Bendamustine With Dexamethasone in Relapsed/Refractory Systemic Light-Chain Amyloidosis: Results of a Phase II Study

Primary systemic amyloidosis: A brief overview

Primary systemic amyloidosis, or light chain (AL) amyloidosis, is a rare lymphoproliferative disorder in which aberrant light-chain immunoglobulins secreted into the bloodstream aggregate into fibrils and deposit into tissues, causing widespread organ damage and, if not treated, death. This review provides a comprehensive summary of the pathophysiology and manifestations of AL amyloidosis; standard-of-care diagnostic approach; typical treatment regimens; and areas of active investigation.

Optimizing drug therapies in cardiac amyloidosis

Cardiac amyloidosis (CA) is a form of infiltrative, restrictive cardiomyopathy that presents a diagnostic and therapeutic challenge in clinical practice. Historically, it has led to poor prognosis due to limited treatment options. However, advancements in disease awareness, diagnostic tools, and management approaches have led to the beginning of an era characterized by earlier diagnosis and a broader range of treatments. This article examines the advances in treating the two primary forms of cardiac amyloidosis: transthyretin cardiac amyloidosis (ATTR-CA) and light chain mediated cardiac amyloidosis (AL-CA). It highlights therapies for ATTR-CA that focus on interrupting the process of amyloid fibril formation. These therapies include transthyretin stabilizers, gene silencers, and monoclonal antibodies, which have shown the potential to improve patient outcomes and survival rates significantly. As of this writing, tafamidis is the sole Food and Drug Administration (FDA)--approved drug for ATTR-CA; however, experts anticipate several other drugs will gain approval within 1-2 years. Treatment strategies for AL-CA typically involve chemotherapy to inhibit the clonal cell type responsible for excessive AL amyloid fibril production. The prognosis for both types of amyloidosis primarily depends on how much the heart is affected, with most deaths occurring due to progressive heart failure. Effective care for CA patients requires collaboration among specialists from multiple disciplines, such as heart failure cardiology, electrophysiology, hematology/oncology, nephrology, neurology, pharmacology, and palliative care.

Light-chain (AL) amyloidosis for nephrologists-treatment standard

Amyloidosis is a group of complex diseases caused by the misfolding and aggregation of proteins into amyloid fibrils. Light-chain (AL) amyloidosis is one of the most prevalent forms of amyloidosis, characterized by the gradual proliferation of light chains from plasma cell clones. A growing body of evidence has contributed to our understanding of its pathogenesis, presentation and clinical course. Increased recognition of its clinical sequelae has increased the prevalence of AL amyloidosis. Renal involvement, seen in up to 70% of cases, is particularly challenging due to its impact on quality of life and access to treatment options. Thus, early recognition of its unique sequelae, appropriate staging and a comprehensive understanding of treatment options balanced by their organ toxicities are crucial to managing this disease. We review the current treatment standards and discuss novel developments in the pathophysiology, diagnosis, outcome prediction and management of AL amyloidosis for the Nephrologist.

Advances in the Therapy of Light Chain Cardiac Amyloidosis

Systemic light chain (AL) amyloidosis stems from abnormal production of amyloidogenic immunoglobulin light chains by plasma cells or B-cell disorders. It can present locally or systemically, with systemic forms posing significant mortality risks, especially if cardiac involvement is present. Delayed diagnosis due to nonspecific symptoms leads to progressive organ dysfunction. Early recognition is vital for timely treatment, aiming to suppress amyloid production and reduce organ damage, thus promoting recovery and improving survival rates. This review article provides a comprehensive overview of the recent advancements in medical therapy for patients with AL cardiac amyloidosis.

Cardiac Toxicity in the Treatment of Light Chain Amyloidosis: Systematic Review of Clinical Studies

BACKGROUND

Light chain amyloidosis (AL) is a progressive and a fatal disease that primarily affects cardiac tissue. Although the current approach to anti-amyloidosis treatments has managed to reduce amyloidosis morbimortality, the dynamics of cardiac adverse events are unknown.

OBJECTIVE

to provide evidence about reported cardiac toxicity during treatment of AL amyloidosis through a systematic review of the literature.

METHODS

A search was performed for registered clinical trials on ClinicalTrials.gov filtered for AL amyloidosis up to December 31, 2022. Studies were filtered by those that reported intervention in patients with AL amyloidosis and that had reported adverse events. The type of study, the intervention performed, and the frequency of reported cardiac adverse events were discriminated from each trial.

RESULTS

25 clinical trials were analyzed, representing a population of 1,542 patients, among whom 576 (38.95%) adverse events were reported, 326 being serious (SAE) and 242 nonserious (nSAE). The most frequent SAEs were cardiac failure, atrial fibrillation, and cardiac arrest, while the most frequent nSAEs were palpitations, atrial fibrillation, and sinus tachycardia.

CONCLUSION

cardiac toxicity during treatment for amyloidosis seems common, and it is important to evaluate the relationship of therapies with its occurrence.

Cardiac amyloidosis: evolving pathogenesis, multimodal diagnostics, and principles of treatment

Amyloidosis is a protein deposition disorder in which insoluble fibril structures accumulate in the bodily tissues damaging the organ function. Cardiac amyloidosis is a severe but under-reported medical condition characterized by the accumulation of amyloid in the extracellular area of the myocardium, which results in thickening and stiffening of ventricular walls. Cardiac amyloidosis has recently gained much attention with its slowly surging incidence. With this study, we seek to comprehensively compile the pathophysiology and clinical picture of cardiac amyloidosis subtypes, extending a clinically oriented, up-to-date clinical approach to diagnosis and therapy. Cardiac amyloidosis can be caused by rare genetic mutations which may be inherited or acquired. The growing incidence can be attributed to advancements in imaging methods and other diagnostic modalities. Most occurrences of cardiac amyloidosis result from two forms of precursor protein: transthyretin [TTR] amyloid and immunoglobulin-derived light-chain amyloid. Prompt identification of cardiac amyloidosis can facilitate the implementation of evolving therapeutic interventions to enhance the outcomes. The modalities for the management of CA have evolved significantly in the last ten years. Apart from therapies for modifying disease and heart failure, a myriad of novel therapeutic approaches that target specific aspects of the disease, including gene therapies, are being researched. These aim at impeding its progression and improving clinical outcomes. See also Figure 1(Fig. 1).

Status and Future Directions of Therapeutics and Prognosis of Cardiac Amyloidosis

Accumulation of aberrant proteins in the heart causes cardiac amyloidosis, an uncommon and complicated illness. It can be classified into two main types: light chain (AL) and transthyretin (ATTR). The diagnosis of cardiac amyloidosis is challenging due to its non-specific clinical presentation and lack of definitive diagnostic tests. Diagnostic accuracy has increased with the advent of modern imaging methods, including cardiac magnetic resonance imaging (MRI) and positron emission tomography (PET) scans. Depending on the severity of cardiac amyloidosis, a number of treatments may be attempted and specified according to the subtype of amyloidosis and the presence of complications. However, there are still significant challenges in treating this condition due to its complexity and lack of effective treatments. The prognosis for patients with cardiac amyloidosis is poor. Despite recent advances in diagnosis and treatment, there is still a need for more effective treatments to improve outcomes for patients with this condition. Therefore, we aim to review the current and future therapeutics reported in the literature and among ongoing clinical trials recruiting patients with CA.

Guidelines for non-transplant chemotherapy for treatment of systemic AL amyloidosis: EHA-ISA working group

BACKGROUND

This guideline has been developed jointly by the European Society of Haematology and International Society of Amyloidosis recommending non-transplant chemotherapy treatment for patients with AL amyloidosis.

METHODS

A review of literature and grading of evidence as well as expert recommendations by the ESH and ISA guideline committees.

RESULTS AND CONCLUSIONS

The recommendations of this committee suggest that treatment follows the clinical presentation which determines treatment tolerance tempered by potential side effects to select and modify use of drugs in AL amyloidosis. All patients with AL amyloidosis should be considered for clinical trials where available. Daratumumab-VCD is recommended from most untreated patients (VCD or VMDex if daratumumab is unavailable). At relapse, the two guiding principles are the depth and duration of initial response, use of a class of agents not previously exposed as well as the limitation imposed by patients' fitness/frailty and end organ damage. Targeted agents like venetoclax need urgent prospective evaluation. Future prospective trials should include advanced stage patients to allow for evidence-based treatment decisions. Therapies targeting amyloid fibrils or those reducing the proteotoxicity of amyloidogenic light chains/oligomers are urgently needed.

AL Amyloidosis for Cardiologists: Awareness, Diagnosis, and Future Prospects: JACC: CardioOncology State-of-the-Art Review

Amyloid light chain (AL) amyloidosis is a rare, debilitating, often fatal disease. Symptoms of cardiomyopathy are common presenting features, and patients often are referred to cardiologists. Cardiac amyloid infiltration is the leading predictor of death. However, the variable presentation and perceived rarity of the disease frequently lead to delay in suspecting amyloidosis as a cause of heart failure, leading to misdiagnoses and a marked delay in diagnosis, with devastating consequences for the patient. A median time from symptom onset to correct diagnosis of about 2 years is often too long when median survival from diagnosis for patients with AL amyloidosis and cardiomyopathy is 4 months to 2 years. The authors highlight the challenges to diagnosis, identify gaps in the current knowledge, and summarize novel treatments on the horizon to raise awareness about the critical need for early recognition of symptoms and diagnosis of AL amyloidosis aimed at accelerating treatment and improving outcomes for patients.

Advances in the treatment of light chain amyloidosis

PURPOSE OF REVIEW

After many years, the management of systemic light chain (AL) amyloidosis is entering the era of evidence-based medicine, with three recently published randomized clinical trials, a regimen (daratumumab, cyclophosphamide, bortezomib, and dexamethasone, daratumumab-CyBorD) labeled for upfront therapy, more clinical trials ongoing, and published guidelines. In this review, we discuss how current practice is changing based on this data.

RECENT FINDINGS

Daratumumab-CyBorD grants unprecedentedly high rates of hematologic and organ response and became the novel standard-of-care in AL amyloidosis. The International Society of Amyloidosis and the European Hematology Association issued common guidelines for autologous stem cell transplant (ASCT) in this disease. Improved patient selection and effective induction regimens greatly reduced ASCT-related mortality. Venetoclax is emerging as a very effective option in patients harboring the common t(11;14) abnormality. Rapid and profound reduction of the amyloid free light chain can improve survival also at advanced stages.

SUMMARY

Daratumumab-CyBorD is being integrated into the treatment flow-chart whereas the role of ASCT is being redefined. New approaches are being tested in clinical trials. Treatment of daratumumab-refractory patients and validation of criteria of hematologic progression to be used in clinical trials and in individual patient management are current areas of research.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.

Update on the Contemporary Treatment of Light Chain Amyloidosis Including Stem Cell Transplantation

The management of immunoglobulin light chain (AL) amyloidosis is complex. Emerging data have shown promising results for several novel agents. We review the management of AL amyloidosis, including factors that determine transplant eligibility, treatment options for transplant-ineligible patients, and treatment options for relapsed/refractory AL amyloidosis. For carefully selected patients, high-dose melphalan and stem cell transplantation is recommended. Transplant eligibility criteria generally include biopsy-proven amyloidosis, evidence of a plasma cell dyscrasia, involvement of at least one major organ, and adequate performance status. For transplant-ineligible patients, bortezomib-based regimens are recommended, including: 1) bortezomib, oral melphalan, and dexamethasone (BMDex); 2) bortezomib, cyclophosphamide, and dexamethasone (CyBorD or VCd); and 3) subcutaneous daratumumab (DARA SC) and VCd. The latter option is based on a landmark trial that led to the first US Food and Drug Administration-approved therapy for AL amyloidosis. For relapsed/refractory disease, novel therapeutics including proteosome inhibitors, immunomodulatory agents, and monoclonal antibodies have shown promising results. In this review, we summarize data for various therapeutics in different clinical scenarios of AL amyloidosis.

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

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

How I Treat AL Amyloidosis

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

Current Updates on the Management of AL Amyloidosis

Systemic immunoglobulin light chain (AL) amyloidosis is a rare but fatal disease. It results from clonal proliferation of plasma cells with excessive production of insoluble misfolded proteins that aggregate in the extracellular matrix, causing damage to the normal architecture and function of various organs. For decades, treatment for AL amyloidosis was based mainly on therapeutic agents previously studied for its more common counterpart, multiple myeloma. As the prevalence and incidence of AL amyloidosis have increased, ongoing research has been conducted with treatments typically used in myeloma with varying success. In this review, we focus on current treatment strategies and updates to clinical guidelines and therapeutics for AL amyloidosis.

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

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

Comprehensive Review of AL amyloidosis: some practical recommendations

Amyloid light chain (AL) amyloidosis is among the more common and more severe of the amyloidoses usually involving the slow proliferation of a bone-marrow-residing plasma cell (PC) clone and the secretion of unstable immunoglobulin-free light chains (FLC) that infiltrate peripheral tissues and result in detrimental end-organ damage. Disease presentation is rather vague, and the hallmark of treatment is early diagnosis before irreversible end-organ damage. Once diagnosed, treatment decision is transplant-driven whereby ~20% of patients are eligible for autologous stem cell transplantation (ASCT) with or without bortezomib-based induction. In the setting of ASCT-ineligibility, bortezomib plays a central role in upfront treatment with the recent addition of daratumumab to the current emerging standard of care. In general, management of AL amyloidosis is aimed at achieving deep, durable responses with very close monitoring for early detection of relapse/refractory disease. This article provides a comprehensive review of the management of patients with AL amyloidosis including goals of therapy, current treatment guidelines in the setting of both ASCT-eligibility and ineligibility, treatment response monitoring recommendations, toxicity management, and treatment of relapse/refractory disease.

Immunoglobulin light chain amyloidosis diagnosis and treatment algorithm 2021

Immunoglobulin light chain amyloidosis (AL) commonly presents with nephrotic range proteinuria, heart failure with preserved ejection fraction, nondiabetic peripheral neuropathy, unexplained hepatomegaly or diarrhea, and should be considered in patients presenting with these symptoms. More importantly, patients being monitored for smoldering multiple myeloma and a monoclonal gammopathy of undetermined significance (MGUS) are at risk for developing AL amyloidosis. MGUS and myeloma patients that have atypical features, including unexplained weight loss; lower extremity edema, early satiety, and dyspnea on exertion should be considered at risk for light chain amyloidosis. Overlooking the diagnosis of light chain amyloidosis leading to therapy delay is common, and it represents an error of diagnostic consideration. Herein we provide a review of established and investigational treatments for patients with AL amyloidosis and provide algorithms for workup and management of these patients.

Pathophysiology and Therapeutic Approaches to Cardiac Amyloidosis

Often considered a rare disease, cardiac amyloidosis is increasingly recognized by practicing clinicians. The increased rate of diagnosis is in part due the aging of the population and increasing incidence and prevalence of cardiac amyloidosis with advancing age, as well as the advent of noninvasive methods using nuclear scintigraphy to diagnose transthyretin cardiac amyloidosis due to either variant or wild type transthyretin without a biopsy. Perhaps the most important driver of the increased awareness is the elucidation of the biologic mechanisms underlying the pathogenesis of cardiac amyloidosis which have led to the development of several effective therapies with differing mechanisms of actions. In this review, the mechanisms underlying the pathogenesis of cardiac amyloidosis due to light chain (AL) or transthyretin (ATTR) amyloidosis are delineated as well as the rapidly evolving therapeutic landscape that has emerged from a better pathophysiologic understanding of disease development.

Management of AL amyloidosis in 2020

In amyloid light chain (AL) amyloidosis, a small B-cell clone, most commonly a plasma cell clone, produces monoclonal light chains that exert organ toxicity and deposit in tissue in the form of amyloid fibrils. Organ involvement determines the clinical manifestations, but symptoms are usually recognized late. Patients with disease diagnosed at advanced stages, particularly when heart involvement is present, are at high risk of death within a few months. However, symptoms are always preceded by a detectable monoclonal gammopathy and by elevated biomarkers of organ involvement, and hematologists can screen subjects who have known monoclonal gammopathy for amyloid organ dysfunction and damage, allowing for a presymptomatic diagnosis. Discriminating patients with other forms of amyloidosis is difficult but necessary, and tissue typing with adequate technology available at referral centers, is mandatory to confirm AL amyloidosis. Treatment targets the underlying clone and should be risk adapted to rapidly administer the most effective therapy patients can safely tolerate. In approximately one-fifth of patients, autologous stem cell transplantation can be considered up front or after bortezomib-based conditioning. Bortezomib can improve the depth of response after transplantation and is the backbone of treatment of patients who are not eligible for transplantation. The daratumumab+bortezomib combination is emerging as a novel standard of care in AL amyloidosis. Treatment should be aimed at achieving early and profound hematologic response and organ response in the long term. Close monitoring of hematologic response is vital to shifting nonresponders to rescue treatments. Patients with relapsed/refractory disease are generally treated with immune-modulatory drugs, but daratumumab is also an effective option.

Recent advances in the diagnosis and management of amyloid cardiomyopathy

Amyloidosis is a disorder characterized by misfolded precursor proteins that form depositions of fibrillar aggregates with an abnormal cross-beta-sheet conformation, known as amyloid, in the extracellular space of several tissues. Although there are more than 30 known amyloidogenic proteins, both hereditary and non-hereditary, cardiac amyloidosis (CA) typically arises from either misfolded transthyretin (ATTR amyloidosis) or immunoglobulin light-chain aggregation (AL amyloidosis). Its prevalence is more common than previously thought, especially among patients with heart failure and preserved ejection fraction (HFpEF) and aortic stenosis. If there is a clinical suspicion of CA, focused echocardiography, laboratory screening for the presence of a monoclonal protein (serum and urinary electrophoresis with immunofixation and serum free light-chain ratio), and cardiac scintigraphy with 99mtechnetium-labeled bone-tracers are sensitive and specific initial diagnostic tests. In some cases, more advanced/invasive techniques are necessary and, in the last several years, treatment options for both AL CA and ATTR CA have rapidly expanded. It is important to note that the aims of therapy are different. Systemic AL amyloidosis requires treatment targeted against the abnormal plasma cell clone, whereas therapy for ATTR CA must be targeted to the production and stabilization of the TTR molecule. It is likely that a multistep treatment approach will be optimal for both AL CA and ATTR CA. Additionally, treatment of CA includes the management of restrictive cardiomyopathy with preserved or reduced ejection fraction in addition to treating the amyloid deposition. Future studies are necessary to define optimal management strategies for AL CA and ATTR CA and confirm cardiac response to therapy.

A safety review of drug treatments for patients with systemic immunoglobulin light chain (AL) amyloidosis

INTRODUCTION

In AL amyloidosis, a usually small plasma cell clone secretes unstable, amyloid-forming light chains, causing cytotoxicity and progressive (multi)organ function deterioration. Treatment aims at reducing/eradicating the underlying clone, to reduce/zero the supply of the amyloidogenic protein and halt the amyloidogenic cascade.

AREAS COVERED

Safety data of alkylating agents, proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies from clinical trials are reviewed.

EXPERT OPINION

Drugs used to treat AL amyloidosis are derived from experience with multiple myeloma or other B cell malignancies. However, treating AL amyloidosis is particularly challenging, as it implies delivering anti-neoplastic therapy to a hematologic malignancy directly causing (multi)organ function deterioration, often in elderly subjects with other comorbidities and polypharmacotherapy. This unique combination translates in increased patients' frailty and higher sensitivity toward treatment-related toxicities. Therefore, dose/schedule adjustments and special precautions are needed when translating treatment experience from multiple myeloma or other B cell malignancies to AL amyloidosis. Treatment of patients with AL amyloidosis should be risk adapted, tailored to individual patients' risk profile, considering the type and extent of organ involvement, and eventual comorbidity. As several classes of effective anti-plasma cell or B cell drugs are available, therapeutic choices are also influenced by individual drug's safety profile.

Beyond Andromeda: Improving Therapy for Light Chain Amyloidosis

Therapy for light chain amyloidosis (AL) continues to evolve, and a new standard of care for the disease is rapidly forming. The risk of early death however, mainly from cardiac complications, remains an important benchmark yet to be definitively improved upon. This brief review explores recent advances in plasma cell directed therapy for AL, highlighting unique factors specific to these patients and AL biology driving differences in treatment strategies and clinical development compared with multiple myeloma. Improving upon proteasome inhibitor based upfront therapy combinations with the addition of anti-CD38 antibodies has shown promise with improved response rates in the ANDROMEDA (NCT03201965) study. Though depth and kinetics of achieving deep hematologic response as well as rates of biomarker defined organ response were improved with the addition of daratumumab to the combination of bortezomib, cyclophosphamide, and dexamethasone, death rates in each arm remained similar. Evaluation of other targeted and novel therapies in AL is ongoing, and we highlight efforts evaluating B-cell maturation antigen (BCMA) directed therapy, BCL-2 family inhibitors, and other novel agents in the field. We also look ahead to efforts to reimagine the clinical development of anti-fibrillar therapies after late phase study failures. Upcoming anti-amyloid fibril antibody studies explore opportunities to improve outcomes for the sickest AL patients with advanced cardiac disease, focusing on improving overall patient survival and reducing the risk of early death in this uniquely frail population.

Venetoclax induces deep hematologic remissions in t(11;14) relapsed/refractory AL amyloidosis

Venetoclax is efficacious in relapsed/refractory t(11;14) multiple myeloma, thus warranting investigation in light-chain amyloidosis (AL). This retrospective cohort includes 43 patients with previously treated AL, from 14 centers in the US and Europe. Thirty-one patients harbored t(11;14), 11 did not, and one t(11;14) status was unknown. Patients received a venetoclax-containing regimen for at least one 21- or 28-day cycle; the median prior treatments was three. The hematologic response rate for all patients was 68%; 63% achieved VGPR/CR. t(11;14) patients had higher hematologic response (81% vs. 40%) and higher VGPR/CR rate (78% vs. 30%, odds ratio: 0.12, 95% CI 0.02–0.62) than non-t(11;14) patients. For the unsegregated cohort, median progression-free survival (PFS) was 31.0 months and median OS was not reached (NR). For t(11;14), median PFS was NR and for non-t(11;14) median PFS was 6.7 months (HR: 0.14, 95% CI 0.04–0.53). Multivariate analysis incorporating age, sex, prior lines of therapy, and disease stage suggested a risk reduction for progression or death in t(11;14) patients. Median OS was NR for either subgroup. The organ response rate was 38%; most responders harbored t(11;14). Grade 3 or higher adverse events occurred in 19% with 7% due to infections. These promising results require confirmation in a randomized clinical trial.

Management of AL amyloidosis in 2020

In amyloid light chain (AL) amyloidosis, a small B-cell clone, most commonly a plasma cell clone, produces monoclonal light chains that exert organ toxicity and deposit in tissue in the form of amyloid fibrils. Organ involvement determines the clinical manifestations, but symptoms are usually recognized late. Patients with disease diagnosed at advanced stages, particularly when heart involvement is present, are at high risk of death within a few months. However, symptoms are always preceded by a detectable monoclonal gammopathy and by elevated biomarkers of organ involvement, and hematologists can screen subjects who have known monoclonal gammopathy for amyloid organ dysfunction and damage, allowing for a presymptomatic diagnosis. Discriminating patients with other forms of amyloidosis is difficult but necessary, and tissue typing with adequate technology available at referral centers, is mandatory to confirm AL amyloidosis. Treatment targets the underlying clone and should be risk adapted to rapidly administer the most effective therapy patients can safely tolerate. In approximately one-fifth of patients, autologous stem cell transplantation can be considered up front or after bortezomib-based conditioning. Bortezomib can improve the depth of response after transplantation and is the backbone of treatment of patients who are not eligible for transplantation. The daratumumab+bortezomib combination is emerging as a novel standard of care in AL amyloidosis. Treatment should be aimed at achieving early and profound hematologic response and organ response in the long term. Close monitoring of hematologic response is vital to shifting nonresponders to rescue treatments. Patients with relapsed/refractory disease are generally treated with immune-modulatory drugs, but daratumumab is also an effective option.

Systemic Amyloidosis due to Low-Grade Lymphoma

Lymphoma-related amyloidosis is a rare entity. Systemic AL amyloidosis is generally caused by an underlying plasma cell clone in the bone marrow with an intact monoclonal immunoglobulin G (IgG) or IgA protein. The rarity of the lymphoma-related amyloidosis makes the generation of data in randomized trials and the determination of the optimal treatment almost impossible. Therefore, treatment recommendations discussed here are based on either retrospective or small prospective trials of single centers.

Options for Chemotherapy and Scoring Response and Relapse

Chemotherapy for amyloid light chain (AL) amyloidosis has evolved over the years. Although high-dose melphalan and stem cell transplantation remain the standard of care for eligible patients, a vast majority of the patients at the time of presentation are not eligible for this approach and require low-intensity but highly effective induction therapy, usually based on bortezomib. Immunomodulatory agents are not well tolerated, particularly by patients with AL amyloidosis cardiomyopathy, and are reserved for second-line or later therapy. Because there currently is no Food Drug and Administration-approved therapy, participation in well-designed clinical trials of high scientific merit should be considered.

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.

Systemic AL Amyloidosis: Current Approaches to Diagnosis and Management

AL amyloidosis is characterized by a low-level expansion of an indolent, small plasma cell clone that produces amyloidogenic light chains. Amyloid aggregates or preceding intermediaries cause direct cell damage through their proteotoxicity, and amyloid deposits distort tissue architecture, and, eventually, lead to organ impairment. It is a rare, underdiagnosed disease with a diverse clinical presentation depending on the organ tropism of the amyloid fibrils; cardiac and renal involvement is most common, but any organ can be affected, excluding the central nervous system. A high level of awareness and a systematic approach using newly emerging screening biomarkers is required to achieve early diagnosis. Management should be multidisciplinary as supportive management tailored to management of organ dysfunction is paramount to survival and minimization of treatment-associated toxicity. The initial therapeutic aim is to rapidly eliminate the clonal plasma cell that produces the circulating amyloid precursor and achieve a complete hematologic response, and if possible with undetectable minimal residual disease as assessed by next-generation methods (flow and sequencing), with minimal toxicity. Treatment is tailored to the initial risk assessment of the patients. Treatments are based on regimens adapted from the expanding options that are available for multiple myeloma patients and hematological response rates have improved. Organ response rates are strongly associated with deeper hematologic response but usually lag behind hematological response and are also dependent on the initial organ function reserve. Agents directed against the amyloid deposits have been explored to aid amyloid clearance and improve organ function, but data are still negative.

Novel challenges in the management of immunoglobulin light chain amyloidosis: from the bench to the bedside

INTRODUCTION

Immunoglobulin light chain (AL) amyloidosis is one of the most frequent systemic amyloidosis in Western countries. It is caused by a B-cell clone producing a misfolded light chain (LC) that deposits in organs.

AREAS COVERED

The review examines recent findings on pathophysiology and clinical management of AL amyloidosis. It contains an update on the recent hot topics as novel therapeutic approaches, definition of relapse, and hematologic response assessment. To review literature on AL amyloidosis, a bibliographic search was performed using PubMed.

EXPERT OPINION

Due to the proteotoxicity of amyloidogenic LCs, the therapeutic goal is a rapid and profound decrease in their concentration. The standard treatment is a risk-adapted chemotherapy targeting the B-cell clone. Novel, promising drugs, as daratumumab, are currently under evaluation in newly-diagnosed and relapsed/refractory patients. New sensitive techniques, as mass spectrometry approach and bone marrow minimal residual disease assessment, are available to evaluate depth of response. After first-line therapy, increase in LC concentration may precede worsening of organ dysfunction and should be considered carefully. Further clarification of molecular mechanisms of the disease are shedding light on new possible therapeutic targets. Innovative treatment strategies and novel technologies will improve our ability to treat AL amyloidosis, preventing organ deterioration.

Diagnosis and management of systemic light chain AL amyloidosis

AL amyloidosis is a plasma cell disorder leading to the production and extracellular deposition of abnormal immunoglobulin light chains called amyloid. The pathogenesis of the disorder is driven by an abnormal plasma cell clone producing excessive monoclonal immunoglobulin light chains that undergo deposition in various organs of the body such as the heart, kidney, and gastrointestinal tract. The outcome of the disease remains poor with significant morbidity and mortality associated with organ dysfunction. In this review, we describe the current standard diagnostic features, prognosis, and current treatment paradigm of the disease.