Immunoglobulin light chain amyloidosis: 2020 update on diagnosis, prognosis, and treatment

Fixed duration vs. prolonged duration treatment after first line therapy in patients with systemic light chain amyloidosis

BACKGROUND

The main objective of treatment in systemic light chain amyloidosis (AL amyloidosis) is to achieve the best hematological response. Deeper responses are associated with better organ responses and survival. In this study, we analysed the efficacy of prolonged duration treatment after first line in patients with AL amyloidosis.

METHODS

Retrospective analysis that included patients older than 18 years with AL amyloidosis. We excluded patients with more than 30% marrow plasmacytosis or concurrent multiple myeloma. Two cohorts identified accordingly if they received or not prolonged treatment after the first line. Survival analysis regarding progression free survival (PFS) and overall survival (OS) estimated with Kaplan-Meier and comparisons between groups with log-rank.

RESULTS

Thirty-eight patients were included in the analysis with a median age of 55 years. Twenty-one patients received prolonged duration treatment and 17 did not. In the prolonged duration group, after a median duration of 12 months, the median PFS was 58.8 months. In the fixed duration treatment group, PFS was 30.6 months. The difference was significant with p = .0045 favouring prolonged duration treatment. Organ response was sustained for a longer period in the prolonged duration treatment group. For OS, the difference was not significant.

CONCLUSIONS

Prolonged duration treatment in patients with systemic light chain amyloidosis correlated with better PFS and deeper organ responses. Prospective studies are needed to analyse this further.

Monoclonal Gammopathy-Related Kidney Diseases

Monoclonal gammopathies occur secondary to a broad range of clonal B lymphocyte or plasma cell disorders, producing either whole or truncated monoclonal immunoglobulins. The kidneys are often affected by these monoclonal proteins, and, although not mutually exclusive, can involve the glomeruli, tubules, interstitium, and vasculature. The nephrotoxic potential of these monoclonal proteins is dependent on a variety of physicochemical characteristics that are responsible for the diverse clinicopathologic manifestations, including glomerular diseases with organized deposits, glomerular diseases with granular deposits, and other lesions, such as C3 glomerulopathy and thrombotic microangiopathy with unique pathophysiologic features. The diseases that involve primarily the tubulointerstitial and vascular compartments are light chain cast nephropathy, light chain proximal tubulopathy, crystal-storing histiocytosis, and crystalglobulin-induced nephropathy with distinct acute and chronic clinicopathologic features. The diagnosis of a monoclonal gammopathy-related kidney disease is established by identification of an underlying active or more commonly, low-grade hematologic malignancy, serologic evidence of a monoclonal gammopathy when detectable, and most importantly, monoclonal protein-induced pathologic lesions seen in a kidney biopsy, confirming the association with the monoclonal protein. Establishing a diagnosis may be challenging at times, particularly in the absence of an overt hematologic malignancy, with or without monoclonal gammopathy, such as proliferative glomerulonephritis with monoclonal immunoglobulin deposits. Overall, the treatment is directed against the underlying hematologic disorder and the potential source of the monoclonal protein.

Systematic literature review of evidence in amyloid light-chain amyloidosis

Introduction: Treatment of amyloid light-chain (AL) amyloidosis, a rare disease with a <5-year lifespan, remains challenging. This systematic literature review (SLR) aimed to evaluate the current evidence base in AL amyloidosis. Methods: Literature searches on clinical, health-related quality of life, economic and resource use evidence were conducted using the Embase, MEDLINE and Cochrane databases as well as gray literature. Results: This SLR yielded 84 unique studies from: five randomized controlled trials; 54 observational studies; 12 health-related quality of life studies, none with utility values; no economic evaluation studies; and 16 resource use studies, none with indirect costs. Conclusion: This SLR highlights a paucity of published literature relating to randomized controlled trials, utility values, economic evaluations and indirect costs in AL amyloidosis.

[Efficacy and safety of daratumumab in the treatment of advanced light chain amyloidosis]

Objective: The study investigated the efficacy and safety of daratumumab in the treatment of cardiac light chain (AL) amyloidosis. Methods: We retrospectively analyzed the clinical characteristics, hematologic response, organ response, long-term survival, and adverse events of 20 patients with newly diagnosed or relapsed/refractory cardiac AL amyloidosis treated with daratumumab in Peking Union Medical College Hospitalo from January 2017 to March 2021. Results: The overall median age of 20 patients was 62 (range, 45-73) yeas, with a male to female ratio of 2.3:1. Nine patients were newly diagnosed, while 11 patients had relapsed or refractory disease. Based on Mayo 2004 cardiac AL staging system, stages Ⅱ and Ⅲ diseases were present in 20 patients respectively. Four patients died during the first cycle of daratumumab, and the remaining 16 patients completed a median of 3 (range, 1-10) cycles of treatment. Overall hematologic response rates were 80% each at 1, 3, and 6 months after treatment initiation, and 45% , 60% , and 60% of the patients achieved at least a very good partial response at 1, 3, and 6 months respectively. The median duration to hematologic response was 13 (range, 6-28) days. At 3, 6, and 12 months, 20% , 30% , and 40% of the patients respectively achieved a cardiac response, and the median days to response was 91 (range, 30-216) days. As of the last follow-up, 9 (45% ) patients died. The 1-month mortality rate of all the patients and stage IIIb patients was 25% and 40% , respectively. The 1-year overall survival rate was 48.4% . Lymphocytopenia was the most common hematological adverse event (above grade 3) . Non-hematological adverse events were mainly infusion-related reactions and infections. Conclusion: Daratumumab could induce deep and rapid hematologic response in newly diagnosed and previously treated cardiac AL amyloidosis patients. However, daratumumab was not effective in preventing the high and early mortality rate in stage Ⅲb patients.

Dynamic protein structures in normal function and pathologic misfolding in systemic amyloidosis

Dynamic and disordered regions in native proteins are often critical for their function, particularly in ligand binding and signaling. In certain proteins, however, such regions can contribute to misfolding and pathologic deposition as amyloid fibrils in vivo. For example, dynamic and disordered regions can promote amyloid formation by destabilizing the native structure, by directly triggering the aggregation, by promoting protein condensation, or by acting as sites of early proteolytic cleavage that favor a release of aggregation-prone fragments or facilitate fibril maturation. At the same time, enhanced dynamics in the native protein state accelerates proteolytic degradation that counteracts amyloid accumulation in vivo. Therefore, the functional need for dynamic protein regions must be balanced against their inherently labile nature. How exactly this balance is achieved and how is it shifted upon amyloidogenic mutations or post-translational modifications? To illustrate possible scenarios, here we review the beneficial and pathologic roles of dynamic and disordered regions in the native states of three families of human plasma proteins that form amyloid precursors in systemic amyloidoses: immunoglobulin light chain, apolipoproteins, and serum amyloid A. Analysis of structure, stability and local dynamics of these diverse proteins and their amyloidogenic variants exemplifies how disordered/dynamic regions can provide a functional advantage as well as an Achilles heel in pathologic amyloid formation.

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.

Peritoneal Dialysis Failure and its Impact on Holistic Kidney Care: A Case Report

Introduction

Peritonitis remains the primary cause of treatment failure among patients with end-stage kidney disease on continuous ambulatory peritoneal dialysis. However, detailed case analyses illustrating the application of current research in clinical practice remain scant. This case report aimed to elucidate the roles of dialysis nurses in a hospital setting in the management of a 62-year-old male patient with a history of kidney failure secondary to amyloidosis.

Case Presentation

The patient was diagnosed with continuous ambulatory peritoneal dialysis-associated peritonitis.

Management and Outcomes

Dialysis nurses applied evidence-based practices in the management of the patient’s exit-site infection, imbalanced nutrition, and psychosocial concerns. The patient was discharged after 7 days, with a comprehensive treatment regimen, including an individualized peritoneal dialysis protocol adjusted to his daily schedules, education on self-care techniques, and continual nutritional management to prevent recurrence and improve his overall health. This case report shows that admissions for continuous ambulatory peritoneal dialysis-associated peritonitis require evidence-based nursing interventions specific to, and geared toward, each patient’s prioritized health problems.

Discussion

Peritonitis cases are preventable with appropriate nursing interventions that can lower the chance of treatment failure and long-term impact caused by an abrupt switch to hemodialysis. To successfully manage patients with continuous ambulatory peritoneal dialysis-associated peritonitis, dialysis nurses should appreciate the intricacies of the analyses underpinning their professional practices in promoting the patient’s self-care techniques.

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.

Dissection of the amyloid formation pathway in AL amyloidosis

In antibody light chain (AL) amyloidosis, overproduced light chain (LC) fragments accumulate as fibrils in organs and tissues of patients. In vitro, AL fibril formation is a slow process, characterized by a pronounced lag phase. The events occurring during this lag phase are largely unknown. We have dissected the lag phase of a patient-derived LC truncation and identified structural transitions that precede fibril formation. The process starts with partial unfolding of the V_L domain and the formation of small amounts of dimers. This is a prerequisite for the formation of an ensemble of oligomers, which are the precursors of fibrils. During oligomerization, the hydrophobic core of the LC domain rearranges which leads to changes in solvent accessibility and rigidity. Structural transitions from an anti-parallel to a parallel β-sheet secondary structure occur in the oligomers prior to amyloid formation. Together, our results reveal a rate-limiting multi-step mechanism of structural transitions prior to fibril formation in AL amyloidosis, which offers, in the long run, opportunities for therapeutic intervention.

AL amyloidosis is caused by the accumulation of overproduced light chain (LC) fragments as fibrils in patient organs and it is the most prevalent systemic amyloidosis. Here, the authors combine biochemical and biophysical experiments to characterise the lag phase of a patient-derived truncated LC and they identify structural transitions that precede fibril formation.

A real-world study on diagnosis and prognosis of light-chain cardiac amyloidosis in Southern China

Background

Light-chain cardiac amyloidosis (AL-CA) has been highly valued in developed countries, but in developing countries, the recognition and diagnosis of this condition is still limited. There are currently few reports on a large number of Chinese patients with AL-CA. The present study aimed to report real-world clinical characteristics and prognosis of AL-CA in China.

Methods and results

Consecutive patients with AL-CA diagnosed at the Second Xiangya Hospital of Central South University between June 2012 and September 2020 were reviewed. A total of 170 patients with AL-CA have been recruited, whose mean ages were 60.81 ± 10.46. 70.59% of the patients were male. They were from eight provinces in southern China, 55.7% were referred patients, and 37.3% had been misdiagnosed previously. 64 (37.6%) patients received chemotherapy. The median survival time for patients with AL-CA was 8.00 months, and survival time for patients who received chemotherapy was 13.00 months, which was significantly longer than that of patients with palliative treatment (13.00 vs 6.00, p = 0.004).

Conclusions

Although clinicians have improved their understanding of AL-CA in recent years, the prognosis of AL-CA is still poor, and the misdiagnosis rate and missed diagnosis rate are still very high in China. It is imperative to improve the recognition and early diagnosis of this condition, which may require multidisciplinary collaboration among cardiologists, hematologists and nephrologists.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02256-3.

A prognostic staging system for light-chain amyloidosis using hepatic and renal indicator data from 1,064 Chinese patients

Background

Light-chain (AL) amyloidosis frequently involves severe multiple end-organ damage, thus affecting prognosis. As the current disease staging system is based only on cardiac indicators, we propose a new staging system based on multiple organ indicators to supplement the existing system.

Methods

Patients with AL amyloidosis (n=1,064) from 18 Chinese hospitals were enrolled and divided into test and validation cohorts (4:1). Multivariate analyses were performed to identify the clinical and laboratory factors for inclusion in the new staging system.

Results

A score of 1 was assigned for each of the following-the difference between the involved and uninvolved free light chains ≥100 mg/L, estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², total bilirubin (Tbil) ≥18 µmol/L, cardiac troponin I ≥0.06 µg/L, and N-terminal pro-brain natriuretic peptide (NT-proBNP) ≥3,600 pg/mL-to divide the patients into five disease stages (0 to IV). There were 220 (20.7%), 291 (27.3%), 251 (23.6%), 178 (16.7%), and 124 (11.7%) patients with stage 0, I, II, III, and IV disease, respectively. Patients with stage II, III, and IV disease had a median overall survival (OS) of 56.9 months [95% confidence interval (CI), 33.9-not reached (NR)], 18.6 months (95% CI, 33.9-NR), and 6.5 months (95% CI, 8.0-24.6) (P<0.001), respectively. The 3-year survival estimates for patients with stages 0, I, II, III, and IV were 90.7%, 71.4%, 59.4%, 39.0%, and 22.1%, respectively.

Conclusions

The new staging system has been developed that incorporates plasma cell-related characteristics in addition to cardiac, renal, and hepatic function parameters. It enhances the risk stratification of patients with AL amyloidosis and is useful when multiple organs are involved.

Paraproteinemia and neuropathy

Paraproteinemia is associated with different peripheral neuropathies. The major causes of neuropathy correlated with paraproteinemia are the deposition of immunoglobulin in the myelin, represented by anti-myelin-associated glycoprotein (MAG) neuropathy; deposition of immunoglobulin or its fragment in the interstitium, represented by immunoglobulin light chain amyloidosis (AL amyloidosis); and paraneoplastic mechanisms that cannot be solely attributed to the deposition of immunoglobulin or its fragment, represented by polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin change (POEMS) syndrome. Patients with anti-MAG neuropathy and POEMS syndrome present with slowing of nerve conduction parameters. This characteristic fulfills the electrodiagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) defined by the European Academy of Neurology and Peripheral Nerve Society (EAN/PNS). Although direct damage caused by the deposition of amyloid can induce axonal damage in AL amyloidosis, some patients with this condition have features fulfilling the EAN/PNS electrodiagnostic criteria for CIDP. Conventional immunotherapies for CIDP, such as steroids, intravenous immunoglobulin, and plasma exchange, offer no or only minimal-to-modest benefit. Although rituximab can reduce the level of circulating autoantibodies, it may only be effective in some patients with anti-MAG neuropathy. Drugs including melphalan, thalidomide, lenalidomide, and bortezomib for POEMS syndrome and those including melphalan, thalidomide, lenalidomide, pomalidomide, bortezomib, ixazomib, and daratumumab for AL amyloidosis are considered. Since there will be more therapeutic options in the future, thereby enabling appropriate treatments for individual neuropathies, there is an increasing need for early diagnosis.

Doxycycline Combined With Bortezomib-Cyclophosphamide-Dexamethasone Chemotherapy for Newly Diagnosed Cardiac Light-Chain Amyloidosis: A Multicenter Randomized Controlled Trial

Background: Doxycycline was demonstrated in a retrospective study to be associated with greater survival in patients with light chain (AL) amyloidosis. Therefore, we prospectively compared the efficacy of bortezomib-cyclophosphamide-dexamethasone (CyBorD) and CyBorD combined with doxycycline for cardiac AL amyloidosis. Methods: This was a multicenter, open-label randomized controlled trial. Patients with Mayo 2004 stage II-III AL amyloidosis were included. Patients were randomized to doxycycline 100 mg twice daily along with 9 cycles of CyBorD (doxycycline group) or to 9 cycles of CyBorD alone (control group). The primary outcome was 2-year progression-free survival (PFS). PFS was defined as the time from randomization to death, hematologic progression or organ progression (heart, kidney or liver). Hematologic progression was defined based on substantial increase in free light chain. Increase in either N-terminal pro B-type natriuretic peptide or cardiac troponin was the main criterion for defining cardiac progression. Cardiac PFS, defined as the time from randomization to cardiac progression or death, was compared between groups in an exploratory analysis. The corresponding treatment hazard ratio was estimated using a Cox regression model. Results: 140 patients underwent randomization, with 70 in each group. The median age was 61 (range, 33-78) years with a male: female ratio of 1.75:1. Stage II disease was present in 34 (48.6%) and 33 (47.1%) patients in the doxycycline and control groups, respectively. After a median follow-up duration of 24.4 months, 32/70 (45.7%) of patients in the doxycycline group and 30/70 (42.9%) of patients in the control group experienced progression. PFS was not significantly different between groups (hazard ratio 0.97, 95% CI, 0.59-1.60, p=0.91). Cardiac progression occurred in 29/70 (41.4%) of patients in the doxycycline group and 26/70 (37.1%) of patients in the control group. The death rates for both groups by the end of follow-up was the same, 25/70 (35.7%). There were no significant differences observed for either cardiac PFS (hazard ratio 0.91, 95% CI, 0.54-1.55, p=0.74) or overall survival (hazard ratio 1.04, 95% CI, 0.60-1.81, p=0.89). Conclusions: Our trial demonstrated that doxycycline combined with CyBorD failed to prolong PFS or cardiac PFS compared with CyBorD alone in cardiac AL amyloidosis. Clinical Trial Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT03401372.

The Ultrastructure of Tissue Damage by Amyloid Fibrils

Amyloidosis is a group of diseases that includes Alzheimer’s disease, prion diseases, transthyretin (ATTR) amyloidosis, and immunoglobulin light chain (AL) amyloidosis. The mechanism of organ dysfunction resulting from amyloidosis has been a topic of debate. This review focuses on the ultrastructure of tissue damage resulting from amyloid deposition and therapeutic insights based on the pathophysiology of amyloidosis. Studies of nerve biopsy or cardiac autopsy specimens from patients with ATTR and AL amyloidoses show atrophy of cells near amyloid fibril aggregates. In addition to the stress or toxicity attributable to amyloid fibrils themselves, the toxicity of non-fibrillar states of amyloidogenic proteins, particularly oligomers, may also participate in the mechanisms of tissue damage. The obscuration of the basement and cytoplasmic membranes of cells near amyloid fibrils attributable to an affinity of components constituting these membranes to those of amyloid fibrils may also play an important role in tissue damage. Possible major therapeutic strategies based on pathophysiology of amyloidosis consist of the following: (1) reducing or preventing the production of causative proteins; (2) preventing the causative proteins from participating in the process of amyloid fibril formation; and/or (3) eliminating already-deposited amyloid fibrils. As the development of novel disease-modifying therapies such as short interfering RNA, antisense oligonucleotide, and monoclonal antibodies is remarkable, early diagnosis and appropriate selection of treatment is becoming more and more important for patients with amyloidosis.

Light Chain Amyloidosis (AL) Associated With B Cell Lymphoma a Single Center Experience

INTRODUCTION

Light chain (AL) amyloidosis and B-cell lymphoma represent 5% to 7% of all AL, Systemic amyloidosis, deposits in sites remote from the underlying lymphoma, and peritumoral amyloidosis deposition is within the immediate vicinity.

MATERIALS AND METHODS

We conducted a retrospectively study to identify and describe AL with B cell lymphoma at Princess Margaret Cancer Center from 01 January 1997 to 31 July 2019.

RESULTS

Thirty-five patients with AL and lymphoma, an incidence of 6, 2%, median age of diagnosis of 66 (range 47 to 86), majority male, most had underlying Waldestrom's Macroglobulinemia. 21 patients with peritumoral AL (PAL), and 15 with systemic AL. 42.8% of the patients had major organ involvement. 35% got treatment with Rituximab with alkylator, 20% received proteasome inhibitors, 17% patients were on a watch and wait approach, amyloid response showed very good partial response > 45.8%, and lymphoma ORR was 42.8%, with a median follow up of 31.5 months. A 36 month overall survival (OS) and progression-free survival (PFS) showed worse outcomes for heart involvement OS (P = .002), PFS (0.057) and IgM subtype OS (P = .02), PFS (0.01).

CONCLUSION

We have shown adverse outcome with IgM AL and to document a differences in OS and PFS not previously reported for PAL.

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.

Amyloidosis with Cardiac Involvement: Identification, Characterization, and Management

PURPOSE OF REVIEW

Amyloidosis is a protein deposition disease whereby a variety of precursor proteins form insoluble fibrils that deposit in tissues, causing organ dysfunction and, many times, death. Accurate characterization of the disease based on the nature of the precursor protein, organ involvement, and extent of disease is paramount to guide management. Cardiac amyloidosis is critical to understand because of its impact on prognosis and new treatment options available.

RECENT FINDINGS

New imaging methods have proven to be considerably valuable in the identification of cardiac amyloid infiltration. For treating clinicians, a diagnostic algorithm for patients with suspected amyloidosis with or without cardiomyopathy is shown to help classify disease and to direct appropriate genetic testing and management. For patients with light chain disease, recently introduced treatments adopted from multiple myeloma therapies have significantly extended progression-free and overall survival as well as organ response. In addition, new medical interventions are now available for those with transthyretin amyloidosis. Although cardiac amyloidosis contributes significantly to the morbidity and mortality associated with systemic disease, new tools are available to assist with diagnosis, prognosis, and management.

Future Perspectives

Opportunities and challenges in the field of systemic amyloidosis can be grouped into 4 categories. First, a deeper understanding of the pathogenesis of the disease is required. Second, a greater awareness of the disease, which will lead to an earlier diagnosis, is imperative. Third, end points for interventional trials are required to convey us to our fourth aspirations, which are novel therapies for patients with light chain amyloidosis.

MALDI mass spectrometry imaging unravels organ and amyloid-type specific peptide signatures in pulmonary and gastrointestinal amyloidosis

PURPOSE

Amyloidosis is a disease group caused by pathological aggregation and deposition of peptides in diverse tissue sites. Recently, matrix-assisted laser desorption/ionization mass spectrometry imaging coupled with ion mobility separation (MALDI-IMS MSI) was introduced as a novel tool to identify and classify amyloidosis using single sections from formalin-fixed and paraffin-embedded cardiac biopsies. Here, we tested the hypothesis that MALDI-IMS MSI can be applied to lung and gastrointestinal specimens.

EXPERIMENTAL DESIGN

Forty six lung and 65 gastrointestinal biopsy and resection specimens with different types of amyloid were subjected to MALDI-IMS MSI. Ninety three specimens included tissue areas without amyloid as internal negative controls. Nine cases without amyloid served as additional negative controls.

RESULTS

Utilizing a peptide filter method and 21 known amyloid specific tryptic peptides we confirmed the applicability of a universal peptide signature with a sensitivity of 100% and a specificity of 100% for the detection of amyloid deposits in the lung and gastrointestinal tract. Additionally, the frequencies of individual m/z-values of the 21 tryptic marker peptides showed organ- and tissue-type specific differences.

CONCLUSIONS AND CLINICAL RELEVANCE

MALDI-IMS MSI adds a valuable analytical approach to diagnose and classify amyloid and the detection frequency of individual tryptic peptides is organ-/tissue-type specific.

Kidney Biopsy in Patients With Monoclonal Gammopathy: A Multicenter Retrospective Cohort Study

Objectives: To analyze the clinical characteristics and renal pathological manifestations of patients with monoclonal gammopathy (MG) and kidney injury. Methods: This was a multicenter retrospective cohort study conducted at four tertiary hospitals in China. The study population comprised patients with MG admitted from January 1 2013 to December 31 2020. Hospitalization records, laboratory data, and kidney biopsy reports of all patients were collected from the electronic hospital information systems. The study outcomes included kidney disease progression and major hemorrhagic complications after kidney biopsy. Results: We identified 1,164 patients with MG, 782 (67.2%) of whom had underlying kidney injury. Of 101 patients who underwent kidney biopsy, 16 had malignant neoplasms. Amyloid nephropathy was the most common finding (n = 34, 33.7%), followed by membranous nephropathy (n = 18, 17.8%) and membranoproliferative nephritis (n = 8, 7.9%). Among 85 patients with non-malignant hematologic conditions who underwent kidney biopsy, 43 had MG of renal significance (MGRS) related lesions and 42 had MG-unrelated lesions. The risk of kidney disease progression was higher in patients with kidney injury than in patients without kidney injury. Conclusion: Among patients with MG and kidney injury, only 12.9% underwent kidney biopsy and more than 40% of these patients had MG-unrelated lesions. A kidney biopsy is safe and essential to maximize the possibility of correct diagnosis for patients with clinically suspected MG of renal significance (MGRS).

Advanced isolated light chain amyloid cardiomyopathy with negative immunofixation and normal free light chain ratio

Amyloid light chain (AL) cardiomyopathy is the most malignant specific cardiomyopathy. According to international recommendations, it should be ruled out non‐invasively using the serum free light chain (FLC) ratio and immunofixation electrophoresis in both serum and urine. Here, we report on a 69‐year‐old female patient with new‐onset heart failure with mid‐range ejection fraction. Cardiac imaging was highly suggestive of cardiac amyloidosis. Amyloid scintigraphy showed faint myocardial tracer uptake according to Perugini Score 1, but immunofixation was negative and the FLC ratio was normal, despite a slight increase in lambda FLCs. Endomyocardial biopsy revealed advanced myocardial lambda immunoglobulin light chain deposition. Clinically relevant extracardiac amyloid organ infiltration could not be detected. Conclusively, non‐invasive testing can in rare cases fail to exclude isolated AL amyloid cardiomyopathy. We suggest that even slight increases in serum lambda or kappa FLCs should be considered abnormal in suspected cardiac amyloidosis if non‐invasive testing delivers discrepant results.

First-line daratumumab shows high efficacy and tolerability even in advanced AL amyloidosis: the real-world experience

Background

Daratumumab was the first monoclonal CD38 antibody with single-agent activity approved for the treatment of multiple myeloma. Moreover, daratumumab demonstrated high response rates in relapsed immunoglobulin light-chain (AL) amyloidosis.

Patients and methods

In our single-center retrospective real-life case series, we analyzed the efficacy and safety of daratumumab as first-line treatment. Daratumumab was administered with low-dose dexamethasone alone or in combination with other multiple myeloma therapeutics

Results

Fourteen patients were eligible, including nine patients with cardiac stage IIIa or IIIb. Overall hematologic response rate was 100%, with 64.3% achieving complete response after a median of 16 cycles of treatment. Median time to hematologic response was 1.4 months. Organ response rates were 45.5% after a median of 4.0 months and 66.7% after a median of 10.0 months, for heart and kidney involvement, respectively. After a median follow-up of 20.5 months, two patients underwent successful autologous stem cell transplantation (ASCT), while another three patients were in preparation for ASCT. Three patients remained on daratumumab at the last follow-up. There were no unexpected toxicities and no grade III or IV adverse events, although more than half of our patients were in stage IIIa or IIIb.

Conclusion

Daratumumab proved to be highly effective in newly diagnosed AL amyloidosis with excellent hematologic and organ response rates, a remarkable safety profile, and good tolerability even in patients with advanced stage of disease.

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Daratumumab yields high hematologic response rates in untreated AL amyloidosis.

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Treatment is well tolerated even in advanced disease stages.

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No unexpected toxicity was observed.

Management of heart failure in cardiac amyloidosis using an ambulatory diuresis clinic

BACKGROUND

Recurrent congestion in cardiac amyloidosis (CA) remains a management challenge, often requiring high dose diuretics and frequent hospitalizations. Innovative outpatient strategies are needed to effectively manage heart failure (HF) in patients with CA. Ambulatory diuresis has not been well studied in restrictive cardiomyopathy. Therefore, we aimed to examine the outcomes of an ambulatory diuresis clinic in the management of congestion related to CA.

METHODS AND RESULTS

We retrospectively studied patients with CA seen in an outpatient HF disease management clinic for (1) safety outcomes of ambulatory intravenous (IV) diuresis and (2) health care utilization. Forty-four patients with CA were seen in the clinic a total of 203 times over 6 months. Oral diuretics were titrated at 96 (47%) visits. IV diuretics were administered at 56 (28%) visits to 17 patients. There were no episodes of severe acute kidney injury or symptomatic hypotension. There was a significant decrease in emergency department and inpatient visits and associated charges after index visit to the clinic. The proportion of days hospitalized per 1000 patient days of follow-up decreased as early as 30 days (147.3 vs 18.1/1000 patient days of follow-up, P< .001) and persisted through 180 days (33.6 vs 22.9/1000 patient days of follow-up, P< .001) pre- vs post-index visit to the clinic.

CONCLUSIONS

We demonstrate the feasibility of ambulatory IV diuresis in patients with CA. Our findings also suggest that use of a HF disease management clinic may reduce acute care utilization in patients with CA. Leveraging multidisciplinary outpatient HF clinics may be an effective alternative to hospitalization in patients with HF due to CA, a population who otherwise carries a poor prognosis and contributes to high health care burden.

Pharmacologic targeting of plasma cell endoplasmic reticulum proteostasis to reduce amyloidogenic light chain secretion

Light chain (LC) amyloidosis (AL) involves the toxic aggregation of amyloidogenic immunoglobulin LCs secreted from a clonal expansion of diseased plasma cells. Current AL treatments use chemotherapeutics to ablate the AL plasma cell population. However, no treatments are available that directly reduce the toxic LC aggregation involved in AL pathogenesis. An attractive strategy to reduce toxic LC aggregation in AL involves enhancing endoplasmic reticulum (ER) proteostasis in plasma cells to reduce the secretion and subsequent aggregation of amyloidogenic LCs. Here, we show that the ER proteostasis regulator compound 147 reduces secretion of an amyloidogenic LC as aggregation-prone monomers and dimers in AL patient-derived plasma cells. Compound 147 was established to promote ER proteostasis remodeling by activating the ATF6 unfolded protein response signaling pathway through a mechanism involving covalent modification of ER protein disulfide isomerases (PDIs). However, we show that 147-dependent reductions in amyloidogenic LCs are independent of ATF6 activation. Instead, 147 reduces amyloidogenic LC secretion through the selective, on-target covalent modification of ER proteostasis factors, including PDIs, revealing an alternative mechanism by which this compound can influence ER proteostasis of amyloidogenic proteins. Importantly, compound 147 does not interfere with AL plasma cell toxicity induced by bortezomib, a standard chemotherapeutic used to ablate the underlying diseased plasma cells in AL. This shows that pharmacologic targeting of ER proteostasis through selective covalent modification of ER proteostasis factors is a strategy that can be used in combination with chemotherapeutics to reduce the LC toxicity associated with AL pathogenesis.

Effects of Amyloid Light-Chain Amyloidosis on Clinical Characteristics and Prognosis in Multiple Myeloma: A Single-Center Retrospective Study

BACKGROUND

Amyloid light-chain amyloidosis (AL amyloidosis) is commonly associated with multiple myeloma. However, the clinical characteristics and prognosis of symptomatic and smoldering multiple myeloma with AL amyloidosis are not particularly clear.

METHODS

Patients with symptomatic and smoldering multiple myeloma in the Peking University First Hospital registry from 2010 to 2018 were studied. The clinical and laboratory information was collected from first presentation to death or until the last available clinical follow-up. The patients' survival and outcomes were analyzed, and the relationship between the clinical parameters and survival was also assessed.

RESULTS

Compared with symptomatic multiple myeloma patients without AL amyloidosis, patients with AL amyloidosis had higher incidence of BNP≧700pg/mL (P<0.001), ALP>187.5IU/L (P=0.032) and ALB<25g/L (P<0.001). Similarly, compared with smoldering multiple myeloma patients without AL amyloidosis, patients with AL amyloidosis had higher incidence of BNP≧700pg/mL (P=0.030) and Alb<25g/L (P=0.024). The existence of AL amyloidosis, especially those with the heart involvement, was related to shorter long-term survival of symptomatic and smoldering multiple myeloma according to univariate analyses. Renal involvement and gastrointestinal tract involvement had an impact on the prognosis of smoldering multiple myeloma but not on the symptomatic multiple myeloma. Cox regression model for overall survival detected BNP≧700pg/mL in symptomatic multiple myeloma having independent poorer prognostic significance (HR=2.455, P=0.004). Interestingly, BNP at diagnosis was significantly correlated with cardiac amyloidosis (r=0.496, P<0.001). Cox regression model for overall survival detected the presence of AL amyloidosis in smoldering multiple myeloma having independent poorer prognostic significance (HR=8.741, P=0.002).

CONCLUSION

AL amyloidosis is an independent poor prognostic factor for not only symptomatic multiple myeloma but also smoldering multiple myeloma. It is mainly because of involvement of important organs, especially the heart. AL amyloidosis probably has a greater impact on the prognosis of smoldering multiple myeloma than on the symptomatic multiple myeloma.

Neuromuscular amyloidosis: Unmasking the master of disguise

Amyloidosis refers to an etiologically heterogeneous group of protein misfolding diseases, pathologically characterized by extracellular amyloid fibrils producing congophillic amorphous deposits in organs and tissues, which may lead to severe organ dysfunction and mortality. Clinical presentations vary and are often nonspecific, depending on what organs or tissues are affected. In systemic amyloidosis, the peripheral nervous system is commonly affected, whereas the skeletal muscles are only rarely involved. Immunoglobulin light chain (AL) amyloidosis and hereditary transthyretin (ATTRv) amyloidosis are the most frequent types of systemic amyloidosis involving the neuromuscular system. Localized amyloidosis can occur in skeletal muscle, so-called isolated amyloid myopathy. Amyloid neuropathy typically involves small myelinated and unmyelinated sensory and autonomic nerve fibers early in the course of the disease, followed by large myelinated fiber sensory and motor deficits. The relentlessly progressive nature with motor, painful sensory and severe autonomic dysfunction, profound weight loss, and systemic features are distinct characteristics of amyloid neuropathy. Amyloid myopathy presentation differs between systemic amyloidosis and isolated amyloid myopathy. Long-standing symptoms, distal predominant myopathy, markedly elevated creatine kinase level, and lack of peripheral neuropathy or systemic features are highly suggestive of isolated amyloid myopathy. In ATTR and AL amyloidosis, early treatment correlates with favorable outcomes. Therefore, awareness of these disorders and active screening for amyloidosis in patients with neuropathy or myopathy are crucial in detecting these patients in the everyday practice of neuromuscular medicine. Herein, we review the clinical manifestations of neuromuscular amyloidosis and provide a diagnostic approach to this disorder.

Bortezomib-Based Induction Is Associated with Superior Outcomes in Light Chain Amyloidosis Patients Treated with Autologous Hematopoietic Cell Transplantation Regardless of Plasma Cell Burden

The benefits of pre-transplant induction chemotherapy in light chain (AL) amyloidosis, a low burden plasma cell (PC) neoplasm associated with multiorgan dysfunction, is debatable, although with the availability of bortezomib, this approach is being increasingly pursued. We analyzed the outcomes of AL amyloidosis patients undergoing autologous hematopoietic cell transplant between 2014 and 2018 that were reported to the Center for International Blood and Marrow Transplant Research database. Of 440 patients, 294 received bortezomib-based induction, and 146 received no induction. Patients receiving induction had greater PC burden compared to no induction (PC 10% or more, 39% versus 11%; P < .01). At 2 years, the induction group compared to no induction had lower relapse/progression: 13% (9% to 18%) versus 23% (16% to 32%) (P = .02); better progression-free survival (PFS): 82% (77% to 87%) versus 69% (61% to 77%) (P < .01); and similar overall survival (OS): 92% (88% to 95%) versus 89% (84% to 94%) (P = .22), findings that were confirmed on multivariate analysis. A subset analysis limited to patients with <10% PC also showed superior relapse/progression (hazard ratio [HR], .43; 95% confidence interval [CI], .24 to .78; P < .01) and PFS (HR, .43; 95% CI, .26 to .72; P < .01) for induction compared to no induction. Thus, we conclude that pre-transplant bortezomib-based induction was associated with improved relapse/progression and PFS in AL amyloidosis. Longer survival follow-up is warranted, as OS was excellent in both cohorts at 2 years.

Daratumumab for relapsed AL amyloidosis-When cumulative real-world data precedes clinical trials: A multisite study and systematic literature review

OBJECTIVES

Patients with relapsed/refractory AL amyloidosis (RRAL) have poor prognosis, but emerging data shows promising results with the use daratumumab. We evaluated daratumumab treatment in RRAL in real-world setting.

METHODS

A retrospective multisite study of RRAL patients treated with daratumumab alone and in combinations.

RESULTS

Forty-nine patients, diagnosed between 1.1.2008 and 1.2.2018 were included; 27% also had multiple myeloma (MM). Revised Mayo score was ≥ 3 in 67%. Hematologic overall response rate was 81%, 64% achieved very good partial response (VGPR) or better. Concurrent active MM was associated with lower rates of VGPR (OR 0.19, 95% CI 0.04-0.81; P = .03) in a multi-variate analysis. Cardiac and renal responses were 74% and 73%, respectively. Median progression-free survival (PFS) was 28.4 months and median overall survival (OS) was not reached; 2-year PFS and OS were 68.6 ± 7.5% and 90.4 ± 4.6%, respectively. Hematologic response correlated with prolonged PFS and OS. Daratumumab was safe and well tolerated, no patients discontinued therapy due to toxicity. Our data was aligned with outcomes from a systematic literature review, which identified 10 case series (n = 517) and 2 clinical trials (n = 62) meeting prespecified criteria.

CONCLUSIONS

Our data support favorable safety tolerability and efficacy of daratumumab among non-selective RRAL patients in a real-world setting.

Emerging drugs for the treatment of light chain amyloidosis

INTRODUCTION

Systemic AL amyloidosis is a protein-misfolding disorder that is characterized by the deposition of insoluble amyloid fibrils derived from kinetically unstable light chains. Achieving a rapid and deep hematologic response is critical for long-term survival.

AREAS COVERED

This review covers the existing and emerging treatment options for systemic AL, divided into anti-plasma cell and fibril-directed therapies. The anti-CD38 monoclonal antibody daratumumab has demonstrated an unprecedented hematologic response rate and will become the new standard-of-care in newly diagnosed patients in combination with CyBorD/VCD. Other plasma cell-directed drugs that have prospective data on safety and efficacy in AL include proteasome inhibitors [bortezomib and ixazomib], immunomodulatory drugs [lenalidomide and pomalidomide], and alkylating agents [melphalan and bendamustine]. A major unmet need is the development of fibril-directed therapies with the goal of eliminating amyloid fibrils that are already deposited in vital organs.

EXPERT OPINION

The treatment of newly diagnosed AL in the future will likely include daratumumab-based therapy in conjunction with fibril-directed therapy. The most promising second line drugs are venetoclax [for t(11;14)] and pomalidomide, with several others in the pipeline, including antibody-drug conjugates. Minimal residual disease will emerge as a new endpoint for drug development and will potentially guide treatment duration.