many parts of the world. Here, we provide expert consensus clinical practice guidelines for the use of bispecific antibodies for the treatment of myeloma. The International Myeloma Working Group is also involved in the collection of prospective real-time data of patients treated with such immunotherapies, with the aim of learning continuously and adapting clinical practices to optimise the management of patients receiving immunotherapies.

Healthcare Resource Utilization and Cost-of-Illness in Systemic Light Chain (AL) Amyloidosis in Europe: Results From the Real-World, Retrospective EMN23 Study.

OBJECTIVES: To report healthcare resource utilization (HCRU) and safety outcomes in systemic light chain (AL) amyloidosis from the EMN23 study. MATERIALS AND METHODS: The retrospective, observational, multinational EMN23 study included 4,480 patients initiating first-line treatment for AL amyloidosis in 2004-2018 and assessed, among other objectives, HCRU and safety outcomes. HCRU included hospitalizations, examinations, and dialysis; safety included serious adverse events (SAEs) and adverse events of special interest (AESIs). Data were descriptively analyzed by select prognostic factors (e.g., cardiac staging by Mayo2004/European) for 2004-2010 and 2011-2018. A cost-of-illness analysis was conducted for the UK and Spain. RESULTS: HCRU/safety and dialysis data were extracted for 674 and 774 patients, respectively. Of patients with assessed cardiac stage (2004-2010: 159; 2011-2018: 387), 67.9% and 61.0% had ≥ 1 hospitalization, 56.0% and 51.4% had ≥ 1 SAE, and 31.4% and 28.9% had ≥ 1 AESI across all cardiac stages in 2004-2010 and 2011-2018, respectively. The per-patient-per-year length of hospitalization increased with disease severity (cardiac stage). Of patients with dialysis data (2004-2010: 176; 2011-2018: 453), 23.9% and 14.8% had ≥ 1 dialysis session across all cardiac stages in 2004-2010 and 2011-2018, respectively. The annual cost-of-illness was estimated at €40,961,066 and €31,904,386 for the UK and Spain, respectively; dialysis accounted for ∼28% (UK) and ∼35% (Spain) of the total AL amyloidosis costs. CONCLUSIONS: EMN23 showed that the burden of AL amyloidosis is substantial, highlighting the need for early disease diagnosis and effective treatments targeting the underlying pathology.

Mining the amyloid-plaque proteome to uncover disease mechanisms in renal amyloidoses.

Beyond typing amyloid deposits and discovering new forms of amyloidosis, laser microdissection and mass spectrometry enable the analysis of the amyloid-plaque proteome constituents-amyloid fibrillar proteins, matrix and cellular components, and absorbed blood-borne proteins. Charalampous et al. analyzed the amyloid-plaque proteomes of the 7 most common renal amyloidoses to gain preliminary mechanistic insights on cellular and molecular perturbations elicited during gradual amyloid deposition and potential tissue repair or damage mechanisms. Clinical correlations identified a prognostic pattern.

Patient-reported outcome measures for transthyretin cardiac amyloidosis: the ITALY study.

BACKGROUND: Transthyretin cardiac amyloidosis (ATTR-CA) has a deep impact on the quality of life (QoL), yet no specific patient-reported outcome measures (PROMs) for ATTR-CA exist. METHODS: The ITALY study involved 5 Italian referral centres (Pisa, Pavia, Ferrara, Florence, Messina) enrolling consecutive outpatients with ATTR-CA. RESULTS: Two 30-item questionnaires were created for wild-type (wt) and variant (v) ATTR-CA. Scores ranged from 100 (best condition) to 0 (worst condition). Out of 140 patients enrolled (77% with ATTRwt-CA), 115 repeated the re-evaluation at 6 months. At baseline, only 30% of patients needed help to fill out the questionnaires. Among baseline variables, all KCCQ and SF-36 domains were univariate predictors of ITALY scores in ATTRwt-CA patients, with the KCCQ Symptom Summary score (beta coefficient 0.759), Social Limitations (0.781), and Overall summary score (0.786) being the strongest predictors. The SF-36 Emotional well-being score (0.608), the KCCQ Overall summary score (0.656), and the SF-36 Energy/fatigue score (0.669) were the strongest univariate predictors of ITALY scores in ATTRv-CA. Similar results were found at 6 months. CONCLUSIONS: The ITALY questionnaires are the first specific PROMs for ATTRwt- and ATTRv-CA. Questionnaire completion is feasible. ITALY scores display close relationships with non-ATTR-specific measures of QoL.

Nanobodies counteract the toxicity of an amyloidogenic light chain by stabilizing a partially open dimeric conformation.

Light chain amyloidosis (AL) is a systemic disease where fibrillar deposition of misfolded immunoglobulin light chains (LCs) severely affects organ function and results in poor prognosis for patients, especially when heart involvement is severe. Particularly relevant in this context is the cardiotoxicity exerted by still uncharacterized soluble LC species. Here, with the final goal of identifying alternative therapeutic strategies to tackle AL amyloidosis, we produced five llama-derived nanobodies (Nbs) specific against H3, a well-characterized amyloidogenic and cardiotoxic LC from an AL patient with severe cardiac involvement. We found that Nbs are specific and potent agents capable of abolishing H3 soluble toxicity in C. elegans in vivo model. Structural characterization of H3-Nb complexes revealed that the protective effect of Nbs is related to their ability to bind to the H3 VL domain and stabilise an unexpected partially open LC dimer in which the two VL domains no longer interact with each other. Thus, while identifying potent inhibitors of LC soluble toxicity, we also describe the first non-native structure of an amyloidogenic LC that may represent a crucial step in toxicity and aggregation mechanisms.

The Cryo-EM STRUCTURE of Renal Amyloid Fibril Suggests Structurally Homogeneous Multiorgan Aggregation in AL Amyloidosis.

Immunoglobulin light chain amyloidosis (AL) is caused by the aberrant production of amyloidogenic light chains (LC) that accumulate as amyloid deposits in vital organs. Distinct LC sequences in each patient yield distinct amyloid structures. However different tissue microenvironments may also cause identical protein precursors to adopt distinct amyloid structures. To address the impact of the tissue environment on the structural polymorphism of amyloids, we extracted fibrils from the kidney of an AL patient (AL55) whose cardiac amyloid structure was previously determined by our group. Here we show that the 4.0 Å resolution cryo-EM structure of the renal fibril is virtually identical to that reported for the cardiac fibril. These results provide the first structural evidence that LC amyloids independently deposited in different organs of the same AL patient share a common fold.

Management of multiple myeloma-related renal impairment: recommendations from the International Myeloma Working Group.

Here, the International Myeloma Working Group (IMWG) updates its clinical practice recommendations for the management of multiple myeloma-related renal impairment on the basis of data published until Dec 31, 2022. All patients with multiple myeloma and renal impairment should have serum creatinine, estimated glomerular filtration rate, and free light chains (FLCs) measurements together with 24-h urine total protein, electrophoresis, and immunofixation. If non-selective proteinuria (mainly albuminuria) or involved serum FLCs value less than 500 mg/L is detected, then a renal biopsy is needed. The IMWG criteria for the definition of renal response should be used. Supportive care and high-dose dexamethasone are required for all patients with myeloma-induced renal impairment. Mechanical approaches do not increase overall survival. Bortezomib-based regimens are the cornerstone of the management of patients with multiple myeloma and renal impairment at diagnosis. New quadruplet and triplet combinations, including proteasome inhibitors, immunomodulatory drugs, and anti-CD38 monoclonal antibodies, improve renal and survival outcomes in both newly diagnosed patients and those with relapsed or refractory disease. Conjugated antibodies, chimeric antigen receptor T-cells, and T-cell engagers are well tolerated and effective in patients with moderate renal impairment.

Birtamimab plus standard of care in light-chain amyloidosis: the phase 3 randomized placebo-controlled VITAL trial.

Amyloid light-chain (AL) amyloidosis is a rare, typically fatal disease characterized by the accumulation of misfolded immunoglobulin light chains (LCs). Birtamimab is an investigational humanized monoclonal antibody designed to neutralize toxic LC aggregates and deplete insoluble organ-deposited amyloid via macrophage-induced phagocytosis. VITAL was a phase 3 randomized, double-blind, placebo-controlled clinical trial assessing the efficacy and safety of birtamimab + standard of care (SOC) in 260 newly diagnosed, treatment-naive patients with AL amyloidosis. Patients received 24 mg/kg IV birtamimab + SOC or placebo + SOC every 28 days. The primary composite end point was the time to all-cause mortality (ACM) or centrally adjudicated cardiac hospitalization ≥91 days after the first study drug infusion. The trial was terminated early after an interim futility analysis; there was no significant difference in the primary composite end point (hazard ratio [HR], 0.826; 95% confidence interval [CI], 0.574-1.189; log-rank P = .303). A post hoc analysis of patients with Mayo stage IV AL amyloidosis, those at the highest risk of early mortality, showed significant improvement in the time to ACM with birtamimab at month 9 (HR, 0.413; 95% CI, 0.191-0.895; log-rank P = .021). At month 9, 74% of patients with Mayo stage IV AL amyloidosis treated with birtamimab and 49% of those given placebo survived. Overall, the rates of treatment-emergent adverse events (TEAEs) and serious TEAEs were generally similar between treatment arms. A confirmatory phase 3 randomized, double-blind, placebo-controlled clinical trial of birtamimab in patients with Mayo stage IV AL amyloidosis (AFFIRM-AL; NCT04973137) is currently enrolling. The VITAL trial was registered at www.clinicaltrials.gov as #NCT02312206.

Amyloidogenic light chains impair plasma cell survival.

Systemic light chain amyloidosis (AL) is a clonal plasma cell disorder characterized by the deposition of misfolded immunoglobulin light chains (LC) as insoluble fibrils in organs. The lack of suitable models has hindered the investigation of the disease mechanisms. Our aim was to establish AL LC-producing plasma cell lines and use them to investigate the biology of the amyloidogenic clone. We used lentiviral vectors to generate cell lines expressing LC from patients suffering from AL amyloidosis. The AL LC-producing cell lines showed a significant decrease in proliferation, cell cycle arrest, and an increase in apoptosis and autophagy as compared with the multiple myeloma LC-producing cells. According to the results of RNA sequencing the AL LC-producing lines showed higher mitochondrial oxidative stress, and decreased activity of the Myc and cholesterol pathways. The neoplastic behavior of plasma cells is altered by the constitutive expression of amyloidogenic LC causing intracellular toxicity. This observation may explain the disparity in the malignant behavior of the amyloid clone compared to the myeloma clone. These findings should enable future in vitro studies and help delineate the unique cellular pathways of AL, thus expediting the development of specific treatments for patients with this disorder.

A Strategy for the Selection of RT-qPCR Reference Genes Based on Publicly Available Transcriptomic Datasets.

In the next-generation sequencing era, RT-qPCR is still widely employed to quantify levels of nucleic acids of interest due to its popularity, versatility, and limited costs. The measurement of transcriptional levels through RT-qPCR critically depends on reference genes used for normalization. Here, we devised a strategy to select appropriate reference genes for a specific clinical/experimental setting based on publicly available transcriptomic datasets and a pipeline for RT-qPCR assay design and validation. As a proof-of-principle, we applied this strategy to identify and validate reference genes for transcriptional studies of bone-marrow plasma cells from patients with AL amyloidosis. We performed a systematic review of published literature to compile a list of 163 candidate reference genes for RT-qPCR experiments employing human samples. Next, we interrogated the Gene Expression Omnibus to assess expression levels of these genes in published transcriptomic studies on bone-marrow plasma cells from patients with different plasma cell dyscrasias and identified the most stably expressed genes as candidate normalizing genes. Experimental validation on bone-marrow plasma cells showed the superiority of candidate reference genes identified through this strategy over commonly employed "housekeeping" genes. The strategy presented here may apply to other clinical and experimental settings for which publicly available transcriptomic datasets are available.

Report of Consensus Panel 6 from the 11 th International Workshop on Waldenström's Macroglobulinemia on Management of Waldenström's Macroglobulinemia Related Amyloidosis.

Consensus Panel 6 (CP6) of the 11th International Workshop on Waldenström's Macroglobulinemia (IWWM-11) was tasked with reviewing the state of the art for diagnosis, prognosis, and therapy of AL amyloidosis associated with Waldenström macroglobulinemia (WM). Since significant advances have been made in the management of AL amyloidosis an update for this rare disease associated with WM was necessary. The key recommendations from IWWM-11 CP6 included: (1) The need to improve the diagnostic process by recognizing red flags and using biomarkers and imaging; (2) The essential tests for appropriate workup; (3) The diagnostic flowchart, including mandatory amyloid typing, that improves the differential diagnosis with transthyretin amyloidosis; (4) Criteria for therapy response assessment; (5) State of the art of the treatment including therapy of wild type transthyretin amyloidosis associated with WM.

Definition and Clinical Significance of the Monoclonal Gammopathy of Undetermined Significance-Like Phenotype in Patients With Monoclonal Gammopathies.

PURPOSE: The existence of patients with multiple myeloma (MM) and light-chain (AL) amyloidosis who present with a monoclonal gammopathy of undetermined significance (MGUS)-like phenotype has been hypothesized, but methods to identify this subgroup are not standardized and its clinical significance is not properly validated. PATIENTS AND METHODS: An algorithm to identify patients having MGUS-like phenotype was developed on the basis of the percentages of total bone marrow (BM) plasma cells (PC) and of clonal PC within the BM PC compartment, determined at diagnosis using flow cytometry in 548 patients with MGUS and 2,011 patients with active MM. The clinical significance of the algorithm was tested and validated in 488 patients with smoldering MM, 3,870 patients with active MM and 211 patients with AL amyloidosis. RESULTS: Patients with smoldering MM with MGUS-like phenotype showed significantly lower rates of disease progression (4.5% and 0% at 2 years in two independent series). There were no statistically significant differences in time to progression between treatment versus observation in these patients. In active newly diagnosed MM, MGUS-like phenotype retained independent prognostic value in multivariate analyses of progression-free survival (PFS; hazard ratio [HR], 0.49; P = .001) and overall survival (OS; HR, 0.56; P = .039), together with International Staging System, lactate dehydrogenase, cytogenetic risk, transplant eligibility, and complete remission status. Transplant-eligible patients with active MM with MGUS-like phenotype showed PFS and OS rates at 5 years of 79% and 96%, respectively. In this subgroup, there were no differences in PFS and OS according to complete remission and measurable residual disease status. Application of the algorithm in two independent series of patients with AL predicted for different survival. CONCLUSION: We developed an open-access algorithm for the identification of MGUS-like patients with distinct clinical outcomes. This phenotypic classification could become part of the diagnostic workup of MM and AL amyloidosis.

Echocardiographic findings in subjects with an amyloidogenic apolipoprotein A1 pathogenic variant.

BACKGROUND: Very small case series of patients with apolipoprotein A1 (ApoA1) amyloidosis are available. METHODS: We described the clinical and echocardiographic characteristics of individuals with the pathogenic APOA1 variant Leu75Pro (p. Leu99Pro), referred for cardiac screening. RESULTS: We enrolled 189 subjects, 54% men, median age 55 years (interquartile range 42-67), 39% with concomitant renal disease and 31% with liver disease. Median left ventricular ejection fraction was 60% (55-66). Overall, these subjects did not show overt diastolic dysfunction nor left ventricular (LV) hypertrophy. Age correlated with interventricular septal (IVS) thickness (r = 0.484), LV mass index (r = 0.459), E/e' (r = 0.501), and right ventricular free wall thickness (r = 0.594) (all p < 0.001). Some individuals displayed red flags for cardiac amyloidosis (CA), and 14% met non-invasive criteria for CA. Twenty-nine subjects died over 5.8 years (4.1-8.0), with 10 deaths for cardiovascular causes. Individuals meeting echocardiographic criteria for CA had a much higher risk of all-cause death (p = 0.009), cardiovascular death (p = 0.001), cardiovascular death or heart failure (HF) hospitalisation (p < 0.001). Subjects with both renal and liver involvement had a more prominent cardiac involvement, and shortest survival. CONCLUSIONS: Subjects with the APOA1 Leu75Pro variant displayed minor echocardiographic signs of cardiac involvement, but 14% met echocardiographic criteria for CA. Subjects with suspected CA had a worse outcome.