Attitudes about when and how to treat patients with AL amyloidosis: an international survey

Outcomes of patients with light chain (AL) amyloidosis after failure of daratumumab-based therapy

As daratumumab use in AL amyloidosis increases, more patients will either relapse after or become refractory to daratumumab. We present the outcome of 33 patients with AL who failed on daratumumab (due to haematological relapse in 21 [64%] patients and inadequate haematological response in 12 [36%]) and received further treatment. Overall response rate in the post-daratumumab failure treatment was 55% (CR/VGPR: 14 [42%] and PR: 3 [9%] patients). Patients retreated with daratumumab and patients harbouring +1q21 had lower rates of response. Treatment of patients with AL who fail daratumumab therapy is feasible when non-cross-resistant drugs or other targeted therapies are available.

Diagnostic and Treatment Strategies for AL Amyloidosis in an Era of Therapeutic Innovation

Despite significant progress and improving outcomes in the management of plasma cell disorders, AL amyloidosis remains diagnostically and therapeutically challenging for clinicians across practice settings. There is, however, a reason for optimism with the advent of new combination therapy approaches and novel targets offering the promise of improvement in end organ function, survival, and quality of life. This review offers a clinically applicable overview of an approach to diagnosis, risk stratification, and clinical management of AL amyloidosis in an era of rapid therapeutic innovation.

Diagnosis and Treatment of AL Amyloidosis

Systemic light chain (AL) amyloidosis is caused by an usually small B cell clone that produces a toxic light chain forming amyloid deposits in tissue. The heart and kidney are the major organs affected, but all others, with the exception of the CNS, can be involved. The disease is rapidly progressive, and it is still diagnosed late. Screening programs in patients followed by hematologists for plasma cell dyscrasias should be considered. The diagnosis requires demonstration in a tissue biopsy of amyloid deposits formed by immunoglobulin light chains. The workup of patients with AL amyloidosis requires adequate technology and expertise, and patients should be referred to specialized centers whenever possible. Stagings are based on cardiac and renal biomarkers and guides the choice of treatment. The combination of daratumumab, cyclophosphamide, bortezomib and dexamethasone (dara-CyBorD) is the current standard of care. Autologous stem cell transplant is performed in eligible patients, especially those who do not attain a satisfactory response to dara-CyBorD. Passive immunotherapy targeting the amyloid deposits combined with chemo-/immune-therapy targeting the amyloid clone is currently being tested in controlled clinical trials. Response to therapy is assessed based on validated criteria. Profound hematologic response is the early goal of treatment and should be accompanied over time by deepening organ response. Many relapsed/refractory patients are also treated with daratumumab combination, but novel regimens will be needed to rescue daratumumab-exposed subjects. Immunomodulatory drugs are the current cornerstone of rescue therapy, while immunotherapy targeting B-cell maturation antigen and inhibitors of Bcl-2 are promising alternatives.

Individualized Approach to Management of Light Chain Amyloidosis

Systemic light chain (AL) amyloidosis is caused by a B-cell (most commonly plasma cell) clone that produces a toxic light chain that forms amyloid fibrils in tissues and causes severe, progressive organ dysfunction. The clinical presentation is protean, and patients are usually extremely frail, thus requiring careful adaptation of the treatment approach. However, the severity of organ involvement can be accurately assessed with biomarkers that allow a sharp prognostic stratification and precise tailoring of the treatment strategy. Moreover, the availability of biomarker-based response criteria also allows adjustment of the treatment approach over time. The recent completion of 3 large randomized clinical trials has offered new evidence for designing appropriate treatments. All this information has recently been integrated in the joint guidelines of the International Society of Amyloidosis and the European Hematology Association for the treatment of AL amyloidosis. Other clinical trials are underway testing new agents directed against the amyloid clone and the amyloid deposits. Our understanding of the peculiarities of the amyloid clone, as well as our ability to detect residual clonal disease and improve organ dysfunction, are also being refined and will result in more precise personalization of the treatment approach.

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.

What Do the Elevated Protein Levels Mean in My Patients with Myeloma, Amyloidosis, and Related Disorders?

Multiple myeloma, light chain amyloidosis, and other plasma cell dyscrasias are characterized, in part, by abnormal production of paraproteins that are often responsible for the sequelae of those diseases. These paraproteins are whole or fragmented immunoglobulins produced by clonal antibody-secreting cells (usually plasma cells, but occasionally, B lymphocytes). Significant heterogeneity exists in the presentation of these diseases, ranging from incidental detection of a monoclonal protein in an asymptomatic patient, to life-threatening manifestations that require urgent diagnostic confirmation and intervention. Successful management of such scenarios requires a fundamental understanding of the laboratory assays at one's disposal, their role in the workup of paraproteinemias, and the interpretation thereof. This review broadly covers these assays and their roles in the diagnosis, prognosis, and management of these diseases.

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.

Progress in research: Daratumumab improves treatment outcomes of patients with AL amyloidosis

Outcomes for patients with systemic light-chain (AL) amyloidosis have improved over the last two decades with timely diagnosis, use of novel chemotherapeutic agents, risk stratification and better patient selection criteria before hematopoietic autologous stem cell transplant (ASCT). However, majority of patients have advanced stage disease at initial presentation and at relapse rendering them ineligible for intensive cytotoxic chemotherapy or ASCT. Daratumumab (Dara) with or without standard chemotherapy appears to be an excellent treatment option for newly diagnosed and relapsed refractory AL amyloidosis. This is largely due to its tolerable safety and remarkable efficacy as seen in multiple retrospective, small phase II studies as well as a phase III randomized controlled trial. Here we review published clinical trials and retrospective data of Dara in AL amyloidosis that explore its role as a valuable addition to the treatment armamentarium for this challenging disease.

Future Perspectives

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

Pomalidomide and dexamethasone grant rapid haematologic responses in patients with relapsed and refractory AL amyloidosis: a European retrospective series of 153 patients

Pomalidomide demonstrated activity in the treatment of AL amyloidosis in three phase II clinical trials. We evaluated the safety and efficacy of 28-day cycles of pomalidomide and dexamethasone in 153 previously treated patients with systemic AL amyloidosis. Ninety-nine (65%) were refractory to the last line of therapy and 54 (35%) had relapsed. The median number of previous lines of therapy was 3 (range: 2-7): 143 patients (93%) previously received bortezomib, 124 (81%) lenalidomide, 114 (75%) oral melphalan, and 37 (24%) underwent autologous stem cell transplant. At the completion of cycle 6, 68 (44%) patients obtained at least partial haematologic response, with 5 complete responses (CR, 3%), 35 very good partial responses (VGPR, 23%). Haematologic response resulted in improved overall survival (median survival 50 vs. 27 months, p = .033) in a 6 months landmark analysis. Obtaining at least partial response was also associated with a significant improvement of the progression-free survival (median PFS 37 vs. 18 months, p < .001). Pomalidomide is an effective treatment for heavily pre-treated patients with AL amyloidosis. Haematologic responses are associated with an overall survival advantage.

Performance of 99mTc-aprotinin scintigraphy for diagnosing light chain (AL) cardiac amyloidosis confirmed by endomyocardial biopsy

BACKGROUND

Light chain (AL) cardiac amyloidosis is associated with a poor prognosis. Diagnosing at an early stage is critical for treatment and the management of cardiac complication.

PURPOSE

We aimed to evaluate the diagnostic performance of 99mTc-aprotinin images in patients with AL cardiac amyloidosis.

METHODS AND RESULTS

99mTc-aprotinin scintigraphy and endomyocardial biopsy were performed in 10 patients with suspected amyloidosis. Endomyocardial biopsy showed amyloid deposits in 5 of 10 patients. 99mTc-aprotinin (planer image) was positive in 4 of 5 patients who had amyloid deposits in endomyocardial biopsy. On the other hand, all 5 patients without amyloid deposits were negative in planer image. 99mTc-aprotinin (SPECT/CT image) was positive in all 5 patients who had amyloid deposits.

CONCLUSIONS

99mTc-aprotinin scintigraphy is valuable for the non-invasive diagnosis of AL cardiac amyloidosis.

High rate of profound clonal and renal responses with daratumumab treatment in heavily pre-treated patients with light chain (AL) amyloidosis and high bone marrow plasma cell infiltrate

Daratumumab demonstrated activity in the treatment of AL amyloidosis in two recently concluded phase II clinical trials in relapsed and refractory patients. Its role in upfront therapy is under evaluation in a phase III study. In this report we evaluated the safety and efficacy of 28-day cycles of daratumumab (single agent or combined with bortezomib or lenalidomide) in 72 previously treated patients with multiple myeloma and AL amyloidosis. Fifty (69%) were refractory to the last line of therapy. After eight infusions of daratumumab, 59 patients (82%) achieved a hematologic response, with 12 (16%) complete responses (CRs) and 30 (42%) very good partial responses (VGPRs). After 16 infusions, the quality of response improved with 22 patients (30%) achieving CR and 21 (29%) attaining VGPR. Cardiac response was observed in 11 of 37 evaluable patients (29%) and renal response in 23 of 38 patients (60%). Daratumumab is highly effective in heavily pretreated patients with relapsed/refractory AL amyloidosis and high bone marrow plasma cell burden. Renal responses, which are usually rare in this setting, were frequently observed.

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.

Time to Redefine Risk-Stratification and Response Criteria in Immunoglobulin Light Chain Amyloidosis?

Immunoglobulin light chain (AL) amyloidosis results from clonal plasma cell (PC)-derived immunoglobulin light chain-mediated end-organ dysfunction, the extent and severity of which predicts survival. Anti-PC therapies reduce clonal light chain burden, which usually results in improvement of organ function, and consequently overall survival. Response assessment is critical to gauge therapeutic efficacy, to report clinical trial outcomes, and to switch therapy in those without response. Response in AL amyloidosis is 2-fold: hematologic response and organ response (OR). Depth of hematologic response is graded on the basis of serum free light chain (sFLC) parameters, but assessment of OR is binary. The role of normal sFLC ratio or complete remission as a treatment end point has been challenged, thus highlighting the need to quantify involved FLC and residual PC beyond the normal sFLC ratio to possibly account for the ongoing organ damage seen in some patients with complete remission. Mass spectrometry and urinary exosome represent ultrasensitive strategies to estimate involved FLC below the detection threshold of current sFLC assays. The role of new sFLC parameters and minimal residual disease as potential prognostic parameters has been recognized. Brain natriuretic peptide (BNP) and 24-hour proteinuria:estimated glomerular filtration rate ratio were identified to overcome certain limitations of N-terminal-Pro-BNP, 24-hour proteinuria, and estimated glomerular filtration rate for cardiac and renal response assessment, respectively. Use of monoclonal antibodies targeting PC and amyloid deposits has expanded the therapeutic armamentarium of AL amyloidosis, and given their excellent efficacy, early ORs are reported. This review provides insights into recent advances in the risk-stratification and response assessment of patients with AL amyloidosis in light of the changing therapeutic paradigms. Incorporation of these advancements into formal consensus guidelines would require further validation.

Amyloidosis in Heart Failure

PURPOSE

Amyloidosis represents an increasingly recognized but still frequently missed cause of heart failure. In the light of many effective therapies for light chain (AL) amyloidosis and promising new treatment options for transthyretin (ATTR) amyloidosis, awareness among caregivers needs to be raised to screen for amyloidosis as an important and potentially treatable differential diagnosis. This review outlines the diversity of cardiac amyloidosis, its relation to heart failure, the diagnostic algorithm, and therapeutic considerations that should be applied depending on the underlying type of amyloidosis.

RECENT FINDINGS

Non-biopsy diagnosis is feasible in ATTR amyloidosis in the absence of a monoclonal component resulting in higher detection rates of cardiac ATTR amyloidosis. Biomarker-guided staging systems have been updated to facilitate risk stratification according to currently available biomarkers independent of regional differences, but have not yet prospectively been tested. Novel therapies for hereditary and wild-type ATTR amyloidosis are increasingly available. The complex treatment options for AL amyloidosis are improving continuously, resulting in better survival and quality of life. Mortality in advanced cardiac amyloidosis remains high, underlining the importance of early diagnosis and treatment initiation. Cardiac amyloidosis is characterized by etiologic and clinical heterogeneity resulting in a frequently delayed diagnosis and an inappropriately high mortality risk. New treatment options for this hitherto partially untreatable condition have become and will become available, but raise challenges regarding their implementation. Referral to specialized centers providing access to extensive and targeted diagnostic investigations and treatment initiation may help to face these challenges.

When should treatment of AL amyloidosis start at relapse? Early, to prevent organ progression

This article has a companion Counterpoint by Sanchorawala.

Delay treatment of AL amyloidosis at relapse until symptomatic: devil is in the details

This article has a companion Point by Palladini and Merlini.

Emerging Therapeutics for the Treatment of Light Chain and Transthyretin Amyloidosis

Cardiac amyloidosis is a restrictive cardiomyopathy that results from the deposition of misfolded light chain or transthyretin proteins, most commonly, in cardiac tissue. Traditionally, treatment options for light chain (AL) and transthyretin (ATTR) amyloidosis have been limited. However, there are now multiple novel therapeutics in development and several therapeutics recently approved that promise to revolutionize clinical management of AL and ATTR. Most of these agents disrupt specific stages of amyloidogenesis such as light chain or transthyretin protein production, formation of amyloidogenic intermediates, or amyloid fibril aggregation. Others aim to remove existing amyloid tissue deposits using monoclonal antibody technology. Although these advances represent an important step forward in the care of cardiac amyloidosis patients, additional studies are needed to define the optimal treatment paradigms for AL and ATTR and to validate clinical, imaging, or serum biomarker strategies that may confirm a cardiac response to therapy.

Management of the elderly patient with AL amyloidosis

Systemic immunoglobulin light chain (AL) amyloidosis is an aging-associated protein misfolding and deposition disease. This condition is caused by a small and otherwise indolent plasma cell (or B cell) clone secreting an unstable circulating light chain, which misfolds and deposits as amyloid fibrils possibly leading to progressive dysfunction of affected organs. AL amyloidosis can occur in the typical setting of other, rarer forms of systemic amyloidosis and can mimic other more prevalent conditions of the elderly. Therefore, its diagnosis requires a high degree of clinical suspicion and reliable diagnostic tools for accurate amyloid typing, available at specialized referral centers. In AL amyloidosis, frailty is dictated by the type and severity of organ involvement, with heart involvement being the main determinant of morbidity and mortality. Still, given a similar disease stage, elderly patients with AL amyloidosis are often an even frailer group, due to significant comorbidities, associated disability and polypharmacotherapy, socioeconomic restrictions, and limited access to clinical trials. Recent improvements in the use of biomarkers for early diagnosis, risk stratification and response monitoring, the flourishing of novel, effective anti-plasma cell therapies developed against multiple myeloma and adapted to treat AL amyloidosis, and possibly the introduction of anti-amyloid therapies are rapidly changing the clinical management of this disease and are reflected by improved outcomes. Of note, hematologic and organ responses in elderly patients with AL amyloidosis do translate in better outcome, advocating the importance of treating these patients and striving for a rapid response to therapy also in this challenging clinical setting.

Systemic immunoglobulin light chain amyloidosis

Systemic immunoglobulin light chain amyloidosis is a protein misfolding disease caused by the conversion of immunoglobulin light chains from their soluble functional states into highly organized amyloid fibrillar aggregates that lead to organ dysfunction. The disease is progressive and, accordingly, early diagnosis is vital to prevent irreversible organ damage, of which cardiac damage and renal damage predominate. The development of novel sensitive biomarkers and imaging technologies for the detection and quantification of organ involvement and damage is facilitating earlier diagnosis and improved evaluation of the efficacy of new and existing therapies. Treatment is guided by risk assessment, which is based on levels of cardiac biomarkers; close monitoring of clonal and organ responses guides duration of therapy and changes in regimen. Several new classes of drugs, such as proteasome inhibitors and immunomodulatory drugs, along with high-dose chemotherapy and autologous haematopoietic stem cell transplantation, have led to rapid and deep suppression of amyloid light chain production in the majority of patients. However, effective therapies for patients with advanced cardiac involvement are an unmet need. Passive immunotherapies targeting clonal plasma cells and directly accelerating removal of amyloid deposits promise to further improve the overall outlook of this increasingly treatable disease.

Light Chain Amyloidosis

Light chain (AL) amyloidosis is caused by a usually small plasma-cell clone that is able to produce the amyloidogenic light chains. They are able to misfold and aggregate, deposit in tissues in the form of amyloid fibrils and lead to irreversible organ dysfunction and eventually death if treatment is late or ineffective. Cardiac damage is the most important prognostic determinant. The risk of dialysis is predicted by the severity of renal involvement, defined by the baseline proteinuria and glomerular filtration rate, and by the response to therapy. The specific treatment is chemotherapy targeting the underlying plasma-cell clone. It needs to be risk-adapted, according to the severity of cardiac and/or multi-organ involvement. Autologous stem cell transplant (preceded by induction and/or followed by consolidation with bortezomib-based regimens) can be considered for low-risk patients (~20%). Bortezomib combined with alkylators is used in the majority of intermediate-risk patients, and with possible dose escalation in high-risk subjects. Novel, powerful anti-plasma cell agents were investigated in the relapsed/refractory setting, and are being moved to upfront therapy in clinical trials. In addition, the use of novel approaches based on antibodies targeting the amyloid deposits or small molecules interfering with the amyloidogenic process gave promising results in preliminary studies. Some of them are under evaluation in controlled trials. These molecules will probably add powerful complements to standard chemotherapy. The understanding of the specific molecular mechanisms of cardiac damage and the characteristics of the amyloidogenic clone are unveiling novel potential treatment approaches, moving towards a cure for this dreadful disease.

Presentation and outcome with second-line treatment in AL amyloidosis previously sensitive to nontransplant therapies

Exposure to melphalan and bortezomib and quality of response to up-front treatment prolong time to second-line therapy in AL amyloidosis. Patients who need second-line therapy after initial response have a good outcome if they are rescued before cardiac progression.