Novel monoclonal antibodies: A really specific therapy for light chain amyloidosis

Light chain amyloidosis is a rare disease caused by clonal plasma cells in the bone marrow generating an excessive amount of immunoglobulin light chains. These chains misfold and produce insoluble fibrils that deposit in various organs, including the heart, kidneys, liver, nervous system, and digestive tract. Life expectancy and symptoms during the course of the disease vary depending on which and how many organs are affected. Targeted plasma cell therapy has significantly advanced the clinical management of amyloidosis, with ongoing progress. However, current clinical studies are investigating innovative targets, drug combinations and treatment strategies to improve therapeutic outcomes by minimizing adverse effects and refining patient prognosis in these challenging hematological conditions. In this paper, we review the state of the art regarding the use of anti-amyloid antibodies, as a revolutionary and innovative approach in the current scenario of amyloid treatment.

Transgenic amyloid precursor protein mouse models of amyloidosis. Incomplete models for Alzheimer's disease but effective predictors of anti-amyloid therapies

INTRODUCTION

Amyloid precursor protein (APP) transgenic mice are models of Alzheimer's disease (AD) amyloidosis, not all of AD. Diffuse, compacted, and vascular deposits in APP mice mimic those found in AD cases.

METHODS

Most interventional studies in APP mice start treatment early in the process of amyloid deposition, consistent with a prevention treatment regimen. Most clinical trials treat patients with established amyloid deposits in a therapeutic treatment regimen.

RESULTS

The first treatment to reduce amyloid and cognitive impairment in mice was immunotherapy. The APP mouse models not only predicted efficacy, but presaged the vascular leakage called ARIA. The recent immunotherapy clinical trials that removed amyloid and slowed cognitive decline confirms the utility of these early APP models when used in therapeutic designs.

DISCUSSION

New mouse models of AD pathologies will add to the research armamentarium, but the early models have accurately predicted responses to amyloid therapies in humans.

Immunoglobulin light chain amyloidosis: 2024 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include heart failure with preserved ejection fraction, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical smoldering multiple myeloma or MGUS."

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for the diagnosis of AL amyloidosis. Organ biopsy is not required in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP or BNP), serum troponin T(or I), and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four stages; 5-year survivals are 82%, 62%, 34%, and 20%, respectively.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Current first-line therapy with the best outcome is daratumumab, bortezomib, cyclophosphamide, and dexamethasone. The goal of therapy is a ≥VGPR. In patients failing to achieve this depth of response options for consolidation include pomalidomide, stem cell transplantation, venetoclax, and bendamustine.

FUTURE CHALLENGES

Delayed diagnosis remains a major obstacle to initiating effective therapy prior to the development of end-stage organ failure. Trials of antibodies to deplete deposited fibrils are underway.

Re-Engineering Therapeutic Anti-Aβ Monoclonal Antibody to Target Amyloid Light Chain

Amyloidosis involves the deposition of misfolded proteins. Even though it is caused by different pathogenic mechanisms, in aggregate, it shares similar features. Here, we tested and confirmed a hypothesis that an amyloid antibody can be engineered by a few mutations to target a different species. Amyloid light chain (AL) and β-amyloid peptide (Aβ) are two therapeutic targets that are implicated in amyloid light chain amyloidosis and Alzheimer's disease, respectively. Though crenezumab, an anti-Aβ antibody, is currently unsuccessful, we chose it as a model to computationally design and prepare crenezumab variants, aiming to discover a novel antibody with high affinity to AL fibrils and to establish a technology platform for repurposing amyloid monoclonal antibodies. We successfully re-engineered crenezumab to bind both Aβ42 oligomers and AL fibrils with high binding affinities. It is capable of reversing Aβ42-oligomers-induced cytotoxicity, decreasing the formation of AL fibrils, and alleviating AL-fibrils-induced cytotoxicity in vitro. Our research demonstrated that an amyloid antibody could be engineered by a few mutations to bind new amyloid sequences, providing an efficient way to reposition a therapeutic antibody to target different amyloid diseases.

Feasibility and safety of left bundle branch area pacing in cardiac amyloidosis. A single center experience

BACKGROUND

Conventional right ventricle (RV) pacemaker stimulation has been associated with worse clinical outcomes in patients with cardiac amyloidosis (CA). Left bundle branch area pacing (LABPP) has been suggested as a promising alternative. We sought to assess the safety, feasibility, and outcomes of LABPP in patients with CA.

METHODS

We retrospectively analyzed echocardiography and pacing parameters and clinical outcomes in 23 consecutive patients with CA and LBBAP implanted from June 2020 to October 2022.

RESULTS

LBBAP was successfully performed in 22 over 23 patients (19 male, 78.6 ± 11.7 years, 20 ATTR, mean LVEF 45.5 ± 16.2%). After the procedure, 9 patients showed Qr pattern and 11 a qR pattern in V1 on ECG. Average procedure time was 67 ± 28 min. After 7.7 ± 5.2 months follow-up, no procedure-related complications had occurred. Although, a significant reduction in QRS width (p = .001) was achieved, we did not observe significant changes in LVEF and Nt ProBNP at 6 months of follow-up. Pacing parameters were stable during follow-up: LBB capture threshold and R wave amplitude were 1.0 ±  0.5 V and 10.6 ± 6.0 mV versus 0.8 ±  0.1 V, p = .21 and 10.6 ± 5.1 mV (p = .985) at follow up.

CONCLUSION

LBBAP is safe and feasible pacing technique for patients with CA. LBBAP is associated with significant narrowing of QRSd without worsening in LVEF and Nt-proBNP.

Cardiac Amyloidosis: Clinical Features, Pathogenesis, Diagnosis, and Treatment

Cardiac amyloidosis is a type of amyloidosis that deserves special attention as organ involvement significantly worsens the prognosis. Cardiac amyloidosis can be grouped under three main headings: immunoglobulin light chain (AL) amyloidosis that is dependent on amyloidogenic monoclonal light chain production; hereditary Transthyretin (TTR) amyloidosis that results from accumulation of mutated TTR; and wild-type (non-hereditary) TTR amyloidosis formerly known as senile amyloidosis. Although all three types cause morbidity and mortality due to severe heart failure when untreated, they contain differences in their pathogenesis, clinical findings, and treatment. In this article, the clinical features, pathogenesis, diagnosis, and treatment methods of cardiac amyloidosis will be explained with an overview, and an awareness will be raised in the diagnosis of this disease.

Renal AA amyloidosis revealing extramedullary plasmocytoma

Introduction

Solitary plasmacytoma is a rare, localized malignancy. Bone localizations are the most common. Extramedullary plasmacytomas are much rarer. They are most often in the upper respiratory tract and can be complicated by amyloidosis. Here is an original report of a mediastinal extramedullary plasmacytoma revealed by type AA renal amyloidosis.

Case presentation

We present the case of a 52-year-old patient with mediastinal extramedullary plasmocytoma diagnosed by renal failure due to type AA renal amyloidosis. Treatment was based on surgery with chemotherapy based on prednisone and melphalan. The patient presented end-stage renal failure that required hemodialysis at discharge.

Conclusion

Extramedullary plasmacytoma is a rare tumour that may be associated with amyloidosis, usually type AL. To our knowledge, its association with AA amyloidosis has not been reported in the literature. Treatment is based on surgery combined with radiotherapy or chemotherapy.

Recent Progress in the Development and Clinical Application of New Drugs for Transthyretin Cardiac Amyloidosis

ABSTRACT

Transthyretincardiac amyloidosis is a rare disease that has gained significant attention in recent years because of misfolding of transthyretin fibrils produced by the liver, leading to their deposition in the myocardium. The disease has an insidious onset, nonspecific clinical manifestations, and historically lacked effective drugs, making early diagnosis and treatment challenging. The survival time of patients largely depends on the extent of heart involvement at the time of diagnosis, and conventional treatments for cardiovascular disease do not provide significant benefits. Effective management of the disease requires treatment of its underlying cause. Orthotopic liver transplantation and combined hepato-heart transplantation have been clinically effective means of treating transthyretin cardiac amyloidosis mutants for many years. However, transplantation has many limitations in clinical practice. In recent years, the development of new drugs has brought new hope to patients. This review presents the latest advances in drug development and clinical application to provide a reference for clinicians managing transthyretin cardiac amyloidosis.

Pathway for the Diagnosis and Management of Cardiac Amyloidosis

The systemic amyloidoses are a broad spectrum of diseases that result from misfolding of proteins that aggregate into amyloid fibrils. In cardiac amyloidosis, amyloid fibrils accumulate in the interstitial space between cardiac myocytes causing cellular injury and impairing compliance. Current data suggest that cardiac amyloidosis is more common than previously thought. Advances in cardiac imaging, diagnostic strategies, and therapies have improved the recognition and treatment of cardiac amyloidosis. A position statement for the diagnosis and treatment of cardiac amyloidosis has been published in 2021 by the European Society of Cardiology and an expert consensus decision pathway was published in 2023 by the American College of Cardiology. These are excellent documents but quite lengthy and complex. For this reason, our team developed a novel and simple pathway to help health care providers diagnose and treat patients with cardiac amyloidosis. Our pathway starts with a section titled "suspicion" in which we provide simple clues or "red flags" that are associated with the cardiac amyloidosis phenotype. It is followed by a section titled "diagnosis," where we present in a simplified 2 × 2 format the laboratory and imaging tests that must be performed for an accurate diagnosis. In the section titled "treatment," we describe the 4 pillars in the management of patients with cardiac amyloidosis, which includes the following: heart failure treatments, management of arrhythmias, treatment of significant aortic stenosis, and appropriate selection of disease modifying therapies. Our algorithm ends with our simplified recommendation for follow-up.

Standardising Care and Treatment of Transthyretin Amyloid Cardiomyopathy

Transthyretin cardiac amyloidosis (ATTR-CA) has been traditionally considered a rare and inexorably fatal condition. ATTR-CA now is an increasingly recognised cause of heart failure and mortality worldwide with effective pharmacological treatments. Advances in non-invasive diagnosis, coupled with the development of effective treatments, have transformed the diagnosis of ATTR-CA, which is now possible without recourse to endomyocardial biopsy in around 70% of cases. Many patients are now diagnosed at an earlier stage. Echocardiography and cardiac magnetic resonance have enabled identification of patients with possible ATTR-CA and more accurate prognostic stratification. Therapies able to slow or halt ATTR-CA progression and increase survival are now available and there is also evidence that patients may benefit from specific conventional heart failure medications. A wide horizon of possibilities is unfolding and awaits discovery.

Safety and Efficacy of Propylene Glycol-Free Melphalan in Patients with AL Amyloidosis Undergoing Autologous Stem Cell Transplantation: Results of a Phase II Study

Patients with systemic light chain (AL) amyloidosis undergoing treatment with high-dose melphalan and autologous stem cell transplantation (HDM/SCT) may develop renal and cardiac toxicities potentially exacerbated by the co-solvent propylene glycol in conventional melphalan formulations. We investigated the safety and efficacy of propylene glycol-free melphalan (PGF-Mel) during HDM/SCT in patients with AL amyloidosis (ClinicalTrials.gov identifier NCT02994784). The primary objective of this phase II, open-label study was evaluation for renal dysfunction, new cardiac arrhythmias, and postural hypotension related to autonomic dysfunction. Secondary objectives included time to neutrophil and platelet engraftment, treatment-related mortality (TRM), overall hematologic response, organ response, and number of peritransplantation hospitalizations. Twenty-eight patients with AL amyloidosis enrolled, of whom 27 underwent HDM/SCT. PGF-Mel at 140 to 200 mg/m2 was administered i.v. in 2 equally divided doses. Patients were monitored for up to 30 days after the last administration of PGF-Mel to assess for treatment-related toxicity. Patients were followed for 12 months from the time of treatment with HDM/SCT for evaluation of hematologic and organ responses. Kaplan-Meier analysis was used to estimate progression-free survival. Two patients (7%) developed renal dysfunction, 5 (19%) experienced new cardiac arrhythmias, and 3 (11%) developed orthostatic hypotension. All patients achieved neutrophil and platelet engraftment, at a median of 10 days and 17 days post-HDM/SCT, respectively. TRM on day +100 was 0%. Peritransplantation hospitalization was required for 23 patients (85%). The most common nonhematologic adverse events were diarrhea (93%), fatigue (82%), and nausea (74%). At 6 months post-HDM/SCT, hematologic complete response or very good partial response occurred in 66% of the patients. At 12 months post-HDM/SCT, renal response occurred in 12 of 23 (52%) patients with renal involvement, and cardiac response occurred in 3 of 11 (27%) patients with evaluable cardiac involvement. Our data indicate that PGF-Mel is safe and efficacious as a high-dose conditioning regimen for autologous SCT in patients with AL amyloidosis.

Cardiac and renal AL amyloidosis controlled by autologous stem cell transplantation for 17 years accompanying late onset atrial fibrillation and complete atrioventricular block

Amyloid light chain (AL) amyloidosis is a rare hematologic disease that may involve multiple organs. Amongst the organs, cardiac involvement causes the greatest concern as its treatment is challenging. Diastolic dysfunction rapidly progresses to decompensated heart failure, pulseless electrical activity, and atrial standstill due to electro-mechanical dissociation resulting in death. High-dose melphalan plus autologous stem cell transplantation (HDM-ASCT) is the most radical treatment but its risk is very high and thus only less than 20% of patients can receive this therapy under criteria that can suppress treatment-related mortality. In substantial proportion of patients, levels of M protein remain elevated, and organ response cannot be achieved. Moreover, relapse may occur, making prediction of treatment response and judgement of disease eradication very difficult. Herein we report a case of AL amyloidosis who was treated with HDM-ASCT, resulting in preserved cardiac function and resolution of proteinuria for more than 17 years after HDM-ASCT ensuing atrial fibrillation and complete atrioventricular block required management by catheter ablation and pacemaker implantation 10 years and 12 years after transplantation, respectively.

Peripheral Nervous, Hepatic, and Gastrointestinal Endpoints for AL Amyloidosis Clinical Trials: Report from the Amyloidosis Forum Multi-organ System Working Group

Systemic immunoglobulin light chain (AL) amyloidosis is a heterogeneous rare disease driven by a destructive monoclonal gammopathy and typified by misfolded immunoglobulin light and/or heavy chains which aggregate and deposit in organs as insoluble amyloid fibrils. Disease heterogeneity is driven by the degree of multi-systemic involvement; cardiac, renal, neurological, and gastrointestinal (GI) systems are affected to varying degrees in different patients. While prognosis is primarily driven by hematologic response to treatment and outcomes associated with cardiac events and overall survival, the involvement of the peripheral nervous, hepatic, and GI systems can also have a significant impact on patients. The Amyloidosis Forum ( https://amyloidosisforum.org ) is a public-private partnership between the nonprofit Amyloidosis Research Consortium ( www.arci.org ) and the US Food and Drug Administration (FDA) Center for Drug Evaluation and Research formed to advance drug development for the treatment of systemic amyloid disorders. A series of virtual workshops focused on the development of novel, patient-relevant endpoint components and analytical strategies for clinical trials in AL amyloidosis. This review summarizes the proceedings and recommendations of the Multi-Systemic Working Group which identified, reviewed, and prioritized endpoints relevant to the impacts of AL amyloidosis on the peripheral nervous, hepatic, and GI systems. The Working Group comprised amyloidosis experts, patient representatives, statisticians, and representatives from the FDA, Medicines and Healthcare products Regulatory Agency (MHRA), and pharmaceutical companies. Prioritized neuropathy/autonomic endpoints included a modified form of the Neuropathy Impairment Score (NIS + 7) and the Composite Autonomic Symptom Score (COMPASS-31), respectively. Alkaline phosphatase was identified as the most relevant indicator of liver involvement and disease progression. Following extensive review of potential GI endpoints, the Working Group identified multiple exploratory endpoints. These recommended components will be further explored through evaluation of clinical trial datasets and possible integration into composite endpoint analysis.

Bradyarrhythmias in Cardiac Amyloidosis and Role of Pacemaker

Cardiac amyloidosis (CA) is an underdiagnosed disease that is caused by deposition of misfolded transthyretin (ATTR) or immunoglobulin light chain (AL) fibrils in the myocardium. Bradyarrhythmias are commonly seen in CA, due to disruption of conducting system by amyloid fibrils. Atrioventricular conduction defect is more common than sinus node dysfunction. Bradyarrhythmias are most prevalent in wtATTR, followed by hATTR and AL. Pacemaker implantation, when indicated, can help provide symptomatic relief but does not confer mortality benefit. Progression of conduction system disease is common and often leads to increased right ventricular pacing burden with time. Therefore, cardiac resynchronizing therapy (biventricular therapy) is often considered as a better and safer option in these patients. Finally, the role of prophylactic pacemaker implantation is controversial, and current guidelines do not recommend prophylactic pacemaker insertion in CA patients.

Epidemiology and clinical outcomes of light-chain amyloidosis in Sweden: A nationwide population-based study

OBJECTIVES

This study evaluated data from six Swedish national registries to fill current evidence gaps on the epidemiology, clinical burden, and overall survival (OS) associated with light-chain (AL) amyloidosis.

METHODS

Patients newly diagnosed with AL amyloidosis were identified using six linked Swedish nationwide population-based registers. For each case, individuals from the general population were selected and matched with a maximum ratio of 1:5 based on age, sex, calendar year, and county.

RESULTS

846 patients newly diagnosed with AL amyloidosis and 4227 demographically matched individuals were identified. From 2011 to 2019, annual AL amyloidosis incidence increased from 10.5 to 15.1 cases per million. At baseline, patients with AL amyloidosis had a significantly higher disease burden including higher rates of cardiac and renal failure relative to the comparison group. Among patients with AL amyloidosis, 21.5% had incident heart failure and 17.1% had incident renal failure after initial diagnosis. Median OS for patients with AL amyloidosis was 56 months versus not reached in the matched general population comparison group.

CONCLUSION

The incidence of newly diagnosed AL amyloidosis in Sweden increased over time with AL amyloidosis being associated with a higher risk of cardiac/renal failure and all-cause mortality compared with the general population.

The spectrum of pulmonary amyloidosis

Amyloidosis is a disease caused by misfolded proteins that deposit in the extracellular matrix as fibrils, resulting in the dysfunction of the involved organ. The lung is a common target of Amyloidosis, but pulmonary amyloidosis is uncommonly diagnosed since it is rarely symptomatic. Diagnosis of pulmonary amyloidosis is usually made in the setting of systemic amyloidosis, however in cases of localized pulmonary disease, surgical or transbronchial tissue biopsy might be indicated. Pulmonary amyloidosis can be present in a variety of discrete entities. Diffuse Alveolar septal amyloidosis is the most common type and is usually associated with systemic AL amyloidosis. Depending on the degree of the interstitial involvement, it may affect alveolar gas exchange and cause respiratory symptoms. Localized pulmonary Amyloidosis can present as Nodular, Cystic or Tracheobronchial Amyloidosis which may cause symptoms of airway obstruction and large airway stenosis. Pleural effusions, mediastinal lymphadenopathy and pulmonary hypertension has also been reported. Treatment of all types of pulmonary amyloidosis depends on the type of precursor protein, organ involvement and distribution of the disease. Most of the cases are asymptomatic and require only close monitoring. Diffuse alveolar septal amyloidosis treatment follows the treatment of underlying systemic amyloidosis. Tracheobronchial amyloidosis is usually treated with bronchoscopic interventions including debulking and stenting or with external beam radiation. Long-term prognosis of pulmonary amyloidosis usually depends on the type of lung involvement and other organ function.

How I Approach Light Chain Amyloidosis

Immunoglobulin Light Chain Amyloidosis (AL) is a progressive disease which leads to organ dysfunction and death. Tremendous progress has been made in staging, response, and treatment. The key to better survival though is early diagnosis which can be difficult since the symptoms are often nonspecific and can be seen in more common conditions. Once the diagnosis is confirmed, staging systems are available to provide prognosis on overall and renal survival. There are a number of treatments now available that are effective and well-tolerated. Response criteria have also been developed for hematologic and renal response in order to maximize response and minimize adverse effects. Newer therapies are being developed in particular anti-fibril therapies that are in clinical trials. For those patients who had a very good partial response or better, kidney transplantation may be an option if the kidney failure is not reversed.

A Rare Case of Subcutaneous Amyloidoma Associated with Localized Lymphoplasmacytic Lymphoma: Diagnostic Challenges and Treatment Considerations

BACKGROUND AL amyloidomas are solitary, localized, tumor-like deposits of immunoglobulin light-chain-derived amyloid fibrils in the absence of systemic amyloidosis. A rare entity, they have been described in various anatomical sites, typically in spatial association with a sparse lymphoplasmacytic infiltrate, ultimately corresponding to a clonal, malignant, lymphomatous disorder accounting for the amyloidogenic activity. Most frequently, the amyloidoma-associated hematological disorder corresponds to either a solitary plasmacytoma or an extranodal marginal zone lymphoma of MALT. Much rarer is the association with lymphoplasmacytic lymphoma, which by itself is usually a bone marrow-bound disorder with systemic burden. The almost anecdotic combination of an amyloidoma and a localized lymphoplasmacytic lymphoma deserves attention, as it entails a thorough diagnostic workup to exclude systemic involvement and a proportionate therapeutic approach to avoid overtreatment. A review of the literature provides an insight on pathogenesis and prognosis, and can assist both pathologists and clinicians in establishing optimal patient management strategies. CASE REPORT We herein report the incidental finding of a subcutaneous amyloidoma caused by a spatially related, similarly localized lymphoplasmacytic lymphoma diagnosed in a 54-year-old female patient with no other disease localizations and a complete remission following 2 subsequent surgical excisions. CONCLUSIONS Whatever the specific combination of an amyloidoma and the related hematological neoplasm, a multidisciplinary collaboration and a comprehensive clinical-pathological staging are warranted to exclude systemic involvement and identify patients with localized diseases who would benefit from local active treatment and close follow-up.

A retrospective analysis of clinical features and treatment outcome in 21 patients with immunoglobulin M-related light-chain amyloidosis in Japan: a study from the Amyloidosis Research Committee

We retrospectively gathered data of 21 patients (13 male and 8 female; median age 65 years) diagnosed with immunoglobulin M (IgM)-related light-chain (AL) amyloidosis in Japan to investigate characteristics of IgM-AL amyloidosis and its optimal treatment strategy. Median IgM and difference free light chain (FLC) at diagnosis were 1257 mg/dl and 34.3 mg/l, respectively. Organ involvement was observed in the heart in 7 patients (33%), kidneys in 15 (71%), and lymph nodes in 5 (24%). Initial treatments were melphalan/dexamethasone in 7 patients, bortezomib/cyclophosphamide/dexamethasone in 3, autologous stem cell transplantation in 3, rituximab/bendamustine in 1, other in 3, and none in 4. Hematological responses among 15 evaluable patients were as follows: 3 reached complete response (CR), 4 partial response (PR), and 1 very good PR (VGPR), making the overall response rate of PR or better 40%. Median overall survival (OS) was 14.0 months and 1-year OS was 71.4%. Prognosis was significantly poorer in patients with cardiac involvement than those with non-cardiac involvement (1-year OS 27.8% vs. 85.7%, p = 0.0468). The involved FLC value was low in several patients and therapeutic response was difficult to assess. Further study is necessary to determine the optimal treatment for IgM-AL amyloidosis.

Recent successes in heart failure treatment

Remarkable recent advances have revolutionized the field of heart failure. Survival has improved among individuals with heart failure and a reduced ejection fraction and for the first time, new therapies have been shown to improve outcomes across the entire ejection fraction spectrum of heart failure. Great strides have been taken in the treatment of specific cardiomyopathies such as cardiac amyloidosis and hypertrophic cardiomyopathy, whereby conditions once considered incurable can now be effectively managed with novel genetic and molecular approaches. Yet there remain substantial residual unmet needs in heart failure. The translation of successful clinical trials to improved patient outcomes is limited by large gaps in implementation of care, widespread lack of disease awareness and poor understanding of the socioeconomic determinants of outcomes and how to address disparities. Ongoing clinical trials, advances in phenotype segmentation for precision medicine and the rise in technology solutions all offer hope for the future.

A review of transthyretin cardiac amyloidosis

Transthyretin cardiac amyloidosis is a progressive disease known to cause heart failure, conduction anomalies, and arrythmias. Due to poor outcomes and mortality from severe cardiomyopathy, prevalence and incident rates are often underreported. As global longevity is increasing and rates of amyloidosis are also increasing, there is a need to improve diagnostic and therapeutic interventions. Previously, symptom management and transplantation were the mainstay of treatment for heart failure symptoms, but studies using RNAi and siRNA technologies have shifted the paradigm of therapeutic strategy in amyloid cardiomyopathy management. Additionally, early detection and clinical monitoring with numerous imaging and non-imaging techniques are being increasingly investigated. Here, we review the epidemiology, pathophysiology, diagnosis, and management of transthyretin amyloid cardiomyopathy.

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Amyloidosis is a severe disease caused by protein misfolding and deposition in tissues and organs. Thirty-eight different proteins are known to be amyloidogenic. Amyloidosis is categorized into inherited or acquired, and systemic or localized. Light-chain (AL)- and transthyretin (ATTR) amyloidosis are the two most common subtypes. Awareness, early diagnosis, accurate subtyping and relevant treatment are crucial for the management. Novel therapies of systemic AL and ATTR amyloidosis have considerably improved outcome and survival. The aim of this review is to increase awareness and knowledge on diagnosing amyloidosis.

Cardiac and autologous stem cell transplantation hematopoietic in patients with AL amyloidosis

OBJECTIVE

To describe the evolution of serum free light chains (FLC) in the period between orthotopic heart transplantation (OHT) and autologous stem cell transplantation (ASCT), the hematological response one year after ASCT and chemotherapy and immunosuppressive treatment in patients with AL amyloidosis.

METHOD

Case series of consecutive patients diagnosed with AL amyloidosis who received OHT followed by ASCT from the Institutional Registry of Amyloidosis of the Italian Hospital of Buenos Aires, between January 2010 and November 2021. FLC values between transplants and at year post ASCT. Quantitative variables were described with their median and interquartile range. Categorical variables as absolute and relative frequencies.

RESULTS

Of 106 patients with AL amyloidosis, 6 had an OHT followed by ASCT. The median age was 55 years. Most were men (n = 5). In the period between transplants, the involved CLL decreased in two patients and remained stable in three. All achieved complete hematologic remission 1 year after ASCT. A single patient presented relapse in the transplanted solid organ. Tacrolimus, mycophenolate mofetil, and corticosteroids were the immunosuppressive regimen used after OHT.

CONCLUSIONS

OHT represents a treatment option in patients with severe heart failure due to amyloidosis, allowing later intensive treatment with induction chemotherapy and ASCT. Although studies are lacking, immunosuppressive therapy after OHT might have some effect on clonal plasma cells.

Bad players in AL amyloidosis in the current era of treatment

INTRODUCTION

Systemic AL amyloidosis (ALA) is a clonal plasma cell (PC) disease characterized by deposition of amyloid fibrils in different organs and tissues. Traditionally, the prognosis of ALA is poor and is primarily defined by cardiac involvement. The modern prognostic models are based on cardiac markers and free light chain difference (dFLC). Cardiac biomarkers have low specificity and are dependent on renal function, volume status, and cardiac diseases other than ALA. New therapies significantly improved the prognosis of the disease. The advancements in technologies - cardiac echocardiography (ECHO) and cardiac MRI (CMR), as well as new biological markers, relying on cardiac injury, inflammation, endothelial damage, and clonal and non-clonal PC markers are promising.

AREAS COVERED

An update on the prognostic significance of cardiac ALA, number of involved organs, response to treatment, including minimal residual disease (MRD), ECHO, MRI, and new biological markers will be discussed. The literature search was done in PubMed and Google Scholar, and the most recent and relevant data are included.

EXPERT OPINION

Prospective multicenter trials, evaluating multiple clinical and laboratory parameters, should be done to improve the risk assessment models in ALA in the modern era of therapy.

The importance of pathways to facilitate early diagnosis and treatment of patients with cardiac amyloidosis

Cardiac amyloidosis (CA) is a condition caused by extracellular deposition of amyloid fibrils in the heart. It is an underdiagnosed disease entity which can present with a variety of cardiac and non-cardiac manifestations. Diagnosis usually follows an initial suspicion based on clinical evaluation or imaging findings before confirmation with subsequent imaging (echocardiography, cardiac magnetic resonance imaging, 3,3-diphosphono-1,2-propanodicarboxylic acid scintigraphy) in combination with biochemical screening for monoclonal dyscrasia (serum free light chains and serum and urine electrophoresis) and/or histology (bone marrow trephine, fat or endomyocardial biopsy). More than 95% of CA can be classified as either amyloid light-chain (AL) CA or amyloid transthyretin (ATTR) CA; these two conditions have very different management strategies. AL-CA, which may be associated with multiple myeloma, can be managed with chemotherapy agents, autologous stem cell transplantation, cardiac transplant and supportive therapies. For ATTR-CA, there is increasing importance in making an early diagnosis because of novel treatments in development, which have transformed this once incurable disease to a potentially treatable disease. Timely diagnosis is crucial as there may only be a small window of opportunity where patients can benefit from treatment beyond which therapies may be less effective. Reviewing the existing patient pathway provides a basis to better understand the complexities of real-world activities which may be important to help reduce missed opportunities related to diagnosis and treatment for patients with CA. With healthcare provider interest in improving the care of patients with CA, the development of an optimal care pathway for the condition may help reduce delays in diagnosis and treatment and thus enhance patient outcomes.

A comprehensive overview of AL amyloidosis disease characteristics accumulated over two decades at a single referral center in Korea

BACKGROUND

Characteristics of AL amyloidosis across Asia are not well-described in the literature. Thus, we overviewed the incidence and disease characteristics of AL amyloidosis in Korea.

METHODS

We collected medical records of 302 AL amyloidosis patients and compared survival outcomes by predominant treatment strategy and at four time points: 1995-2003, 2004-2008, 2009-2013, and 2014-2018.

RESULTS

The median age was 62 years (36-83). One hundred forty-one patients were classified as stage III (26.3%) or IV (47.9%). The patients diagnosed between 2014 and 2018 survived longer than those diagnosed at other time points due to the introduction of bortezomib (p < 0.01). In addition, patients who received upfront ASCT survived longer than those who received salvage ASCT or chemotherapy alone (p < 0.01). However, most of the 85 patients who experienced early death within 6 months were older than 75 years, had BMI less than 20, and had a high disease burden.

CONCLUSIONS

The incidence of AL amyloid has increased and survival outcomes have improved gradually, most likely due to introduction of novel agents and upfront ASCT. However, not all patients are suitable for these potent treatment modalities, and avoiding early death within 6 months remains a challenge.

Treatment patterns and outcomes in light chain amyloidosis: An institutional registry of amyloidosis report in Argentina

Light chain (AL) amyloidosis is a form of systemic amyloidosis, causing organ dysfunction, mainly affecting the heart and kidney. Patient-tailored and risk-adapted decision making is critical in AL amyloidosis management. There is limited real-world evidence data from Argentina and Latin America regarding the treatment approaches for AL amyloidosis. This retrospective cohort study aimed to describe the treatment patterns and outcomes in adult patients (>18 years) diagnosed with AL amyloidosis at the Hospital Italiano in Buenos Aires, Argentina, using a 10-yearfollow-up data (June 1, 2010 to May 31, 2019) from the institutional registry of amyloidosis (IRA). The study population had a mean age of 63 years and 54.4% weremale. Heart and kidney were the most frequently affected organs. Of the 90 eligible patients included in the study, 70underwent treatment. Bortezomib-based regimen was the preferred first-line treatment (75.7% patients). Overall,54.4% of the patients presented a deep response (complete or very good partial response). Median overall survival (OS) was 5years, the 1-year OS and progression free survival rates were 80% (95% confidence interval [CI]: 68–87) and 80% (95%CI 68–87)), respectively. This study provides vital real-world evidence for the long-term treatment patterns and survival in a large cohort of AL amyloidosis patients in Argentina.

Airway Amyloidosis: A Retrospective Analysis of 43 Patients

BACKGROUND

Amyloidosis can involve any compartment in the thorax. We aimed to explore the clinical and radiologic presentation, treatment, and clinical course of airway amyloidosis.

METHODS

A computer-assisted search was performed to identify patients who had biopsy-proven airway amyloidosis and were evaluated at Mayo Clinic in Rochester, MN, from January 1, 1997 through December 31, 2019. Demographic, clinical, and radiologic features along with clinical outcomes were analyzed.

RESULTS

We identified 43 patients who had airway amyloidosis. Median age was 60 years (range: 33 to 91 y), and 58% were female. Shortness of breath (63% of patients) and cough (44%) were the most common presenting symptoms. Most patients (82%) had localized amyloidosis with light chain being the most common amyloid type; 63% had tracheobronchial amyloidosis, and 23% had tracheal and upper airway involvement. On computed tomography of the chest, the most common findings were airway wall thickening with nodularity (60% of patients), airway calcification (53%), and airway occlusion without collapse (47%). On bronchoscopy (33 patients), the extent of amyloid involvement was most commonly submucosal (n=15) or nodular (n=8). External beam radiotherapy was the most common treatment modality. Among the 30 patients who had follow-up at our institution, the prognosis appeared to depend on the extent of the disease and whether patients had localized or systemic amyloidosis.

CONCLUSION

Computed tomography of the chest, bronchoscopy, and biopsy are needed to establish the diagnosis of airway amyloidosis, and systemic amyloidosis should be ruled out. Treatment of amyloidosis requires a multidisciplinary approach.

Unveiling Cardiac Amyloidosis, its Characteristics, and Outcomes Among Patients With MR Undergoing Transcatheter Edge-to-Edge MV Repair

BACKGROUND

Mitral regurgitation (MR) and cardiac amyloidosis (CA) both primarily affect older patients. Data on coexistence and prognostic implications of MR and CA are currently lacking.

OBJECTIVES

This study sought to identify the prevalence, clinical characteristics, and outcomes of MR CA compared with lone MR.

METHODS

Consecutive patients undergoing transcatheter edge-to-edge repair (TEER) for MR at 2 sites were screened for concomitant CA using a multiparametric approach including core laboratory 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid bone scintigraphy and echocardiography and immunoglobulin light chain assessment. Transthyretin CA (ATTR) was diagnosed by 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (Perugini grade 1: early infiltration; grades 2/3: clinical CA) and the absence of monoclonal protein, and light chain (AL) CA via tissue biopsy. All-cause mortality and hospitalization for heart failure (HHF) served as the endpoints.

RESULTS

A total of 120 patients (age 76.9 ± 8.1 years, 55.8% male) were recruited. Clinical CA was diagnosed in 14 patients (11.7%; 12 ATTR, 1 AL, and 1 combined ATTR/AL) and early amyloid infiltration in 9 patients (7.5%). Independent predictors of MR CA were increased posterior wall thickness and the presence of a left anterior fascicular block on electrocardiography. Procedural success and periprocedural complications of TEER were similar in MR CA and lone MR (P for all = NS). After a median of 1.7 years, 25.8% had experienced death and/or HHF. MR CA had worse outcomes compared with lone MR (HR: 2.2; 95% CI: 1.0-4.7; P = 0.034), driven by a 2.5-fold higher risk for HHF (HR: 2.5; 95% CI: 1.1-5.9), but comparable mortality (HR: 1.6; 95% CI: 0.4-6.1).

CONCLUSIONS

Dual pathology of MR CA is common in elderly patients with MR undergoing TEER and has worse postinterventional outcomes compared with lone MR.

Circulating biomarkers in diagnosis and management of cardiac amyloidosis: a review for internist

Cardiac amyloidosis (CA) is due to extracellular myocardial deposition of misfolded proteins resulting in severe cardiac dysfunction and death. The precursors of amyloid fibrils, able of determining a relevant cardiac infiltration, are immunoglobulin-free light chains (AL amyloidosis) and transthyretin (TTR) (both wild and mutated types). The diagnosis of amyloidosis represents a challenge for the clinician given its rarity and its protean clinical presentation, thus an early diagnosis remains a cornerstone for the prognosis of these patients, also in light of the growing available treatments. There is great interest in identifying and applying biomarkers to help diagnose, inform prognosis, guide therapy, and serve as surrogate endpoints in these patients. In AL amyloidosis, biomarkers such as free light chains, natriuretic peptides and troponins are the most extensively studied and validated; they have proved useful in risk stratification, guiding treatment choice and monitoring hematological and organ response. A similar biomarker-based prognostic score is also proposed for ATTR amyloidosis, although studies are small and need to be validated for wild-type and mutant forms.

Proposed Cardiac End Points for Clinical Trials in Immunoglobulin Light Chain Amyloidosis: Report From the Amyloidosis Forum Cardiac Working Group

Immunoglobulin light chain amyloidosis is a rare, multisystemic, phenotypically heterogenous disease affecting cardiovascular, renal, neurological, and gastrointestinal systems to varying degrees. Its underlying cause is a plasma cell dyscrasia characterized by misfolding of monoclonal immunoglobulin light chains which leads to aggregation and deposition of insoluble amyloid fibrils in target organs. Prognosis is primarily dependent on extent of cardiac involvement and depth of hematologic response to treatment. To facilitate development of new therapies, a public-private partnership was formed between the nonprofit Amyloidosis Research Consortium and the US Food and Drug Administration Center for Drug Evaluation and Research. In 2020, the Amyloidosis Forum launched an initiative to identify novel/composite end points and analytic strategies to expedite clinical trials for development of new therapies for the primary hematologic disorder and organ system manifestations. Specialized working groups identified organ-specific end points; additional working groups reviewed health-related quality of life measures and statistical approaches to data analysis. Each working group comprised amyloidosis experts, patient representatives, statisticians, and representatives from the Food and Drug Administration, the UK Medicines and Healthcare Products Regulatory Agency, and pharmaceutical companies. This review summarizes the proceedings and recommendations of the Cardiac Working Group. Using a modified Delphi method, the group identified, reviewed, and prioritized cardiac end points relevant to immunoglobulin light chain amyloidosis in the context of an antiplasma cell therapy. Prioritized cardiovascular end points included overall survival, hospitalization, N-terminal pro-B-type natriuretic peptide level, 6-minute walk test, Kansas City Cardiac Questionnaire, and cardiac deterioration progression-free survival. These recommended components will be further explored through evaluation of clinical trial datasets and formal guidance from regulatory authorities.

The Clinical Features and Outcomes of Renal Amyloidosis in Tunisia

Systemic amyloidosis is a rare disease characterized by clinical polymorphism. Indeed, the kidney is the most common organ involved and represents a real turning point in the disease. We aimed to determine the clinicopathological prognostic factors of renal amyloidosis (RA). We conducted a retrospective study including 40 cases with biopsy-proven RA collected in our department over a period of 10 years. Biochemical, demographic, and clinicopathological findings at diagnosis, as well as the follow-up data, were evaluated for each patient. The prevalence of amyloidosis was 2.7 per 100 nontransplant renal biopsies. The mean age at presentation was 55.5 ± 15.6 years with a male-to-female ratio of 1.85. The diagnosis of RA was confirmed by a renal biopsy in 85% of cases. Amyloid A (AA) amyloidosis was the most common type of amyloidosis (65%), and chronic infections ranked first in the panel of etiologies (41%). Amyloid light chain amyloidosis was mainly associated with multiple myeloma (57%). The median patient survival was 59 months versus 12 months for kidney survival. Age and extrarenal localization were independent predictors of mortality, whereas renal failure at presentation significantly influenced renal survival. The results of our study emphasize the rarity but also the severity of RA. AA amyloidosis was the most common type identified, which was mainly caused by chronic infections. Prevention remains the best solution until we can achieve therapeutic advances in inflammatory diseases.

Critical Comparison of Documents From Scientific Societies on Cardiac Amyloidosis: JACC State-of-the-Art Review

Over the last year, 5 national or international scientific societies have issued documents regarding cardiac amyloidosis (CA) to highlight the emerging clinical science, raise awareness, and facilitate diagnosis and management of CA. These documents provide useful guidance for clinicians managing patients with CA, and all include: 1) an algorithm to establish a diagnosis; 2) an emphasis on noninvasive diagnosis with the combined use of bone scintigraphy and the exclusion of a monoclonal protein; and 3) indications for novel disease-modifying therapies for symptomatic CA, either with or without peripheral neuropathy. Nonetheless, the documents diverge on specific details of diagnosis, risk stratification, and treatment. Highlighting the similarities and differences of the documents by the 5 scientific societies with respect to diagnosis, risk stratification, and treatment offers useful insight into the knowledge gaps and unmet needs in the management of CA. An analysis of these documents, therefore, highlights "gray zones" requiring further investigation.

COVID-19 and Light Chain Amyloidosis, Adding Insult to Injury

Light chain (AL) amyloidosis is a potentially fatal disease of monoclonal plasma cells that leads to accumulation of light chain amyloid fibrils, organ damage, and the manifestations of clinical disease. Meanwhile, coronavirus disease 2019 (COVID-19) is a disease caused by infection with the severe acute respiratory syndrome coronavirus 2 virus, with the potential to cause severe systemic illness and death. There is significant overlap in the demographics and comorbidities observed in AL amyloidosis and those associated with highest risk for severe morbidity and mortality due to COVID-19. This overlap creates unique challenges in caring for patients with AL amyloidosis, which are further compounded by the immunosuppressive nature of anti-plasma cell therapies, the need for frequent clinical assessments, and the exclusion of AL amyloidosis patients from initial COVID-19 vaccine trials. Herein, we highlight many of the relevant concerns related to COVID-19 and the treatment of AL amyloidosis, summarize a general approach for AL amyloidosis management amidst the ongoing COVID-19 pandemic, and discuss current guidance about COVID-19 vaccination of patients with AL amyloidosis.

Light Chain Amyloidosis: Epidemiology, Staging, and Prognostication

Amyloidosis is a disorder of protein misfolding and metabolism in which insoluble fibrils are deposited in various tissues, causing organ dysfunction and eventually death. Out of the 60-plus heterogeneous amyloidogenic proteins that have been identified, approximately 30 are associated with human disease. The unifying feature of these proteins is their tendency to form beta-pleated sheets aligned in an antiparallel fashion. These sheets then form rigid, nonbranching fibrils that resist proteolysis, causing mechanical disruption and local oxidative stress in affected organs such as the heart, liver, kidneys, nervous system, and gastrointestinal tract. Here we review the epidemiology of light chain amyloidosis, the staging, and the concomitant prognostication that is critical in determining the appropriate treatment.

Updates for the diagnosis and management of cardiac amyloidosis

A substantial increase in the interest in transthyretin cardiac amyloidosis (ATTR-CA) is a result of the constantly growing number of patients, the use of clear diagnostic protocols and the availability of the first selective drug for these patients. This has also raised the awareness of the disease among physicians of all specialties. The topic is particularly relevant to cardiologists, who use non-invasive multimodal imaging in their daily practice. The differential diagnosis of the causes of myocardial hypertrophy includes arterial hypertension, hypertrophic cardiomyopathy, aortic stenosis (AS), athletic heart syndrome, Fabry disease, and cardiac amyloidosis (CA). It turns out that in patients with myocardial hypertrophy >15 mm, amyloidosis is the most common cause of left ventricular (LV) hypertrophy. In parallel, CA is one of the most common infiltrative diseases leading to a clinical picture that may mimic heart failure with preserved ejection fraction (HFpEF). The accumulation of amyloid in the extracellular space impairs the diastolic function of the myocardium, which is observed as the restrictive cardiomyopathy phenotype. In advanced cases, the LV systolic function is also impaired. Moreover, protein deposits contribute to the disturbances of calcium metabolism and cell metabolism as well as to cardiotoxicity, leading to edema and damage to cardiomyocytes.

Cardiac amyloidosis: Description of a series of 143 cases

INTRODUCTION AND OBJECTIVES

Recently, there have been important advances in the diagnosis and treatment of cardiac amyloidosis (CA). Our aim was to provide an updated description of its 2 most frequent types: the transthyretin CA (ATTR-CA) and the light chain CA (AL-CA).

METHODS

Prospective registry of patients with CA diagnosed in 7 institutions in Galicia (Spain) between January 1, 2018 and June 30, 2020. Variables related to clinical characteristics, complementary tests, survival and causes of death were collected.

RESULTS

One hundred and forty-three patients with CA were consecutively included, 128 ATTR-CA (89.5%) and 15 AL-CA (10.5%). Mean age was 79.6±7.7 years and 23.8% were women. Most patients with ATTR-CA were diagnosed non-invasively (87.5%). On physical examination, 35.7, 35 and 7% had Popeye's sign, Dupuytren's contracture and macroglossia, respectively. Twelve-month and 24-month survival was 92.1 and 76.2% in the ATTR-CA group, and 78.6 and 61.1% in the AL-CA group (P=.152). The cause of death was cardiovascular in 80.8% of the cohort.

CONCLUSIONS

ATTR-CA can be diagnosed non-invasively in most cases and it is the most common type of CA in routine clinical practice. Furthermore, an increase in the short-term survival of CA appears to be observed, which could be due to advances related to its diagnosis and treatment.

[Recommendations for the treatment of AL amyloidosis]

INTRODUCTION

Immunoglobulin light chain (AL) amyloidosis is a rare disease. Treatment is challenging, justified in part by systemic compromise and limited scientific evidence.

OBJECTIVES

Develop evidencebased recommendations that allow adequate treatment of patients with amyloidosis AL.

METHODS

A list of PICO format questions focused on the effectiveness and safety of amyloidosis AL treatment was generated. PubMed, Cochrane and Epistemonikos were searched. The levels of evidence and grades of recommendation were based on the GRADE system.

RESULTS

11 recommendations were generated. In selected patients with amyloidosis AL, autologous hematopoietic stem cell transplantation (ASCT) is recommended after induction with bortezomibbased regimens and conditioning with melphalan, since it could deepen the hematological and organ response, its durability and improve survival. In patients not eligible for ASCT, first-line treatment with bortezomib-based regimens is recommended, since it is likely to achieve a higher rate of hematological and organ response and improve survival. In patients with a contraindication or inaccessibility to bortezomib, treatment with alkylating agents and corticosteroids is recommended, since they are likely to achieve haematological and organ response and improve survival.

DISCUSSION

These treatment recommendations are based on the available evidence and the experience of the panel of experts, in a scenario of limited available resources, according to developing countries.

Misconceptions and Facts About Cardiac Amyloidosis

Cardiac amyloidosis is an important clinical entity associated with significant morbidity and mortality. Although the signs and symptoms can be apparent early in the disease course, diagnoses are often made late because of inadequate recognition. A diagnosis of cardiac amyloidosis requires careful scrutiny of a patient's symptoms, an electrocardiogram, and imaging studies, including echocardiography and magnetic resonance imaging. Further evaluation is required through the measurement of serum and urine light chains and the use of bone scintigraphy imaging to differentiate transthyretin amyloidosis from light-chain cardiac amyloidosis. The available treatments have expanded tremendously in recent years and have improved outcomes in the population with this disorder. Thus, it has become increasingly important to diagnose cardiac amyloidosis and provide timely therapies. This article will clarify the various misconceptions about cardiac amyloidosis and provide a framework for primary care providers to better identify this disease in their practice.

Multimodality imaging approach to cardiac amyloidosis: part 2

With recent advances in cardiac imaging, genetics, and treatment options, cardiac amyloidosis (CA) is now recognized as an important and under diagnosed condition contributing to cardiovascular morbidity and mortality. Although still considered a rare disease, CA is now recognized as an important contributor to heart failure with preserved ejection fraction (HFPEF) and low gradient aortic stenosis, two important conditions commonly faced in clinical practice. This review uses clinical scenarios to highlight the complementary role of traditional imaging tools such as electrocardiogram (ECG) and echocardiography (echo) in conjunction with advanced cardiac imaging with cardiac magnetic resonance (CMR) and nuclear cardiac scintigraphy using bone avid tracers in the comprehensive workup of CA. We also highlight the importance of workup of light chain disease as part of integration of imaging findings and discuss the key aspects of various imaging modalities. Finally, an algorithm integrating clinical suspicion, laboratory testing, and imaging in the workup of CA is presented.