Systemic immunoglobulin light chain amyloidosis

Prospective urinary albumin/creatinine ratio for diagnosis, staging, and organ response assessment in renal AL amyloidosis: results from a large cohort of patients

OBJECTIVES

Quantification of 24 h-proteinuria is the gold standard for diagnosing, staging, and monitoring of patients with renal AL amyloidosis. However, 24 h-urine collection is cumbersome and may result in preanalytical error. In this prospective study, we investigated the role of urinary albumin/creatinine ratio (UACR) (cut-off: 300 mg/g) identifying renal involvement, evaluated a UACR-based staging system (UACR cut-off: 3,600 mg/g) and assessed whether UACR response (UACR decrease >30% without worsening in eGFR >25%) predicts renal outcome in 531 patients with newly-diagnosed AL amyloidosis.

METHODS

From October 2013 paired 24 h-proteinuria and UACR (on first morning void) were measured in all newly-diagnosed patients with AL amyloidosis. Correlation between 24 h-proteinuria and UACR at baseline was assessed by Pearson's r test. Impact of UACR response on renal outcome was assessed in randomly created testing (n=354) and validation (n=177) cohorts.

RESULTS

A strong linear correlation was found between 24 h-proteinuria and UACR at baseline (r=0.90; p<0.001). After a median follow-up of 31 months, 57 (11%) patients required dialysis. A UACR-based renal staging system identified three stages with significantly higher dialysis rate at 36 months comparing stage I with stage II and stage II with stage III. Achieving a renal response, according to a UACR-based criterion, resulted in lower dialysis rate in both testing and validation cohorts.

CONCLUSIONS

UACR is a reliable marker for diagnosis, prognosis, and organ response assessment in renal AL amyloidosis and can reliably replace 24 h-proteinuria in clinical trials and individual patients' management.

Challenges of repurposing tetracyclines for the treatment of Alzheimer's and Parkinson's disease

The novel antibiotic-exploiting strategy in the treatment of Alzheimer's (AD) and Parkinson's (PD) disease has emerged as a potential breakthrough in the field. The research in animal AD/PD models provided evidence on the antiamyloidogenic, anti-inflammatory, antioxidant and antiapoptotic activity of tetracyclines, associated with cognitive improvement. The neuroprotective effects of minocycline and doxycycline in animals initiated investigation of their clinical efficacy in AD and PD patients which led to inconclusive results and additionally to insufficient safety data on a long-standing doxycycline and minocycline therapy in these patient populations. The safety issues should be considered in two levels; in AD/PD patients (particularly antibiotic-induced alteration of gut microbiota and its consequences), and as a world-wide threat of development of bacterial resistance to these antibiotics posed by a fact that AD and PD are widespread incurable diseases which require daily administered long-lasting antibiotic therapy. Recently proposed subantimicrobial doxycycline doses should be thoroughly explored for their effectiveness and long-term safety especially in AD/PD populations. Keeping in mind the antibacterial activity-related far-reaching undesirable effects both for the patients and globally, further work on repurposing these drugs for a long-standing therapy of AD/PD should consider the chemically modified tetracycline compounds tailored to lack antimicrobial but retain (or introduce) other activities effective against the AD/PD pathology. This strategy might reduce the risk of long-term therapy-related adverse effects (particularly gut-related ones) and development of bacterial resistance toward the tetracycline antibiotic agents but the therapeutic potential and desirable safety profile of such compounds in AD/PD patients need to be confirmed.

Predictive factors of outcomes in patients with AL amyloidosis treated with daratumumab

Daratumumab as a single agent (sDARA) or in combination with chemotherapies (cDARA) leads to impressive hematologic and organ responses in AL amyloidosis. However, predictive factors associated with outcomes, and optimal duration of therapy remain unclear. We analyzed 107 patients with AL amyloidosis treated with daratumumab between 2017 and 2020. The median overall survival (OS) was not reached while the median major organ deterioration progression free survival (MOD-PFS) was 36 months in the sDARA cohort and not reached in the cDARA cohort, respectively. Hematologic response > VGPR was achieved in 81% of patients receiving sDARA and 86% of patients treated with cDARA. Several predictive factors were identified on a univariate analysis, including NTproBNP >8500 pg/mL but only achievement of at least VGPR and presence of 1q21 gain were independently associated with MOD-PFS and OS on a multivariate analysis. Finally, patients receiving > 12 cycles had significantly longer MOD-PFS (30 vs.13 months; (p = .0018) and OS (NR vs. 15 months; p < .0001). NTproBNP > 8500 pg/mL, presence of 1q21 gain and shorter duration of therapy (≤ 12 cycles) are strong negative predictive factors for outcomes with daratumumab therapy in AL amyloidosis.

Classification of Amyloidosis by Model-Assisted Mass Spectrometry-Based Proteomics

Amyloidosis is a rare disease caused by the misfolding and extracellular aggregation of proteins as insoluble fibrillary deposits localized either in specific organs or systemically throughout the body. The organ targeted and the disease progression and outcome is highly dependent on the specific fibril-forming protein, and its accurate identification is essential to the choice of treatment. Mass spectrometry-based proteomics has become the method of choice for the identification of the amyloidogenic protein. Regrettably, this identification relies on manual and subjective interpretation of mass spectrometry data by an expert, which is undesirable and may bias diagnosis. To circumvent this, we developed a statistical model-assisted method for the unbiased identification of amyloid-containing biopsies and amyloidosis subtyping. Based on data from mass spectrometric analysis of amyloid-containing biopsies and corresponding controls. A Boruta method applied on a random forest classifier was applied to proteomics data obtained from the mass spectrometric analysis of 75 laser dissected Congo Red positive amyloid-containing biopsies and 78 Congo Red negative biopsies to identify novel “amyloid signature” proteins that included clusterin, fibulin-1, vitronectin complement component C9 and also three collagen proteins, as well as the well-known amyloid signature proteins apolipoprotein E, apolipoprotein A4, and serum amyloid P. A SVM learning algorithm were trained on the mass spectrometry data from the analysis of the 75 amyloid-containing biopsies and 78 amyloid-negative control biopsies. The trained algorithm performed superior in the discrimination of amyloid-containing biopsies from controls, with an accuracy of 1.0 when applied to a blinded mass spectrometry validation data set of 103 prospectively collected amyloid-containing biopsies. Moreover, our method successfully classified amyloidosis patients according to the subtype in 102 out of 103 blinded cases. Collectively, our model-assisted approach identified novel amyloid-associated proteins and demonstrated the use of mass spectrometry-based data in clinical diagnostics of disease by the unbiased and reliable model-assisted classification of amyloid deposits and of the specific amyloid subtype.

Work Outcomes Among Patients with Light Chain (AL) Amyloidosis: Findings from Three Patient Cohorts

Background

Light chain (AL) amyloidosis is a rare and progressive disease that affects myriad organs and systems. Patients with cardiac involvement have the highest risk of death. This report compiles findings across three cohorts of patients with AL amyloidosis to understand patterns of employment and work impacts.

Methods

Data came from three cohorts recruited through patient advocacy organizations in the US. Patients in Cohort 1 completed the SF-36v2^® Health Survey (SF-36v2), the Work Productivity and Activity Impairments – Specific Health Problem (WPAI) questionnaire, and the 12-item Kansas City Cardiomyopathy Questionnaire (KCCQ-12). The relationship between work impacts (WPAI scores) and HRQoL (SF-36v2 scores) was investigated using multivariable logistic regression and summarized according to cardiac severity using New York Heart Association (NYHA) classes estimated from KCCQ-12 scores. Changes in employment, days of missed work, and long-term disability due to AL amyloidosis were summarized for patients diagnosed in the past 24 months and stratified by NYHA class (Cohort 2). Findings were contextualized using patient interviews (Cohort 3).

Results

Work-related impacts, especially reduced productivity, were common among patients with AL amyloidosis. WPAI scores were significantly related to HRQoL (p<0.05 for all models). Among patients with cardiac involvement, the greatest degree of work impacts was observed for those in NYHA class 3 or 4. Changes in employment, missed work, and long-term disability were common among newly diagnosed patients, especially among those in NYHA class 3 or 4. Patient interviews supported the survey findings; patients described absences, reduced productivity at work, and loss of employment due to the disease and its treatment.

Conclusion

Patients with AL amyloidosis, particularly those with more advanced disease, experience impacts across a range of employment-related outcomes. These findings highlight the need for more effective treatments and interventions which may improve functioning and patient outcomes, while reducing indirect costs associated with the disease.

Molecular Mechanisms of Cardiac Amyloidosis

Cardiac involvement has a profound effect on the prognosis of patients with systemic amyloidosis. Therapeutic methods for suppressing the production of causative proteins have been developed for ATTR amyloidosis and AL amyloidosis, which show cardiac involvement, and the prognosis has been improved. However, a method for removing deposited amyloid has not been established. Methods for reducing cytotoxicity caused by amyloid deposition and amyloid precursor protein to protect cardiovascular cells are also needed. In this review, we outline the molecular mechanisms and treatments of cardiac amyloidosis.

A Conservative Point Mutation in a Dynamic Antigen-binding Loop of Human Immunoglobulin λ6 Light Chain Promotes Pathologic Amyloid Formation

Immunoglobulin light chain (LC) amyloidosis (AL) is a life-threatening human disease wherein free mono-clonal LCs deposit in vital organs. To determine what makes some LCs amyloidogenic, we explored patient-based amyloidogenic and non-amyloidogenic recombinant LCs from the λ6 subtype prevalent in AL. Hydrogen-deuterium exchange mass spectrometry, structural stability, proteolysis, and amyloid growth studies revealed that the antigen-binding CDR1 loop is the least protected part in the variable domain of λ6 LC, particularly in the AL variant. N32T substitution in CRD1 is identified as a driver of amyloid formation. Substitution N32T increased the amyloidogenic propensity of CDR1 loop, decreased its protection in the native structure, and accelerated amyloid growth in the context of other AL substitutions. The destabilizing effects of N32T propagated across the molecule increasing its dynamics in regions ∼30 Å away from the substitution site. Such striking long-range effects of a conservative point substitution in a dynamic surface loop may be relevant to Ig function. Comparison of patient-derived and engineered proteins showed that N32T interactions with other substitution sites must contribute to amyloidosis. The results suggest that CDR1 is critical in amyloid formation by other λ6 LCs.

A Pilot Study of Rare Renal Amyloidosis Based on FFPE Proteomics

Renal amyloidosis typically manifests albuminuria, nephrotic-range proteinuria, and ultimately progresses to end-stage renal failure if diagnosed late. Different types of renal amyloidosis have completely different treatments and outcomes. Therefore, amyloidosis typing is essential for disease prognosis, genetic counseling and treatment. Thirty-six distinct proteins currently known to cause amyloidosis that have been described as amyloidogenic precursors, immunohistochemistry (IHC) or immunofluorescence (IF), can be challenging for amyloidosis typing especially in rare or hereditary amyloidosis in clinical practice. We made a pilot study that optimized the proteomics pre-processing procedures for trace renal amyloidosis formalin-fixed paraffin-embedded (FFPE) tissue samples, combined with statistical and bioinformatics analysis to screen out the amyloidosis-related proteins to accurately type or subtype renal amyloidosis in order to achieve individual treatment. A sensitive, specific and reliable FFPE-based proteomics analysis for trace sample manipulation was developed for amyloidosis typing. Our results not only underlined the great promise of traditional proteomics and bioinformatics analysis using FFPE tissues for amyloidosis typing, but also proved that retrospective diagnosis and analysis of previous cases laid a solid foundation for personalized treatment.

Three Primary Cancers in a Veteran With Agent Orange and Agent Blue Exposures

A Vietnam War veteran's exposures likely contributed to his cancer diagnoses, but these associations are confounded by his substance use, particularly cigarette smoking.

Role of mutations and post-translational modifications in systemic AL amyloidosis studied by cryo-EM

Systemic AL amyloidosis is a rare disease that is caused by the misfolding of immunoglobulin light chains (LCs). Potential drivers of amyloid formation in this disease are post-translational modifications (PTMs) and the mutational changes that are inserted into the LCs by somatic hypermutation. Here we present the cryo electron microscopy (cryo-EM) structure of an ex vivo λ1-AL amyloid fibril whose deposits disrupt the ordered cardiomyocyte structure in the heart. The fibril protein contains six mutational changes compared to the germ line and three PTMs (disulfide bond, N-glycosylation and pyroglutamylation). Our data imply that the disulfide bond, glycosylation and mutational changes contribute to determining the fibril protein fold and help to generate a fibril morphology that is able to withstand proteolytic degradation inside the body.

AL Amyloidosis: Current Chemotherapy and Immune Therapy Treatment Strategies: JACC: CardioOncology State-of-the-Art Review

Immunoglobulin light chain (AL) amyloidosis is an incurable plasma cell disorder characterized by deposition of fibrils of misfolded immunoglobulin free light chains (FLC) in target organs, leading to failure. Cardiac involvement is common in AL amyloidosis and represents the single most adverse prognostic feature. A high index of clinical suspicion with rapid tissue diagnosis and commencement of combinatorial, highly effective cytoreductive therapy is crucial to arrest the process of amyloid deposition and preserve organ function. The clinical use of molecularly targeted drugs, such as proteasome inhibitors and immunomodulatory agents, monoclonal antibodies such as daratumumab, and risk-adjusted autologous stem cell transplant in eligible patients, has radically changed the natural history of AL amyloidosis. Here, we review the state-of-the-art treatment landscape in AL amyloidosis with an eye toward future therapeutic venues to impact the outcome of this devastating illness.

T cell landscape and dynamics in immunoglobulin light chain amyloidosis before and after daratumumab-based therapy

Amyloid light-chain (AL) is characterized by the presence of small, poorly proliferating plasma cell clones with the production and deposition of light chains into tissues. T cell changes within the tumour microenvironment in AL are poorly understood. By sequencing at a single-cell level of CD3+ T cells purified from bone marrow (BM) and blood of newly diagnosed AL patients before and after a combination of daratumumab with cyclophosphamide, bortezomib, and dexamethasone (Dara-BCD), we analysed the transcriptomic features of T cells and found an expansion, activation and type I cytokine upregulation in BM and circulating T cells after the treatment. More prominent changes were shown in CD8+ T cells. In particular, we found the presence of CD8+ BM resident memory T cells (TRM ) with high expression of inhibitory molecules in AL patients at diagnosis. After Dara-BCD, these TRM cells were quickly activated with downregulation of suppressive molecules and upregulation of IFNG expression. These data collectively demonstrate that Dara-based therapy in patients with AL amyloidosis promotes anti-tumour T cell responses. The similar transcriptomic features of BM and circulating T cells before and after therapy further provide a less invasive approach for molecular monitoring of T cell response in AL amyloidosis.

Transient disorder along pathways to amyloid

High-resolution structures of amyloid fibrils formed from normally-folded proteins have revealed non-native conformations of the polypeptide chains. Attaining these conformations apparently requires transition from the native state via a highly disordered conformation, in contrast to earlier models that posited a role for assembly of partially folded proteins. Modifications or interactions that extend the lifetime or constrain the conformations of these disordered states could act to enhance or suppress amyloid formation. Understanding how the properties of both the folded and transiently disordered structural ensembles influence the process of amyloid formation is a substantial challenge, but research into the properties of intrinsically disordered proteins will deliver important insights.

Population Pharmacokinetics and Exposure-Response Modeling of Daratumumab Subcutaneous Administration in Patients With Light-Chain Amyloidosis

The purpose of this study is to characterize the population pharmacokinetics (popPK) of subcutaneous (SC) daratumumab in combination with bortezomib, cyclophosphamide, and dexamethasone and explore the relationship between daratumumab systemic exposure and selected efficacy and safety end points in patients with newly diagnosed systemic amyloid light-chain amyloidosis. The popPK analysis included pharmacokinetic and immunogenicity data from patients receiving daratumumab SC in combination with bortezomib, cyclophosphamide, and dexamethasone in the ANDROMEDA study (AMY3001; safety run-in, n = 28; randomized phase, n = 183). Nonlinear mixed-effects modeling was used to characterize the popPK and quantify the impact of potential covariates. The exposure-response (E-R) analysis included data from all patients in the randomized phase of ANDROMEDA (n = 388). Logistic regression and survival analysis were used to evaluate the relationships between daratumumab systemic exposure and efficacy end points. The E-R analysis on safety was conducted using quartile comparison and logistic regression analysis. The observed concentration-time data of daratumumab SC were well described by a 1-compartment popPK model with first-order absorption and parallel linear and nonlinear Michaelis-Menten elimination pathways. None of the investigated covariates were determined to be clinically meaningful. Daratumumab systemic exposure was generally similar across subgroups that achieved different levels of hematologic response, and there was no apparent relationship between daratumumab systemic exposure and the investigated safety end points. In conclusion, the popPK and E-R analyses supported the selected 1800-mg flat dose of daratumumab SC in combination with bortezomib, cyclophosphamide, and dexamethasone regimen for the treatment of light-chain amyloidosis. No dose adjustment was recommended for investigated covariates.

A Case Report of Cardiac Amyloidosis Highlighting the Importance of Strain Analysis

Cardiac involvement in light-chain (AL) amyloidosis has a high mortality. Once cardiac symptoms are present, it is important to make a diagnosis as there is an inverse relationship between mortality and time of diagnosis. Echocardiography is usually one of the first tests performed. But strain analysis, which can provide important clues, is not routinely performed. This is a case of AL amyloidosis presenting with heart failure in which echocardiographic strain analysis was vital for its diagnosis.

Successful Treatment of Factor X Deficiency in a Patient with Lymphoplasmacytic Lymphoma with Bendamustine Plus Rituximab Regimen: A Case Report and Literature Review

Background

Acquired factor X deficiency is an uncommon condition, and affected individuals have severe and spontaneous bleeding. The associated conditions include malignancy, infection, burn, and inflammatory bowel disease. Many previous studies reported association between lymphoproliferative disease and factor X disappearance. Amyloid deposition causing factor X absorption was the most common mechanism. Here, we report a case of stage IV lymphoplasmacytic lymphoma (LPL) with factor X deficiency who was successfully treated with bendamustine plus rituximab (BR) regimen.

Case Presentation

A 52-year-old Thai woman presented with heavy menorrhea, hoarseness, and widespread ecchymosis at her extremities. On physical examination, the patient had bilateral periorbital purpura and vocal cord hematoma. Coagulation testing showed prolonged prothrombin time (PT) and prolonged activated thromboplastin time (aPTT); however, after mixing with 1:1 normal pooled plasma, PT and aPTT were both corrected to normal levels. Factor assays demonstrated markedly decreased factor X levels, but no presence of factor X inhibitor. Bone marrow examination revealed numerous abnormal lymphoplasmacytoid lymphocytes with kappa light chain expression. Serum free light chain assay also showed kappa light chain restriction [kappa 716.16 mg/L, lambda 16.96 mg/L, ratio 42.23 (0.26–1.65)]. The patient was diagnosed as lymphoplasmacytic lymphoma with factor X deficiency. She received chemotherapy with 6 cycles of bendamustine plus rituximab (BR) regimen. The patient responded favorably to treatment, she remains in lymphoma remission at one year after diagnosis, and her factor X level was more than 20%.

Conclusion

We performed a literature review to identify previous case reports about lymphoma-associated factor X deficiency or inhibitor to determine a possible explanation in our patient. It is important to emphasize that when patients present with acquired factor deficiency, including factor X, lymphoproliferative disease is commonly one of the underlying conditions. Furthermore, the recovery of coagulation factor deficiency is possible if successful remission of lymphoma can be achieved.

Conduction abnormalities and role of cardiac pacing in cardiac amyloidosis: A systematic review

Cardiac amyloidosis (CA) is an increasingly recognized cause of heart failure, characterized by extracellular deposition of insoluble protein fibrils leading to progressive myocardial dysfunction. The most common types of cardiac amyloidosis are immunoglobin light-chain (AL) and transthyretin (ATTR). Conduction abnormalities are commonly encountered among patients with cardiac amyloidosis and are an important cause of morbidity and mortality. Abnormalities range from infra-Hisian intraventricular conduction delay and bundle branch block to complete atrioventricular block. Pacemaker placement in CA patients follows established guidelines, similar to those for patients without CA, with generally good efficacy. The role and appropriate timing of pacemakers for primary prevention of brady-arrhythmias in CA remains uncertain. While biventricular (BiV) pacing has been shown to improve clinical outcomes in patients with systolic heart failure without CA, there are few data examining the utility of BiV pacing in patients with CA. With the advent of effective treatments for AL and ATTR, appropriate application of pacing is important to support patients with CA and conduction disease through therapeutic trials. This systematic review summarizes the current literature examining the utility of pacing in CA.

[Heart damage in the combined types of systemic amyloidosis]

The cardiovascular system is a common target of systemic amyloidosis (SA); amyloid light chain (AL) cardiac amyloidosis (AL-CA), the wild-type transthyretin (ATTRwt-CA), and mutant-type transthyretin (ATTRmt-CA) are the most studied types of SA. The literature describes only single cases of two types of SA in the same patient.

OBJECTIVE

To identify and determine the clinical and morphological characteristics of combined types of SA in patients with biventricular chronic heart failure (CHF).

MATERIAL AND METHODS

Eighty autopsy protocols for biventricular CHF deaths were retrospectively analyzed. Immunohistochemistry and confocal laser scanning microscopy (CLCM) with antibodies to amyloid A (AA), serum amyloid-P (SAP), prealbumin, and immunoglobulin kappa (κ) and lambda (λ) light chains were performed.

RESULTS

The myocardium showed a combination of different types of SA in 6 (7.5%) cases, including Alλ-CA+ATTR-CA, ALκ-CA+ATTR-CA, and AA-CA+ATTR-CA in 4, 1, and 1 cases, respectively. Macroscopically, the heart mass averaged 470±20 g; the thickness of the left and right ventricular myocardium was 1.5±0.2 and 0.4±0.1 cm, respectively; the interventricular septum averaged 1.2±0.2 cm; and the cardiac index was 0.008. The myocardium was dense, dark red with diffuse layers of whitish dense fibrous connective tissue; the heart cavities were enlarged. Microscopically, in 25% of cases, all heart parts had ALλ-CA that was characterized by massive amyloid deposits localized predominantly in the intramyocardial vessel wall, intermuscular connective tissue, and perivascularly. The myocardium also displayed small amyloid deposits of ALλ-CA and ATTR-CA in the intermuscular connective tissue and intramyocardial vessel wall. Amyloid deposits were located in different parts of the myocardium; there were also areas of co-localization of ALλ-CA+ATTR-CA.

CONCLUSION

The combined types of SA occurred under the guise of coronary heart disease and the dilated cardiomyopathy phenotype. The combined amyloid AL-CA and ATTR-CA was generally localized in the interstitium and myocardial vessels. There were also small areas of co-localization of amyloid deposits, which were found mainly in the intramyocardial vessels.

Light Chain Stabilization: A Therapeutic Approach to Ameliorate AL Amyloidosis

Non-native immunoglobulin light chain conformations, including aggregates, appear to cause light chain amyloidosis pathology. Despite significant progress in pharmacological eradication of the neoplastic plasma cells that secrete these light chains, in many patients impaired organ function remains. The impairment is apparently due to a subset of resistant plasma cells that continue to secrete misfolding-prone light chains. These light chains are susceptible to the proteolytic cleavage that may enable light chain aggregation. We propose that small molecules that preferentially bind to the natively folded state of full-length light chains could act as pharmacological kinetic stabilizers, protecting light chains against unfolding, proteolysis and aggregation. Although the sequence of the pathological light chain is unique to each patient, fortunately light chains have highly conserved residues that form binding sites for small molecule kinetic stabilizers. We envision that such stabilizers could complement existing and emerging therapies to benefit light chain amyloidosis patients.

Management of Adverse Events and Supportive Therapy in Relapsed/Refractory Multiple Myeloma

Simple Summary

Multiple myeloma (MM) patients with relapsing and/or refractory (RR) disease are exposed for a prolonged time to multiple drugs, which increase the risk of toxicity. In addition to tumor response, preserving the quality of life represents an important goal for this patient population. Therefore, supportive therapy plays a pivotal role in their treatment by limiting disease- and drug-related complications. The aim of this review is to outline current standards and future strategies to prevent and treat renal insufficiency, anemia, bone disease, and infection, including COVID-19, in RRMM patients. In addition, the incidence and treatment of side effects of novel anti-MM agents will be discussed.

Abstract

Relapsed/refractory (RR) multiple myeloma (MM) patients are a fragile population because of prolonged drug exposure and advanced age. Preserving a good quality of life is of high priority for these patients and the treatment of disease- and treatment-related complications plays a key role in their management. By preventing and limiting MM-induced complications, supportive care improves patients’ outcome. Erythropoietin-stimulating agents and bisphosphonates are well-established supportive strategies, yet novel agents are under investigation, such as anabolic bone agents and activin receptor-like kinase (ALK) inhibitors. The recent dramatic changes in the treatment landscape of MM pose an additional challenge for the routine care of RRMM patients. Multidrug combinations in first and later lines increase the risk for long-lasting toxicities, including adverse cardiovascular and neurological events. Moreover, recently approved first-in-class drugs have unique side-effect profiles, such as ocular toxicity of belantamab mafodotin or gastrointestinal toxicity of selinexor. This review discusses current standards in supportive treatment of RRMM patients, including recommendations in light of the recent SARS-CoV-19 pandemic, and critically looks at the incidence and management of side effects of standard as well as next generation anti-MM agents.

How I Treat AL Amyloidosis

The treatment of patients with systemic light chain (AL) amyloidosis is a challenge to hematologists. Despite its generally small size, the underlying clone causes a rapidly progressing, often devastating multiorgan dysfunction through the toxic light chains that form amyloid deposits. Clinical manifestations are deceitful and too often recognized at an irreversible stage. However, hematologists are in the unique position to diagnose AL amyloidosis at a pre-symptomatic stage checking biomarkers of amyloid organ involvement in patients with monoclonal gammopathies at higher risk to develop the disease. Adequate technology and expertise are needed for a prompt and correct diagnosis, particularly for ruling out non-AL amyloidoses that are now also treatable. Therapy should be carefully tailored based on severity of organ involvement and clonal characteristics, and early and continual monitoring of response is critical. Three recent randomized clinical trials moved AL amyloidosis to evidence-based era. Above all, the daratumumab-bortezomib combination is a new standard-of-care for newly diagnosed patients inducing rapid and deep responses that translate into high rates of organ response. The availability of new effective drugs allows to better personalize the therapy, reduce toxicity, and improve outcomes. Patients should be treated within clinical trials whenever possible.

Protease-sensitive regions in amyloid light chains: what a common pattern of fragmentation across organs suggests about aggregation

Light‐chain (AL) amyloidosis is characterized by deposition of immunoglobulin light chains (LC) as fibrils in target organs. Alongside the full‐length protein, abundant LC fragments are always present in AL deposits. Herein, by combining gel‐based and mass spectrometry analyses, we identified and compared the fragmentation sites of amyloid LCs from multiple organs of an AL λ amyloidosis patient (AL‐55). The positions pinpointed here in kidney and subcutaneous fat, alongside those previously detected in heart of the same patient, were aligned and mapped on the LC’s dimeric and fibrillar states. All tissues contain fragmented LCs along with the full‐length protein; the fragment pattern is coincident across organs, although microheterogeneity exists. Multiple cleavage positions were detected; some are shared, whereas some are organ‐specific, likely due to a complex of proteases. Cleavage sites are concentrated in ‘proteolysis‐prone’ regions, common to all tissues. Several proteolytic sites are not accessible on native dimers, while they are compatible with fibrils. Overall, data suggest that the heterogeneous ensemble of LC fragments originates in tissues and is consistent with digestion of preformed fibrils, or with the hypothesis that initial proteolytic cleavage of the constant domain triggers the amyloidogenic potential of LCs, followed by subsequent proteolytic degradation. This work provides a unique set of molecular data on proteolysis from ex vivo amyloid, which allows discussing hypotheses on role and timing of proteolytic events occurring along amyloid formation and accumulation in AL patients.

Dissecting the Molecular Features of Systemic Light Chain (AL) Amyloidosis: Contributions from Proteomics

Amyloidoses are characterized by aggregation of proteins into highly ordered amyloid fibrils, which deposit in the extracellular space of tissues, leading to organ dysfunction. In AL (amyloid light chain) amyloidosis, the most common form in Western countries, the amyloidogenic precursor is a misfolding-prone immunoglobulin light chain (LC), which, in the systemic form, is produced in excess by a plasma cell clone and transported to target organs though blood. Due to the primary role that proteins play in the pathogenesis of amyloidoses, mass spectrometry (MS)-based proteomic studies have gained an established position in the clinical management and research of these diseases. In AL amyloidosis, in particular, proteomics has provided important contributions for characterizing the precursor light chain, the composition of the amyloid deposits and the mechanisms of proteotoxicity in target organ cells and experimental models of disease. This review will provide an overview of the major achievements of proteomic studies in AL amyloidosis, with a presentation of the most recent acquisitions and a critical discussion of open issues and ongoing trends.

Acute Kidney Injury in Monoclonal Gammopathies

Monoclonal gammopathies (MG) encompass a variety of disorders related to clonal expansion and/or malignant transformation of B lymphocytes. Deposition of free immunoglobulin (Ig) components (light or heavy chains, LC/HC) within the kidney during MG may result over time in multiple types and degrees of injury, including acute kidney injury (AKI). AKI is generally a consequence of tubular obstruction by luminal aggregates of LC, a pattern known as “cast nephropathy”. Monoclonal Ig LC can also be found as intracellular crystals in glomerular podocytes or proximal tubular cells. Proliferative glomerulonephritis with monoclonal Ig deposits is another, less frequent form of kidney injury with a sizable impact on renal function. Hypercalcemia (in turn related to bone reabsorption triggered by proliferating plasmacytoid B cells) may lead to AKI via functional mechanisms. Pharmacologic treatment of MG may also result in additional renal injury due to local toxicity or the tumor lysis syndrome. The present review focuses on AKI complicating MG, evaluating predictors, risk factors, mechanisms of damage, prognosis, and options for treatment.

A nationwide prospective registry of bortezomib-based therapy in light chain (AL) amyloidosis

Until recently, no drug was labeled for AL amyloidosis. In 2011, the Italian Medicines Agency started a program to grant access to upfront bortezomib to patients with AL amyloidosis. All subjects were enrolled in a prospective online registry. Response was evaluated after two cycles to assess the possibility of continuing treatment. A total of 764 patients were included until 2019, and 615 were evaluable. Sixteen percent of patents had advanced (stage-IIIb) heart involvement, and 27% had severe or end-stage renal failure. Bortezomib delivery was possible in stage-IIIb patients at a reduced dose. Bortezomib discontinuation was associated with increasing age, advanced heart involvement and bi-weekly administration. Fifty-nine percent of subjects attained a hematologic response and 14% a cardiac response. Bortezomib-based therapy tends to be discontinued early in elderly patients and in advanced disease. Nevertheless, early response to therapy is possible in this challenging population.

Differences in the characteristics and contemporary cardiac outcomes of patients with light-chain versus transthyretin cardiac amyloidosis

AIMS

To compare the baseline cardiovascular characteristics of immunoglobulin light-chain (AL) and amyloid transthyretin (ATTR) cardiac amyloidosis (CA) and to investigate patients' contemporary cardiac outcomes.

METHODS

Single-center analysis of clinical, laboratory, echocardiographic and cardiac magnetic resonance imaging (CMRi) characteristics of AL and ATTR-CA patients' cohort (years 2013-2020).

RESULTS

Included were 67 CA patients of whom 31 (46%) had AL-CA and 36 (54%) had ATTR-CA. Patients with ATTR-CA versus AL-CA were older (80 (IQR 70, 85) years versus 65 (IQR 60, 71) years, respectively, p<0.001) with male predominance (p = 0.038). Co-morbidities in ATTR-CA patients more frequently included diabetes mellitus (19% versus 3.0%, respectively, p = 0.060) and coronary artery disease (39% versus 10%, respectively, p = 0.010). By echocardiography, patients with ATTR-CA versus AL-CA had a trend to worse left ventricular (LV) ejection function (50 (IQR 40, 55)% versus 60 (IQR 45, 60)%, respectively, p = 0.051), yet comparable LV diastolic function. By CMRi, left atrial area (31 (IQR 27, 36)cm2 vs. 27 (IQR 23, 30)cm2, respectively, p = 0.015) and LV mass index (109 (IQR 96, 130)grams/m2 vs. 82 (IQR 72, 98)grams/m2, respectively, p = 0.011) were increased in patients with ATTR-CA versus AL-CA. Nevertheless, during follow-up (median 20 (IQR 10, 38) months), patients with AL-CA were more frequently admitted with heart failure exacerbations (HR 2.87 (95% CI 1.42, 5.81), p = 0.003) and demonstrated increased mortality (HR 2.51 (95%CI 1.19, 5.28), p = 0.015).

CONCLUSION

Despite the various similarities of AL-CA and ATTR-CA, these diseases have distinct baseline cardiovascular profiles and different heart failure course, thus merit tailored-cardiac management.

Lenalidomide and dexamethasone in relapsed/refractory immunoglobulin light chain (AL) amyloidosis: results from a large cohort of patients with long follow-up

Lenalidomide and dexamethasone (RD) is a standard treatment in relapsed/refractory immunoglobulin light chain (AL) amyloidosis (RRAL). We retrospectively investigated toxicity, efficacy and prognostic markers in 260 patients with RRAL. Patients received a median of two prior treatment lines (68% had been bortezomib-refractory; 33% had received high-dose melphalan). The median treatment duration was four cycles. The 3-month haematological response rate was 31% [very good haematological response (VGHR) in 18%]. The median follow-up was 56·5 months and the median overall survival (OS) and haematological event-free survival (haemEFS) were 32 and 9 months. The 2-year dialysis rate was 15%. VGHR resulted in better OS (62 vs. 26 months, P < 0·001). Cardiac progression predicted worse survival (22 vs. 40 months, P = 0·027), although N-terminal prohormone of brain natriuretic peptide (NT-proBNP) increase was frequently observed. Multivariable analysis identified these prognostic factors: NT-proBNP for OS [hazard ratio (HR) 1·71; P < 0·001]; gain 1q21 for haemEFS (HR 1·68, P = 0·014), with a trend for OS (HR 1·47, P = 0·084); difference between involved and uninvolved free light chains (dFLC) and light chain isotype for OS (HR 2·22, P < 0·001; HR 1·62, P = 0·016) and haemEFS (HR 1·88, P < 0·001; HR 1·59, P = 0·008). Estimated glomerular filtration rate (HR 0·71, P = 0·004) and 24-h proteinuria (HR 1·10, P = 0·004) were prognostic for renal survival. In conclusion, clonal and organ biomarkers at baseline identify patients with favourable outcome, while VGHR and cardiac progression define prognosis during RD treatment.

Amyloidosis of the Urinary Bladder: A Systematic Review and a Proposed Management Algorithm

OBJECTIVE

To propose an algorithm for the management of bladder amyloidosis based on a systematic review of the literature, given that the bladder is the second most commonly affected organ of the urinary tract in the course of systemic or localized amyloidosis.

METHODS

We searched PubMed, Cochrane Library and Scopus databases utilizing PRISMA methodology from inception to November 30, 2020 (PROSPERO: CRD42020207855).

RESULTS

We included 76 studies with 184 patients (9 case series and 67 case reports). Presenting symptoms of bladder amyloidosis comprised of hematuria, irritative or obstructive urinary symptoms, and cystitis-like symptoms. The diagnosis of amyloidosis was established by histologic examination of specimens retrieved during transurethral resection of bladder lesions. Complete endoscopic resection, the cornerstone of management of localized disease, was feasible in 89.1% cases. The included patients were followed up for a mean of 54 months, within which 65 patients (35.3%) recurred. The time to first amyloidosis recurrence was 20 months (range: 1-168). Additionally, 16 individuals presented with concomitant bladder amyloidosis and bladder cancer, while 4 developed bladder malignancy during follow-up. Due to the frequent and early recurrences of patients with bladder amyloidosis, a check-up cystoscopy at 3, 12, and 24 months' after initial resection is recommended. Recurrences should be managed with transurethral resection, while intravesical instillations of dimethyl sulfoxide (DMSO) and cystectomy should be reserved for refractory cases.

CONCLUSION

We propose a management algorithm for bladder amyloidosis based on the available evidence for this rare benign entity that mimics bladder cancer.

Genetic pathogenesis of immunoglobulin light chain amyloidosis: basic characteristics and clinical applications

Immunoglobulin light chain amyloidosis (AL) is an indolent plasma cell disorder characterized by free immunoglobulin light chain (FLC) misfolding and amyloid fibril deposition. The cytogenetic pattern of AL shows profound similarity with that of other plasma cell disorders but harbors distinct features. AL can be classified into two primary subtypes: non-hyperdiploidy and hyperdiploidy. Non-hyperdiploidy usually involves immunoglobulin heavy chain translocations, and t(11;14) is the hallmark of this disease. T(11;14) is associated with low plasma cell count but high FLC level and displays distinct response outcomes to different treatment modalities. Hyperdiploidy is associated with plasmacytosis and subclone formation, and it generally confers a neutral or inferior prognostic outcome. Other chromosome abnormalities and driver gene mutations are considered as secondary cytogenetic aberrations that occur during disease evolution. These genetic aberrations contribute to the proliferation of plasma cells, which secrete excess FLC for amyloid deposition. Other genetic factors, such as specific usage of immunoglobulin light chain germline genes and light chain somatic mutations, also play an essential role in amyloid fibril deposition in AL. This paper will propose a framework of AL classification based on genetic aberrations and discuss the amyloid formation of AL from a genetic aspect.

99mTc-DPD scintigraphy in immunoglobulin light chain (AL) cardiac amyloidosis

Aims

Technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid (^99mTc-DPD scintigraphy) is recognized as highly accurate for the non-invasive diagnosis of transthyretin (ATTR) cardiac amyloidosis (CA). A proportion of patients with immunoglobulin light chain (AL) CA have also been reported to show cardiac ^99mTc-DPD uptake. Herein, we assessed the frequency and degree of cardiac ^99mTc-DPD uptake and its clinical significance among patients with AL CA.

Methods and results

Between 2010 and 2017, 292 consecutive patients with AL CA underwent ^99mTc-DPD scintigraphy and were included in this study: 114 (39%) had cardiac ^99mTc-DPD uptake: grade 1 in 75%, grade 2 in 17%, and grade 3 in 8% of cases. Patients with cardiac ^99mTc-DPD uptake had poorer cardiac systolic function and higher N-terminal pro-brain natriuretic peptide. No differences were noted in cardiac magnetic resonance parameters between patients with and without cardiac ^99mTc-DPD uptake (N = 19 and 42, respectively). Patients with cardiac ^99mTc-DPD uptake showed a trend to worse survival than those with no uptake (log-rank P = 0.056). Among 22 patients who underwent serial ^99mTc-DPD scintigraphy, 5 (23%) showed reduction in the grade of cardiac uptake.

Conclusions

In this large cohort of patients with AL CA, ^99mTc-DPD scintigraphy ∼40% of cases showed cardiac uptake, including grade 2–3 in 10% of all patients (25% of those with cardiac ^99mTc-DPD uptake). Cardiac ^99mTc-DPD uptake was associated with poorer cardiac function and outcomes. These data highlight the critical importance of ruling out AL amyloidosis in all patients with cardiac ^99mTc-DPD uptake to ensure such patients are not assumed to have ATTR CA.

Search for AL amyloidosis risk factors using Mendelian randomization

In amyloid light chain (AL) amyloidosis, amyloid fibrils derived from immunoglobulin light chain are deposited in many organs, interfering with their function. The etiology of AL amyloidosis is poorly understood. Summary data from genome-wide association studies (GWASs) of multiple phenotypes can be exploited by Mendelian randomization (MR) methodology to search for factors influencing AL amyloidosis risk. We performed a 2-sample MR analyzing 72 phenotypes, proxied by 3461 genetic variants, and summary genetic data from a GWAS of 1129 AL amyloidosis cases and 7589 controls. Associations with a Bonferroni-defined significance level were observed for genetically predicted increased monocyte counts (P = 3.8 × 10-4) and the tumor necrosis factor receptor superfamily member 17 (TNFRSF17) gene (P = 3.4 × 10-5). Two other associations with the TNFRSF (members 6 and 19L) reached a nominal significance level. The association between genetically predicted decreased fibrinogen levels may be related to roles of fibrinogen other than blood clotting. be related to its nonhemostatic role. It is plausible that a causal relationship with monocyte concentration could be explained by selection of a light chain-producing clone during progression of monoclonal gammopathy of unknown significance toward AL amyloidosis. Because TNFRSF proteins have key functions in lymphocyte biology, it is entirely plausible that they offer a potential link to AL amyloidosis pathophysiology. Our study provides insight into AL amyloidosis etiology, suggesting high circulating levels of monocytes and TNFRSF proteins as risk factors.

Does protein aggregation drive postmitotic tissue degeneration?

Pharmacological evidence, from clinical trials where patients with systemic amyloid diseases are treated with disease-modifying therapies, supports the notion that protein aggregation drives tissue degeneration in these disorders. The protein aggregate structures driving tissue pathology and the commonalities in etiology between these diseases and Alzheimer's disease are under investigation.

Conventional physical examination extended by bedside ultrasound: a new paradigm in nephrological practice

Point-of-Care Ultrasound (POCUS) has been gaining momentum as an extension to physical examination in several specialties. In nephrology, POCUS has generally been used in a restricted way in urinary tract evaluation. We report the case of a patient with nephrotic syndrome secondary to amyloidosis, previously diagnosed by renal biopsy, who was oligosymptomatic when seen the an outpatient clinic, where the POCUS, focused on the heart, lung and abdomen, revealed anasarca, pulmonary congestion and cardiac changes suggestive of cardiac amyloidosis. After evaluation by the cardiology and hematology services, the diagnosis of AL amyloidosis with cardiac involvement was confirmed. This case emphasizes the importance of extending the physical examination using POCUS, which, ideally, should not be restricted to the urinary tract.

Daratumumab-Based Treatment for Immunoglobulin Light-Chain Amyloidosis

BACKGROUND

Systemic immunoglobulin light-chain (AL) amyloidosis is characterized by deposition of amyloid fibrils of light chains produced by clonal CD38+ plasma cells. Daratumumab, a human CD38-targeting antibody, may improve outcomes for this disease.

METHODS

We randomly assigned patients with newly diagnosed AL amyloidosis to receive six cycles of bortezomib, cyclophosphamide, and dexamethasone either alone (control group) or with subcutaneous daratumumab followed by single-agent daratumumab every 4 weeks for up to 24 cycles (daratumumab group). The primary end point was a hematologic complete response.

RESULTS

A total of 388 patients underwent randomization. The median follow-up was 11.4 months. The percentage of patients who had a hematologic complete response was significantly higher in the daratumumab group than in the control group (53.3% vs. 18.1%) (relative risk ratio, 2.9; 95% confidence interval [CI], 2.1 to 4.1; P<0.001). Survival free from major organ deterioration or hematologic progression favored the daratumumab group (hazard ratio for major organ deterioration, hematologic progression, or death, 0.58; 95% CI, 0.36 to 0.93; P = 0.02). At 6 months, more cardiac and renal responses occurred in the daratumumab group than in the control group (41.5% vs. 22.2% and 53.0% vs. 23.9%, respectively). The four most common grade 3 or 4 adverse events were lymphopenia (13.0% in the daratumumab group and 10.1% in the control group), pneumonia (7.8% and 4.3%, respectively), cardiac failure (6.2% and 4.8%), and diarrhea (5.7% and 3.7%). Systemic administration-related reactions to daratumumab occurred in 7.3% of the patients. A total of 56 patients died (27 in the daratumumab group and 29 in the control group), most due to amyloidosis-related cardiomyopathy.

CONCLUSIONS

Among patients with newly diagnosed AL amyloidosis, the addition of daratumumab to bortezomib, cyclophosphamide, and dexamethasone was associated with higher frequencies of hematologic complete response and survival free from major organ deterioration or hematologic progression. (Funded by Janssen Research and Development; ANDROMEDA ClinicalTrials.gov number, NCT03201965.).

From Clinical Clues to Final Diagnosis: The Return of Detective Work to Clinical Medicine in Cardiac Amyloidosis

Cardiac amyloidosis is frequently misdiagnosed, denying patients the opportunity for timely and appropriate management of the disease. The purpose of this review and case studies is to raise awareness of the diagnostic "red flags" associated with cardiac amyloidosis and the currently available non-invasive strategies for diagnosis. The review focuses on the identification of one of the two main types of cardiac amyloidosis, transthyretin amyloid cardiomyopathy, and non-invasive tools to distinguish this from light-chain amyloidosis. A diagnostic algorithm centered around the use of non-invasive imaging and laboratory analysis is presented. The algorithm generates four differential diagnoses for patients presenting with signs and symptoms consistent with cardiac amyloidosis. Case examples are presented, representing the four potential outcomes of diagnosis using the algorithm. The review provides a guide on how to recognize the often-overlooked presentations of this disease in clinical practice. Non-invasive imaging techniques and diagnostic tools that do not require the involvement of a specialty center have allowed for the improved diagnosis of cardiac amyloidosis. Timely diagnosis of this life-threatening disease is essential for optimal management and it is imperative that clinicians have a high index of suspicion for patients presenting with "red flag" symptoms.

Tumor cells in light-chain amyloidosis and myeloma show different transcriptional rewiring of normal plasma cell development

Although light-chain amyloidosis (AL) and multiple myeloma (MM) are characterized by tumor plasma cell (PC) expansion in bone marrow (BM), their clinical presentation differs. Previous attempts to identify unique pathogenic mechanisms behind such differences were unsuccessful, but there are no studies investigating the differentiation stage of tumor PCs in patients with AL and MM. We sought to define a transcriptional atlas of normal PC development (n=11) in secondary lymphoid organs (SLO), peripheral blood (PB) and BM for comparison with the transcriptional programs (TPs) of tumor PCs in AL (n=37), MM (n=46) and MGUS (n=6). Based on bulk and single-cell RNAseq, we observed thirteen TPs during transition of normal PCs throughout SLO, PB and BM; that CD39 outperforms CD19 to discriminate new-born from long-lived BM-PCs; that tumor PCs expressed the most advantageous TPs of normal PC differentiation; that AL shares greater similarity to SLO-PCs whereas MM is transcriptionally closer to PB-PCs and new-born BM-PCs; that AL and MM patients enriched in immature TPs had inferior survival; and that TPs related with protein N-linked glycosylation are upregulated in AL. Collectively, we provide a novel resource to understand normal PC development and the transcriptional reorganization of AL and other monoclonal gammopathies.

Diagnostic delay and characterization of the clinical prodrome in AL amyloidosis among 1523 US adults diagnosed between 2001 and 2019

Light-chain (AL) amyloidosis is a multisystem disorder with a high early mortality and diagnostic delays of >1 year from symptom onset. This retrospective observational study sought to characterize the clinical prodrome and diagnostic delay to inform early detection. We identified 1523 adults with newly diagnosed AL amyloidosis in the Optum de-identified Clinformatics^® Datamart US healthcare claims database as those with ≥2 new diagnosis codes for AL or other amyloidosis in 90 days with ≥1 multiple myeloma treatment within 730 days, excluding patients with prior hereditary or secondary amyloidosis and Familial Mediterranean Fever. We considered 34 signs/symptoms using diagnosis codes in all observable time on or before AL amyloidosis diagnosis. Sign/symptom prevalence was compared to that of 1:4 matched population controls. The overlap and sequence of signs/symptoms and the median time from first sign/symptom to AL amyloidosis diagnosis were explored. Healthcare utilization was summarized. The most common individual AL amyloidosis signs/symptoms were malaise/fatigue (61%) and dyspnea (59%). Cardiac signs/symptoms were observed in 77% of patients, followed by renal (62%) and neurologic (59%) signs/symptoms. Multisystem involvement (≥3 systems) was present in 54%. Monoclonal gammopathy was detected in 29% before diagnosis. Median time from symptom onset to AL amyloidosis diagnosis was 2.7 years. Healthcare utilization was high between first AL amyloidosis signs/symptoms and diagnosis, with 50% visiting ≥5 physician types. AL amyloidosis patients have a lengthy and complex clinical prodrome. Novel approaches to early diagnosis are needed to improve outcomes.

Barriers to Small Molecule Drug Discovery for Systemic Amyloidosis

Inhibition of amyloid fibril formation could benefit patients with systemic amyloidosis. In this group of diseases, deposition of amyloid fibrils derived from normally soluble proteins leads to progressive tissue damage and organ failure. Amyloid formation is a complex process, where several individual steps could be targeted. Several small molecules have been proposed as inhibitors of amyloid formation. However, the exact mechanism of action for a molecule is often not known, which impedes medicinal chemistry efforts to develop more potent molecules. Furthermore, commonly used assays are prone to artifacts that must be controlled for. Here, potential mechanisms by which small molecules could inhibit aggregation of immunoglobulin light-chain dimers, the precursor proteins for amyloid light-chain (AL) amyloidosis, are studied in assays that recapitulate different aspects of amyloidogenesis in vitro. One molecule reduced unfolding-coupled proteolysis of light chains, but no molecules inhibited aggregation of light chains or disrupted pre-formed amyloid fibrils. This work demonstrates the challenges associated with drug development for amyloidosis, but also highlights the potential to combine therapies that target different aspects of amyloidosis.

Machine learning analyses of antibody somatic mutations predict immunoglobulin light chain toxicity

In systemic light chain amyloidosis (AL), pathogenic monoclonal immunoglobulin light chains (LC) form toxic aggregates and amyloid fibrils in target organs. Prompt diagnosis is crucial to avoid permanent organ damage, but delayed diagnosis is common because symptoms usually appear only after strong organ involvement. Here we present LICTOR, a machine learning approach predicting LC toxicity in AL, based on the distribution of somatic mutations acquired during clonal selection. LICTOR achieves a specificity and a sensitivity of 0.82 and 0.76, respectively, with an area under the receiver operating characteristic curve (AUC) of 0.87. Tested on an independent set of 12 LCs sequences with known clinical phenotypes, LICTOR achieves a prediction accuracy of 83%. Furthermore, we are able to abolish the toxic phenotype of an LC by in silico reverting two germline-specific somatic mutations identified by LICTOR, and by experimentally assessing the loss of in vivo toxicity in a Caenorhabditis elegans model. Therefore, LICTOR represents a promising strategy for AL diagnosis and reducing high mortality rates in AL.

The role of induction therapy before autologous stem cell transplantation in low disease burden AL amyloidosis patients

BACKGROUND

Induction therapy is recommended before autologous stem cell transplantation (ASCT) for AL amyloidosis patients with high disease burden [bone marrow plasma cells (BMPCs) > 10%], but the role of induction therapy before ASCT in patients with low disease burden (BMPCs ≤ 10%) is still unknown.

METHODS

A total of 227 patients with AL amyloidosis were included in this study. Among 227 patients, 124 patients received bortezomib-based induction prior to ASCT and were defined as group A, 35 patients received other chemotherapeutic induction and were defined as group B, and the other 68 patients without induction were defined as group C. We compared the differences of efficacy and prognosis between the three groups.

RESULTS

The haematological overall response rates (ORR) of groups A, B and C were 91%, 67% and 75%, respectively. The complete response rates (CR) of groups A, B and C were 50%, 25% and 20%, respectively. Both the ORR and CR rates of group A were significantly higher than those of groups B and C. The renal response rates of groups A, B and C were 64%, 46% and 47%, respectively. The cardiac response rates of groups A, B and C were 74%, 45% and 40%, respectively. The renal and cardiac responses rates of group A were also significantly higher than those of the other two groups. After a median follow-up of 44 months, the median OS was not reached. The 5-year estimated overall survival (OS) rates of groups A, B and C were 81%, 57% and 67%, respectively. The median progression-free survival (PFS) was 83 months for all patients. The 5-year estimated PFS rates of groups A, B and C were 61%, 38% and 49%, respectively. Both the OS and PFS of group A were higher than those of both group B and group C. On multivariate analysis, baseline dFLC > 50 mg/L was associated with worse survival, but induction with bortezomib was associated with better survival.

CONCLUSION

Our study demonstrated that low disease burden AL patients who are eligible for ASCT may benefit from bortezomib-based induction therapy.

Acquired and inherited amyloidosis: Knowledge driving patients' care

Until recently, systemic amyloidoses were regarded as ineluctably disabling and life-threatening diseases. However, this field has witnessed major advances in the last decade, with significant improvements in therapeutic options and in the availability of accurate and non-invasive diagnostic tools. Outstanding progress includes unprecedented hematological response rates provided by risk-adapted regimens in light chain (AL) amyloidosis and the approval of innovative pharmacological agents for both hereditary and wild-type transthyretin amyloidosis (ATTR). Moreover, the incidence of secondary (AA) amyloidosis has continuously reduced, reflecting advances in therapeutics and overall management of several chronic inflammatory diseases. The identification and validation of novel therapeutic targets has grounded on a better knowledge of key molecular events underlying protein misfolding and aggregation and on the increasing availability of diagnostic, prognostic and predictive markers of organ damage and response to treatment. In this review, we focus on these recent advancements and discuss how they are translating into improved outcomes. Neurological involvement dominates the clinical picture in transthyretin and gelsolin inherited amyloidosis and has a significant impact on disease course and management in all patients. Neurologists, therefore, play a major role in improving patients' journey to diagnosis and in providing early access to treatment in order to prevent significant disability and extend survival.

Treatment of AL Amyloidosis: Mayo Stratification of Myeloma and Risk-Adapted Therapy (mSMART) Consensus Statement 2020 Update

Immunoglobulin light chain (AL) amyloidosis is a clonal plasma cell disorder leading to progressive and life-threatening organ failure. The heart and the kidneys are the most commonly involved organs, but almost any organ can be involved. Because of the nonspecific presentation, diagnosis delay is common, and many patients are diagnosed with advanced organ failure. In the era of effective therapies and improved outcomes for patients with AL amyloidosis, the importance of early recognition is further enhanced as the ability to reverse organ dysfunction is limited in those with a profound organ failure. As AL amyloidosis is an uncommon disorder and given patients' frailty and high early death rate, management of this complex condition is challenging. The treatment of AL amyloidosis is based on various anti-plasma cell therapies. These therapies are borrowed and customized from the treatment of multiple myeloma, a more common disorder. However, a growing number of phase 2/3 studies dedicated to the AL amyloidosis population are being performed, making treatment decisions more evidence-based. Supportive care is an integral part of management of AL amyloidosis because of the inherent organ dysfunction, limiting the delivery of effective therapy. This extensive review brings an updated summary on the management of AL amyloidosis, sectioned into the 3 pillars for survival improvement: early disease recognition, anti-plasma cell therapy, and supportive care.

Negative Fat Pad Biopsy in Systemic AL: A Case Report Analyzing the Preferred Amyloidosis Screening Test

Light chain amyloidosis (AL) causes irreversible multi-organ damage if not diagnosed early in the disease process. Fat pad biopsy is thought to be a highly sensitive screening test in systemic AL cases, especially if greater than three organs are involved. We present a case of a 64-year-old female who was admitted to the hospital with worsening heart and kidney failure, anasarca, increased free serum lambda light chains, and a negative fat pad biopsy for amyloidosis. Later, she developed asystole, bradycardia, severe hypotension, and respiratory distress. Because X-rays of her calvarium showed multiple osteolytic lesions, a bone marrow biopsy was planned to assess for multiple myeloma. Due to her non-reassuring vitals, the biopsy was not attempted, and she passed away several weeks later. Autopsy findings identified the cause of death as multiple system organ failure due to systemic AL. Through microscopic examination, pathologists found amyloid deposits in her heart, kidneys, rectum, thyroid, adrenals, bone marrow, liver, and spleen. Postmortem fat pad biopsy was negative; however, bone marrow biopsy demonstrated clusters of CD138-positive cells, confirming plasma cell dyscrasia. In cases with a negative fat pad biopsy, an additional superficial or involved organ biopsy should be pursued to establish a diagnosis of amyloidosis if strong clinical suspicion exists.

Predictors and outcomes of acute kidney injury during autologous stem cell transplantation in AL amyloidosis

BACKGROUND

Acute kidney injury (AKI) is a common complication after high dose melphalan and autologous stem cell transplantation (HDM/SCT) in patients with AL amyloidosis. However, its incidence, predictors and outcomes are not well known.

METHODS

This observational study included 223 patients with AL amyloidosis who underwent HDM/SCT. AKI was defined as an increase in serum creatinine to ≥ 1.5 times the baseline occurring within the first 30 days of HDM/SCT.

RESULTS

The median age was 58 years (range: 30-77). Kidney and cardiac involvement were present in 86.1% and 56.8%, respectively. The median eGFR was 83.5 mL/min/1.73m2 (range: 9-213) and proteinuria was 2,899 mg/24 h (range: 0-19,966). AKI occurred in 29.1% of patients. Dialysis was initiated in 15 patients (6.7%) and of these 12 (80%) were able to discontinue dialysis. Most of the episodes of AKI occurred within the first 2 weeks. With a median follow-up of 4.5 years (range: 0.1-16.5), AKI was associated with increased overall mortality, HR 4.53 (95%CI [2-10.23]). The 10-year overall survival (OS) was 87.1% without AKI, versus 56.9% with AKI. AKI was also associated with an increased risk for end stage kidney disease (ESKD), HR 4.6 (95%CI [1.44-14.38]). The risk of developing ESKD at 10-year was 18.9% with AKI, versus 8.1% without AKI. Several risk factors were found and using multivariate logistic regression, a prediction model was developed which included 3 readily available variables: eGFR<60 mL/min/1.73m2, IVSd>12mm, and albumin<3 g/dL. This model was able to predict AKI development with an AUC of 0.8.

CONCLUSIONS

AKI is common in the post-HDM/SCT period and it leads to increased risk for ESKD and death. Our prediction model is an easily deployable tool in clinical settings as part of the discussion with patients who are being prepared for HDM/SCT.

Sequential response-driven bortezomib-based therapy followed by autologous stem cell transplant in AL amyloidosis

Autologous stem cell transplant (ASCT) is highly effective in selected patients with light chain (AL) amyloidosis. Bortezomib, preceding or following ASCT, improves responses. Satisfactory responses, including at least a partial response, very good partial response (VGPR) with organ response, or complete response, can be observed after induction therapy alone. We report 139 patients treated upfront with cyclophosphamide/bortezomib/dexamethasone (CyBorD), followed by ASCT only if response was unsatisfactory. Only 1 treatment-related death was observed. After CyBorD, hematologic response (HR) rate was 68% (VGPR or better, 51%), with 45% satisfactory responses. Transplant was performed in 55 (40%) subjects and resulted in an 80% HR rate (65% ≥ VGPR). Five-year survival was 86% and 84% in patients treated with ASCT or CyBorD alone, respectively (P = .438). Also, 6- and 12- month landmark analyses did not show differences in survival. Duration of response was not different in the 2 groups (60 vs 49 months; P = .670). Twenty-one (15%) patients with an unsatisfactory response to CyBorD could not undergo ASCT because of ineligibility or refusal; instead, they received rescue chemotherapy, with HR in 38% of cases and 51% 5-year survival. This sequential response-driven approach, offering ASCT to patients who do not attain satisfactory response to upfront CyBorD, is very safe and effective in AL amyloidosis.

Assessment of minimal residual disease using multiparametric flow cytometry in patients with AL amyloidosis

Despite achieving a hematologic complete response after treatment, many patients with AL amyloidosis do not attain recovery of organ function and/or experience hematologic relapse. A persistent plasma cell clone producing amyloidogenic light chains at levels below the detection threshold of traditional serologic methods is hypothesized to impede organ response in some patients. Assessment of minimal residual disease (MRD) may therefore have clinical importance as a more stringent treatment response tool for patients in a hematologic complete response. We used 2-tube, 10-color combination multiparametric flow cytometry to assess for MRD at a minimum sensitivity of 1 in 105 nucleated cells. Of 65 patients in hematologic complete response, 36 (55%) were found to have a residual clonal plasma cell population in the bone marrow. Comparing the MRD-negative and MRD-positive groups, renal response was observed in 88% vs 64% (P = .06), cardiac response in 75% vs 59% (P = .45), and any organ response in 90% vs 75% (P = .20) of patients. Depth of organ response as measured by the percent decrease in 24-hour proteinuria and brain natriuretic peptide was 96% vs 91% (P = .16) and 55% vs 46% (P = .66), respectively. These data suggest a possible correlation between MRD negativity and higher probability of organ response after treatment in AL amyloidosis. Future prospective studies with a larger cohort are needed to determine the clinical relevance of these improvements. This trial was registered at www.clinicaltrials.gov as #NCT00898235.