An overview of the use of high-dose melphalan with autologous stem cell transplantation for the treatment of AL amyloidosis.

Primary or AL amyloidosis results from a plasma cell dyscrasia in which fibrillar light chain protein deposition leads to organ failure and death. Standard treatment for AL amyloidosis has been oral melphalan and prednisone. However, this form of treatment modifies the natural history of this lethal disease only marginally, extending median survival from 13 months following diagnosis to 17 months. At Boston University Medical Center, we have developed treatment protocols using high-dose intravenous melphalan with autologous peripheral blood stem cell transplantation (HDM/SCT) to treat AL amyloidosis, and we have treated over 200 patients with HDM/SCT during the past six years. This extensive experience has shown that patients with AL amyloidosis, despite multisystem involvement and compromised organ function can tolerate this aggressive form of treatment. Furthermore, HDM/SCT results in durable hematologic responses in a substantial proportion of patients, and such responses are associated with clinical improvement, decreased amyloid-related organ dysfunction, and prolonged survival. However, toxicity from treatment is high (overall peri-transplant mortality, 14%), particularly for those patients with clinically significant cardiac involvement. For this reason, we believe a multidisciplinary management approach is essential when using HDM/SCT for treatment of AL amyloidosis. Based on our experience, we believe that HDM/SCT is the treatment of choice for patients with AL amyloidosis who have a good performance status and limited cardiac involvement at the time of diagnosis. HDM/SCT offers the best chance for hematologic remission, prolongation of survival, and reversal of amyloid-related disease. At the same time, we believe that HDM/SCT should continue to be examined in the context of clinical trials, directed at developing approaches to broaden the applicability of this therapy by minimizing toxicity and to increase the likelihood of complete hematologic responses.     

Short and long-term outcome of treatment with high-dose melphalan and stem cell transplantation for multiple myeloma-associated AL amyloidosis

High-dose melphalan chemotherapy and autologous peripheral blood stem cell transplantation (HDM/SCT) has been shown to result in a durable hematologic response and prolonged overall survival in systemic amyloid light-chain (AL) amyloidosis as well as multiple myeloma. However, little is known about the myeloma associated with AL amyloidosis (MM/AL). In this retrospective study, we evaluated 87 patients with MM/AL from 1994 to 2007. Sixteen of these patients underwent HDM/SCT at Boston University Medical Center. Three patients (19%) died from treatment-related mortality. The overall median survival for all 87 patients was 22 months by Kaplan–Meier estimates. However, this was improved to 54.5 months for those who received HDM/SCT compared to 21 months for those who did not receive HDM/SCT. A hematologic complete response was achieved by 25% (4/16) of patients at 6 months after HDM/SCT. Hematologic relapses occurred in 60% of patients at a median of 1 year after HDM/SCT. In conclusion, HDM/SCT can prolong overall survival in patients with MM/AL who are eligible to receive it.     

High-dose intravenous melphalan and autologous stem cell transplantation as initial therapy or following two cycles of oral chemotherapy for the treatment of AL amyloidosis: results of a prospective randomized trial

Summary:A prospective randomized trial was conducted to study the timing of high-dose intravenous melphalan and autologous stem cell transplantation (HDM/SCT) in AL amyloidosis. In all, 100 newly diagnosed patients were randomized to receive HDM/SCT, either as initial therapy (Arm-1) or following two cycles of oral melphalan and prednisone (Arm-2). The objectives of the trial were to compare survival and hematologic and clinical responses. With a median follow-up of 45 months (range 24-70), the overall survival was not significantly different between the two treatment arms (P=0.39). The hematologic response and organ system improvements after treatment did not differ between the two groups. Fewer patients received HDM/SCT in Arm-2 because of disease progression during the oral chemotherapy phase of the study, rendering them ineligible for subsequent high-dose therapy. This affected patients with cardiac involvement particularly, and led to a trend for an early survival disadvantage in Arm-2. Hence, newly diagnosed patients with AL amyloidosis eligible for HDM/SCT did not benefit from initial treatment with oral melphalan and prednisone, and there was a survival disadvantage for patients with cardiac involvement if HDM/SCT was delayed by initial oral chemotherapy.     

Tandem cycles of high-dose melphalan and autologous stem cell transplantation increases the response rate in AL amyloidosis

Clinical outcomes of patients with AL amyloidosis treated with high-dose melphalan and stem cell transplantation (HDM/SCT) are tightly linked to the achievement of a hematologic complete response (HCR). We conducted a prospective trial to determine whether a second cycle of HDM/SCT could induce HCR in patients in whom the plasma cell dyscrasia persisted following initial treatment with HDM/SCT. Sixty-two patients were enrolled. Nine patients (15%) were removed from the protocol. Of the 53 patients continuing in this study, four died within 100 days of treatment (8%), and 27 (55%) achieved an HCR at 6 months after the first cycle of HDM/SCT. Of the 22 patients who did not achieve an HCR after initial treatment, 17 received a second HDM/SCT, 1 died within 100 days of treatment (6%), while 5 (31%) achieved an HCR. Thus, the HCR rate was 67% (32/48) for surviving patients on study, 60% (32/53) for all patients who received initial cycle of HDM/SCT, and 56% (35/62) by intention-to-treat. The median survival for all patients enrolled on the trial has not yet been reached. Thus, tandem cycles of HDM/SCT can increase the proportion of patients who achieve an HCR.     

Successful treatment of AL amyloidosis with high-dose melphalan and autologous stem cell transplantation in patients over age 65

Recently, protocols using high-dose melphalan chemotherapy and autologous peripheral blood stem cell transplantation (HDM/SCT) have been developed for the treatment of patients with immunoglobulin light chain (AL) amyloidosis. Although peritransplantation mortality is greater than for other hematologic diseases, treatment leads to durable hematologic complete responses, improvements in organ function and quality of life, and extended survival in a substantial proportion of patients. To determine whether this treatment can be applied to older patients, we have analyzed HDM/SCT treatment outcomes for 65 patients (aged 65 years or older) with AL amyloidosis compared with outcomes for 280 younger patients. For patients over age 65 years who meet the same eligibility criteria as younger patients, toxicity, hematologic remission rate, and survival were not significantly different from those observed in younger patients, indicating that older patients should not be excluded a priori from consideration for HDM/SCT treatment.     

Clinical analysis of autologous stem cell transplantation for nine cases of cardiac amyloidosis

Long-term survival remains poor for patients with cardiac amyloidosis. High-dose melphalan (MEL) with stem cell transplantation (HDM/SCT) is an effective treatment for AL amyloidosis, but patients with cardiac involvement are ineligible because of high therapy-related mortality. Here we report detailed HDM/SCT outcomes of 9 patients with cardiac failure. Their median age was 56 years (range, 45～66). After a median follow-up of 15 months (range 9～32), three died of multiorgan failure within the early phase after HDM/SCT, and the other six including poor risk patients are alive at present. Their symptoms of cardiac decompensation have improved. Decreases in interventricular septum thickness were confirmed in 4 patients 6～12 months after HDM/SCT by echocardiography. One-year overall survival rate was 67%, longer than previously reported rates. HDM/SCT may lead to improvements in quality of life and extended survival in cardiac amyloidosis patients. Meanwhile, the median dosage of MEL in our procedure was 103 mg/m(2) (range 68～180), less than the recommended dose, and patients were maintained on miscellaneous therapies. Further studies are required to clarify an effective MEL dose and to refine selection criteria for patients undergoing HDM/SCT.     

Long-term outcome of patients with AL amyloidosis treated with high-dose melphalan and stem-cell transplantation

Long-term survival and outcome were determined for 80 patients with immunoglobulin light chain (AL) amyloidosis treated with high-dose melphalan and stem cell transplantation (HDM/SCT) more than 10 years ago. Seventeen (21%) patients died within the first year of treatment, of treatment-related complications (14%) or progressive disease (8%). Of the 63 surviving evaluable patients at one year, 32 (51%) achieved a complete hematologic response (CR). For all 80 patients, the median survival was 57 months (4.75 yrs). The median survival exceeds 10 years for patients achieving a CR after HDM/SCT, compared with 50 months for those not achieving a CR (P < .001). In conclusion, HDM/SCT leads to durable remissions and prolonged survival, particularly for those patients who achieve a hematologic CR.     

A second course of high-dose melphalan and auto-SCT for the treatment of relapsed AL amyloidosis

High-dose melphalan and auto-SCT (HDM/SCT) induces hematological complete responses (HCRs) in 40% of patients with immunoglobulin light chain (AL) amyloidosis. However, relapses occur in 8% of patients who initially achieve HCR. We conducted a study to explore the feasibility and efficacy of a second HDM/SCT in this setting. Eleven patients were enrolled. Five patients underwent repeat stem cell mobilization with G-CSF; the others had stem cells cryopreserved from the first mobilization. Six patients received 200?mg/m(2) HDM; five patients received modified HDM at 140?mg/m(2). Engraftment occurred at a median of 10 days for neutrophils and 12 days for platelets. There was no treatment-related mortality or death within the first year, but significant grade III/IV non-hematological toxicities occurred. In all, 4 of 11 patients (36%) achieved HCR at 1 year. Two of these patients are in continuous remission at 3 and 6 years; the other two relapsed at 2 and 3 years. Of the four patients who achieved partial hematological response at 1 year, three have relapsed at a median of 3 years. Three patients died of progressive disease at 1-2 years. In conclusion, one-third of patients with AL amyloidosis who relapse after HDM/SCT can achieve HCR with a second SCT.     

A longitudinal evaluation of health‐related quality of life in patients with AL amyloidosis: associations with health outcomes over time

Light chain (AL) amyloidosis is a rare disease associated with significant, irreversible organ dysfunction and high case fatality. An observational study was conducted to assess health‐related quality of life (HRQoL) in patients treated for AL amyloidosis between 1994 and 2014 with both high dose melphalan and stem cell transplantation (HDM/SCT) or non‐SCT chemotherapy regimens. The SF‐36v1^® Health Survey (SF‐36) was administered to assess HRQoL during clinic visits. Analysis of variance was used to compare pre‐ and post‐treatment HRQoL within each treatment group to an age‐ and gender‐adjusted general population (GP) normative sample. Cox proportional hazard models were fit to examine associations between pre‐treatment levels of HRQoL and mortality within 1 and 5 years after initiating specific treatment regimens (HDM/SCT: n = 402; non‐SCT chemotherapy regimens: n = 172). Among patients who received HDM/SCT, there were significant improvements following treatment in vitality, social functioning, role‐emotional and mental health. Worse pre‐treatment SF‐36 physical component scores were associated with a greater risk of mortality in both treatment groups and follow‐up periods (P ≤ 0·005 for both). [Correction added on 20 October 2017, after first online publication: This P value has been corrected]. Using HRQoL assessments in every physician visit or treatment may provide valuable insights for treating rare conditions like AL amyloidosis.     

Pre-transplantation novel agent induction predicts progression-free survival for patients with immunoglobulin light-chain amyloidosis undergoing high-dose melphalan and autologous stem cell transplantation

Abstract

Introduction: High-dose melphalan and autologous stem cell transplantation (HDM/SCT) is an effective treatment modality for immunoglobulin light-chain (AL) amyloidosis; however, its application remains restricted to patients with good performance status and limited organ involvement. In recent years, the paradigm for AL amyloidosis has changed with the introduction of novel agents such as immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs). We hypothesized that use of novel agent induction regimens has improved outcomes for patients with AL amyloidosis undergoing HDM/SCT at our center.

Methods: All patients with AL amyloidosis, age?≥18 years who underwent HDM/SCT between 2001 and 2014 at the Fred Hutchinson Cancer Research Center and University of Washington Medical Center were included in this study. Any regimen administered within 6 months prior to HDM/SCT including an IMiD or a PI was considered a novel induction regimen. Use of induction regimen was evaluated in a Cox proportional hazard model for association with progression-free survival (PFS) and overall survival (OS).

Results: Forty-five patients with AL amyloidosis underwent HDM/SCT. The median age was 57.2 years (range 39–74.4), 15 (33.3%) were women. The median number of organs involved was 2 (range 1–5), with 20 patients having only 1 (44.4%), 10 patients having 2 (22.2%), and 15 patients (33.3%) having?≥?3 organs involved. Novel agent induction regimens were used prior to HDM/SCT in 21 patients (46.7%); these comprised PI in 13/21 (57.1%), IMiD alone in 6/21 (28.6%), PI and cyclophosphamide (CyBorD) in 3/21 (14.3%), and IMiD and PI in 3/21 (14.3%). Use of a novel agent induction regimen was associated with improved, but not OS. The 3-year PFS for patients who received a novel agent induction was 79%, while for those who did not was 53% (hazard ratio [HR]?=?0.317, p?=?0.048). The 3-year OS for patients who received novel agent induction regimens was 95%, while for those who did not was 71% (HR?=?0.454, p?=?0.247).

Discussion: Our data suggest that use of a novel agent induction regimen including an IMiD or PI prior to HDM/SCT for patients with AL amyloidosis could improve outcomes, with improvement in PFS. Although these results are limited by sample size and lack of randomization, these results support possible further investigation of novel agent induction regimens in the context of a prospective clinical trial.     

High-dose melphalan with autologous stem cell transplantation after VAD induction chemotherapy for treatment of amyloid light chain amyloidosis: a single centre prospective phase II study

Amyloid light chain (AL) amyloidosis is the result of a clonal plasma cell expansion, in which monoclonal light chains transform to amyloid deposit in various tissues and can lead to organ dysfunction and organ failure. The median survival of patients with AL amyloidosis without therapy is 10-14 months. With high-dose melphalan (HDM) and autologous stem cell transplantation (ASCT), haematological and clinical remission rates of up to 50% of treated patients have been reported from phase II studies. HDM followed by ASCT appears to prolong survival in patients, if haematological remission can be reached. In this phase II study, we evaluated vincristine, adriamycin and dexamethasone (VAD) as induction chemotherapy prior to stem cell mobilization and HDM with ASCT. The regimen was, in general, feasible in patients with AL amyloidosis, but VAD chemotherapy had a considerable World Health Organization (WHO) grade III-IV toxicity (25%) and mortality (7%) rate. VAD pretreatment did not interfere with stem cell mobilization and HDM with ASCT was possible in 86% of patients. The overall treatment efficacy was comparable with reported results of HDM and ASCT without preceding chemotherapy. We could not show an additional benefit of VAD induction in terms of increasing haematological response rate; however the 13% mortality rate after HDM and ASCT in our series was lower than the previous report.     

Spontaneous rupture of the spleen as immediate complication in autologous transplantation for primary systemic amyloidosis

Although splenic rupture is a recognized complication of primary amyloidosis, very few cases have been reported in the context of stem cell transplantation. A patient with systemic primary amyloidosis with renal and cardiac involvement and factor X deficiency, who developed a splenic rupture 24 h after the peripheral blood stem cells infusion during autologous transplantation, is described. This complication has been reported during stem cell mobilization and after post-transplant hematopoietic recovery, but we have not found a previous report of splenic rupture in the immediate postinfusion period. This case illustrates that splenic rupture can occur at any time during the transplant procedure. Need for close monitoring, particularly in patients with factor X deficiency after receiving granulocyte colony stimulating factor, two recently recognized risk factors for splenic hemorrhage, is highlighted.     

Improvement in quality of life of patients with AL amyloidosis treated with high-dose melphalan and autologous stem cell transplantation

Treatment of AL amyloidosis patients with high-dose melphalan chemotherapy followed by autologous peripheral blood stem cell transplantation (HDM/SCT) can produce hematologic complete responses (CRs) and improvement in organ function. To determine whether these responses are accompanied by improvement in quality of life (QOL), we employed the Medical Outcomes Study (MOS) 36-item Short Form General Health Survey (SF-36) questionnaire for 544 patients evaluated between 1994 and 2002. At baseline, the scores were significantly lower on all 8 SF-36 scales compared with age-matched population norms: the composite physical component summary (PCS) for the AL patients was 34.5 versus the population norm of 46.8, and the mental component summary (MCS) was 45.0 versus the norm of 51.5. All SF-36 scores improved at 1 year, with the MCS reaching the population norm. The PCS, though improved, was still lower than normal but was greater in the subgroup of patients who achieved a hematologic CR; the PCS normalized at 2 years in these patients. Thus, treatment of AL amyloidosis patients with HDM/SCT produces measurable and sustained improvements in quality of life, particularly in those patients who achieve hematologic CR.     

Cardiac Amyloidosis: Evolving Approach to Diagnosis and Management

The systemic amyloidoses are a group of heterogeneous disorders characterized by extracellular deposition of misfolded fibrillar protein that results in organ dysfunction. Involvement of the heart (cardiac amyloidosis) is manifest by increased cardiac wall thickness and impairment of myocardial diastolic and systolic properties, changes that result in heart failure, dysrhythmia, and death. Amyloidosis is classified by precursor protein, with light-chain (AL) and transthyretin (TTR) disease being most common in the United States. TTR amyloid can result from misfolding of variant TTR, a genetically inherited disease, or wild-type TTR, an acquired form of disease (termed senile systemic amyloidosis). In recent years, advances in the diagnosis and treatment of cardiac amyloidosis include identification and validation of disease biomarkers, new imaging techniques, and consensus treatment guidelines. Elevations of B-type natriuretic peptide and cardiac troponins can identify cardiac amyloidosis with a high degree of precision and confer important prognostic information. Non-invasive cardiac imaging techniques, such as cardiac magnetic resonance imaging and echocardiography with strain quantification, afford the ability to diagnose cardiac amyloidosis most often without the need for a confirmatory heart biopsy. Treatment of heart failure resulting from cardiac amyloidosis differs in many respects from most other etiologies of cardiomyopathy. The mainstay of treatment involves volume control with diuretics, low dose β-adrenergic antagonists or amiodarone for dysrhythmia, and warfarin to prevent thromboembolism. Although widely held to have a dismal prognosis, modern treatments such as high-dose melphalan with stem cell transplantation (HDM/SCT) for AL disease achieve a complete hematologic response in nearly half of eligible patients and yield long-term survival. For patients with advanced AL cardiac amyloidosis, cardiac transplantation followed by HDM/SCT is also an option that has proven highly effective. For familial amyloid derived from variant TTR, liver transplantation is the one validated treatment; however, small molecule therapeutic agents now in clinical trials appear capable of slowing or halting TTR amyloid deposition.     

Outcome of AL amyloidosis after high-dose melphalan and autologous stem cell transplantation: long-term results in a series of 421 patients

Previous studies have suggested that, in patients with AL amyloidosis treated with high-dose melphalan and autologous stem-cell transplantation (HDM/SCT), the greatest benefit is seen in those patients achieving a hematologic complete response (CR). We analyzed a series of 421 consecutive patients treated with HDM/SCT at a single referral center and compared outcomes for patients with and without CR. Treatment-related mortality was 11.4% overall (5.6% in the last 5 years). By intention-to-treat analysis, the CR rate was 34% and the median event-free survival (EFS) and overall survival (OS) were 2.6 and 6.3 years, respectively. Eighty-one patients died within the first year after HDM/SCT and were not evaluable for hematologic and organ response. Of 340 evaluable patients, 43% achieved CR and 78% of them experienced an organ response. For CR patients, median EFS and OS were 8.3 and 13.2 years, respectively. Among the 195 patients who did not obtain CR, 52% achieved an organ response, and their median EFS and OS were 2 and 5.9 years, respectively. Thus, treatment of selected AL patients with HDM/SCT resulted in a high organ response rate and long OS, even for those patients who did not achieve CR.     

Serum free light-chain responses after high-dose intravenous melphalan and autologous stem cell transplantation for AL (primary) amyloidosis

Serum free light-chain (FLC) concentrations were measured by a sensitive nephelometric immunoassay in 66 patients with AL amyloidosis before and after treatment with high-dose melphalan and autologous stem cell transplantation (HDM/SCT). At 1 year after HDM/SCT, 27 patients (41%) achieved a complete hematologic response (CR), that is, disappearance of the monoclonal gammopathy previously evident by immunofixation electrophoresis (IFE) in serum and urine and of plasma cell clonality in the bone marrow. Abnormally elevated FLC levels became normal in 27 patients (41%), and decreased by >90% in 37 (56%). Average improvements in FLC were 94% for patients who achieved a CR and 72% for those who did not (P=0.0001). However, a reduction in FLC of >90% was associated with a similar high likelihood of clinical improvement and prolonged survival, whether or not patients achieved a CR. While CR, as defined by standard criteria, is a more stringent indicator of hematologic response than are decreases in abnormally elevated FLC levels per se, these measures of hematologic response are complementary, and decreases in FLC are more readily detected early after treatment than are the changes in IFE and marrow studies required to determine CR.     

Clinical presentation and treatment responses in IgM-related AL amyloidosis

Amyloid light-chain (AL) amyloidosis is a multi-organ disease due to deposition of misfolded monoclonal immunoglobulin light chains. IgM AL amyloidosis is a rare variant, about 6% of AL amyloidosis cases, and more data are needed for treatment guidance. In IgM AL amyloidosis, the clonal cell of origin may be a plasma or lymphoplasmacytic cell, and treatments targeting each are employed. We describe presenting clinical and laboratory features of 95 patients with IgM AL amyloidosis treated at Boston University Amyloidosis Center from 1996 to 2012. The median diagnosis age was 66 years (range: 38–89) with 56% males. Organ involvement rates were: kidney (51%); heart (40%); lymph nodes (25%) and gastrointestinal tract (17%). Treatment responses were analyzed for 46 patients seen after 2003. Five treatment regimens were assigned by bone marrow pathology and patient-specific factors. Overall hematologic response rates and very good partial or complete hematologic response rates, respectively, were: high-dose melphalan/stem cell transplant (HDM/SCT) 100%;80%, Bortezomib 82%;27%, Rituximab 80%;27%, immunomodulatory agents (IMids) 75%;0%, and standard dose alkylating agents (Melphalan or cyclophosphamide) 63%;19%. Overall, 5-year survival rates were significantly higher in patients with a hematological response: 79.2?±?8.5% versus 41?±?14.9% in non-responders, which is more favorable than typically expected in AL amyloidosis.     

Outcome of autologous stem cell transplantation for AL amyloidosis in the UK

High-dose chemotherapy with autologous stem cell transplantation (SCT) is widely used as a treatment for systemic AL amyloidosis, but its efficacy has not been proved and it has substantial toxicity in this setting. We report here the outcome of 92 patients evaluated at the UK National Amyloidosis Centre who underwent SCT for AL amyloidosis between 1994 and 2004 in various British centres. Median age was 53 years and median of two organs were affected by amyloidosis. All-cause day 100 mortality [treatment-related mortality (TRM)] was 23% for the entire cohort, although this was substantially greater for patients treated from 1994 to 1998 (15/47, 32%) than subsequently (6/45, 13%). Independent factors significantly associated with TRM on multivariate analysis were: number of affected organs, performance status, serum albumin and age. Response of the underlying clonal disease, defined by > or = 50% reduction in the aberrant serum-free light chain concentration, occurred in 83% of evaluable patients. Overall median survival was 5.3 years, and was 8.5 years among patients who survived beyond day 100. Despite recent refinements in patient selection, TRM remains substantial during SCT for systemic AL amyloidosis, and its place in the therapeutic armamentarium for this disease needs to be defined in randomised controlled clinical studies.     

Sequential heart and autologous stem cell transplantation for systemic AL amyloidosis

Extensive cardiac amyloid deposition in systemic AL amyloidosis is associated with a grave prognosis. Heart transplantation is rarely performed because of the systemic and progressive nature of the disease. Patients with severe cardiac amyloid infiltration are ineligible for the preferred treatment of melphalan chemotherapy with stem cell transplantation (SCT) rescue because of the high risk for treatment-related mortality. Heart transplantation followed by SCT was performed in 5 patients with AL amyloidosis and predominant cardiomyopathy. Patients were followed up for a median of 95 months (range, 37-118 months) from diagnosis. At censor, 3 of 5 patients were well without evidence of intracardiac or extracardiac amyloid accumulation, and median overall survival by Kaplan-Meier estimate was not reached. Two patients died of progressive amyloidosis 33 and 90 months after heart transplantation after relapse of their underlying plasma cell dyscrasia. Heart transplantation followed by SCT is feasible in selected patients with cardiac AL amyloidosis and may confer substantial survival benefit.     

Association of acquired von Willebrand syndrome with AL amyloidosis

Acquired loss of functional von Willebrand factor (VWF) has been termed the acquired von Willebrand syndrome (AVWS). AVWS is a rare adult-onset bleeding diathesis that is clinically similar to congenital von Willebrand disease (VWD), and occurs with a variety of autoimmune, lymphoproliferative, or myeloproliferative disorders. We have identified four patients with AVWS in association with immunoglobulin light chain (AL) amyloidosis. These patients, lacking any pre-existing or family history of abnormal bleeding, developed cutaneous, mucosal, or gastrointestinal bleeding in the course of their disease without deficiency of clotting factor X or other factors; the activated partial thromboplastin time (aPTT) was prolonged in three out of the four cases. Despite normal VWF antigen levels, VWF ristocetin cofactor activity (VWF:RCo) was low. Electrophoresis patterns of high molecular weight (HMW) VWF multimers were abnormal in two of the four cases. Two of the patients were treated with high-dose intravenous melphalan followed by autologous stem cell transplantation (HDM/SCT) and achieved hematologic remission. In these two patients, the bleeding diathesis improved and the coagulation parameters normalized, confirming a causal relationship between the plasma cell dyscrasia and the AVWS. AVWS should be considered in AL amyloidosis patients with hemorrhagic diatheses and normal clotting factor levels.