Martha Skinner

High-Dose Melphalan and Autologous Stem-Cell Transplantation in Patients with AL Amyloidosis: An 8-Year Study

Context AL amyloidosis responds poorly to oral chemotherapy and rarely leads to elimination of plasma cell dyscrasia. Amyloid cardiomyopathy is a particularly fatal complication of the disease. Contribution Analysis of consecutive patients with AL amyloidosis from 6 separate trials over 8 years shows that high-dose intravenous melphalan therapy combined with autologous stem-cell transplantation greatly improves duration of survival and ameliorates organ dysfunction. Implications Intravenous melphalan therapy combined with stem-cell transplantation represents a clinically significant improvement in treating AL amyloidosis and shows promise in reversing amyloid cardiomyopathy. The Editors The most common form of systemic amyloidosis in the United States is AL (or primary) amyloidosis. In this disease, amyloid fibrils are derived from monoclonal immunoglobulin light chains that are produced by an underlying clonal plasma cell dyscrasia. Although the burden of plasma cells is generally low, accumulation of amyloid deposits in vital organs leads to progressive disability and death. The median survival of untreated patients after diagnosis is 12 months and less than 5 months for those with cardiomyopathy (1-5). AL amyloidosis is reported to occur in 5 to 12 persons per million per year in the United States; however, death records and autopsy results suggest that the incidence may be higher (6, 7). Treatment with oral melphalan results in a modest increase in median survival but rarely eliminates the plasma cell dyscrasia and is not effective for rapidly progressive disease (8-10). Alternative chemotherapy regimens have not improved survival further (11-15). Promising treatment outcomes observed with high-dose intravenous melphalan and autologous stem-cell transplantation in multiple myeloma (16-19) provided a rationale for testing the hypothesis that this treatment would improve survival for patients with AL amyloidosis. Favorable responses to high-dose melphalan and stem-cell transplantation in patients with AL amyloidosis have been reported in case reports and in small series; however, treatment-related mortality was high in multicenter trials (20-28). Our initial experience with treatment in AL amyloidosis indicated that selected patients can tolerate treatment and that hematologic responses and reversal of amyloid-related organ dysfunction can be achieved (29-32). Since 1994, we have evaluated 701 patients with AL amyloidosis, 312 of whom initiated high-dose melphalan treatment and stem-cell transplantation. This longitudinal study examines survival, hematologic response, and improvement of amyloid-related organ disease in patients who were treated with high-dose melphalan and stem-cell transplantation. We contrast these data with features and survival of a simultaneous cohort of patients who were not eligible for treatment. Methods Patients Between July 1994 and June 2002, 701 consecutive patients with AL amyloidosis were evaluated and clinical data were collected with the approval of the Institutional Review Board of Boston University Medical Center. All patients had biopsy-proven amyloid disease and a documented plasma cell dyscrasia, which was diagnosed by the presence of clonal plasma cells in the bone marrow or a monoclonal gammopathy detected by immunofixation electrophoresis of serum or urine proteins (Figure 1). To exclude another type of systemic amyloidosis and a monoclonal gammopathy of unknown significance, all patients with findings compatible with familial or secondary (AA) amyloidosis were tested by DNA analysis for gene mutations in transthyretin, apolipoprotein A1, fibrinogen, and lysozyme known to be associated with amyloidosis and by immunohistochemistry of the biopsy tissue for AA amyloid fibril deposits (33). Patients with multiple myeloma (bone marrow plasmacytosis 30% or lytic bone lesions) were excluded. In patients older than 70 years of age with cardiomyopathy only, a diagnosis of senile cardiac amyloidosis (caused by wild-type transthyretin) was excluded by immunohistochemical examination of a tissue biopsy specimen using antiserum to transthyretin. All patients were evaluated for degree of organ involvement by physical examination, standardized blood tests, electrocardiography, echocardiography, chest radiography, pulmonary function tests, and a 24-hour urine collection. All patients were evaluated by a hematologist and cardiologist and, when appropriate, by nephrology, pulmonology, gastroenterology, and neurology specialists. Figure 1. Algorithm for patient selection and treatment with high-dose melphalan and stem-cell transplantation. High-Dose Melphalan and Stem-Cell Transplantation Eligibility and Protocols Patients were enrolled in several sequential institutional review boardapproved protocols during the 8-year study period. Eligibility criteria for all protocols required biopsy-proven amyloid disease; evidence of a plasma cell dyscrasia; at least 1 major organ affected by amyloid disease; and minimum measures of cardiac, pulmonary, and performance status (Figure 1). Functional measures included cardiac ejection fraction 0.4 or greater, absence of symptomatic pleural effusions, absence of heart failure or arrhythmia resistant to medical management, oxygen saturation of 95% or greater on room air, lung diffusing capacity of 50% or more of predicted, supine systolic blood pressure of 90 mm Hg or greater, and Southwest Oncology Group performance status score of 2 or less unless limited by neuropathy (on a scale of 0 to 4, reflecting percentage of the day [0%, 25%, 50%, 75%, or 100%] spent in bed or in a chair). Minor variations in eligibility requirements for age, renal function, amount of previous chemotherapy, and time from diagnosis while on some protocols are noted in the following discussion; the number of patients affected is also given. The first protocol (July 1994 to December 1995) enrolled 13 patients 60 years of age or younger with serum creatinine values of 176.8 mol/L (2.0 mg/dL) or less; these patients were treated with melphalan, 200 mg/m2 (29). Subsequent protocols had no restriction for impaired renal function. A second protocol (April 1995 to October 1996) enrolled 28 patients 70 years of age or younger and used a lower dose of melphalan, 100 mg/m2 (31). Two protocols (January 1996 to June 1998) evaluated the use of CD34+-selected stem cells in 16 patients (34). The fifth protocol (October 1996 to September 2000) randomly assigned 100 previously untreated patients to treatment with high-dose melphalan and stem-cell transplantation immediately or after 2 cycles of oral melphalan and prednisone. There was no age limit for this protocol; however, melphalan, 140 mg/m2, was given to patients who were older than 65 years of age or had a cardiac ejection fraction between 0.40 and 0.44. The sixth protocol (November 2000 to the present) has enrolled 29 patients 65 years of age or younger. On this protocol, enough stem cells are collected initially to give a second cycle of chemotherapy within the first year if a complete response has not been achieved after an initial course of melphalan at a dose of 200 mg/m2. Other patients who met eligibility criteria (August 1996 to the present) but were excluded from an active protocol because of previous treatment or time from diagnosis were treated by using the established dosing guidelines. Patients who did not meet eligibility for treatment with high-dose melphalan and stem-cell transplantation were grouped according to reasons for ineligibility and were analyzed for survival. Organ system involvement was defined by physical examination; postural blood pressure determinations; standardized serologic laboratory measurements of kidney, liver, and endocrine function; coagulation studies, including factor X levels; electrocardiography; echocardiography; chest radiography; pulmonary function tests with walking oximetry; and a 24-hour urine collection for protein excretion. Cardiac involvement was defined by septal or posterior wall thickening of 13 mm or greater on echocardiography or a clinical syndrome of congestive heart failure or cardiac arrhythmia in the absence of preexisting cardiac disease. Renal involvement was diagnosed by proteinuria of 500 mg/24 h or greater or an elevated serum creatinine concentration in the absence of other causes of renal disease. Gastrointestinal involvement was diagnosed by involuntary loss of 10% of body weight, unexplained diarrhea, hepatomegaly of 4 cm or more below the right costal margin on physical examination, or alkaline phosphatase level 2 or more times the upper limit of normal values. Peripheral neuropathy was diagnosed by symptoms and physical examination or nerve conduction studies, and autonomic neuropathy was defined by orthostatic hypotensiona decrease in systolic blood pressure of 20 mm Hg or greater with upright posture in euvolemic patients. Soft tissue involvement was diagnosed by clinical evidence of macroglossia, soft tissue or subcutaneous deposits, amyloid arthropathy, lymphadenopathy, or nail dystrophy. Coagulation factor X level was considered deficient if it was 50% or less of normal. Stem-Cell Collection and High-Dose Chemotherapy Peripheral blood stem cells were collected by leukapheresis after mobilization using granulocyte colony-stimulating factor. A minimum yield of 2.0 106 CD34+cells/kg of body weight was required to support high-dose chemotherapy. The patients age and cardiac status and the number of stem cells collected determined the melphalan dose (Figure 1). A dose of 200 mg/m2 was administered to patients who were 65 years of age or younger and who had a cardiac ejection fraction of 0.45 or greater and a stem-cell collection of at least 2.5 106 CD34+cells/kg. A dose of 140 mg/m2 was administered to patients who were older than 65 years of age, who had a cardiac ejection fraction of 0.4 to 0.44, or who had a stem-cell collection of 2.0 to 2.5 106 CD34+cells/k

Human Amyloidogenic Light Chains Directly Impair Cardiomyocyte Function Through an Increase in Cellular Oxidant Stress

Primary amyloidosis is a systemic disorder characterized by the clonal production and tissue deposition of immunoglobulin light chain (LC) proteins. Congestive heart failure remains the greatest cause of death in primary amyloidosis, due to the development of a rapidly progressive amyloid cardiomyopathy. Amyloid cardiomyopathy is largely unresponsive to current heart failure therapies, and is associated with a median survival of less than 6 months and a 5-year survival of less than 10%. The mechanisms underlying this disorder, however, remain unknown. In this report, we demonstrate that physiological levels of human amyloid LC proteins, isolated from patients with amyloid cardiomyopathy (cardiac-LC), specifically alter cellular redox state in isolated cardiomyocytes, marked by an increase in intracellular reactive oxygen species and upregulation of the redox-sensitive protein, heme oxygenase-1. In contrast, vehicle or control LC proteins isolated from patients without cardiac involvement did not alter cardiomyocyte redox status. Oxidant stress imposed by cardiac-LC proteins further resulted in direct impairment of cardiomyocyte contractility and relaxation, associated with alterations in intra-cellular calcium handling. Cardiomyocyte dysfunction induced by cardiac-LC proteins was independent of neurohormonal stimulants, vascular factors, or extracellular fibril deposition, and was prevented through treatment with a superoxide dismutase/catalase mimetic. This study suggests that cardiac dysfunction in amyloid cardiomyopathy is directly mediated by LC protein-induced cardiomyocyte oxidant stress and alterations in cellular redox status, independent of fibril deposition. Antioxidant therapies or treatment strategies aimed at eliminating circulating LC proteins may therefore be beneficial in the treatment of this fatal disease.

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

Summary: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.

Cellular Response of Cardiac Fibroblasts to Amyloidogenic Light Chains

Amyloidoses are a group of disorders characterized by abnormal folding of proteins that impair organ function. We investigated the cellular response of primary cardiac fibroblasts to amyloidogenic light chains and determined the corresponding change in proteoglycan expression and localization. The cellular response to 11 urinary immunoglobulin light chains of kappa1, lambda6, and lambda 3 subtypes was evaluated. The localization of the light chains was monitored by conjugating them to Oregon Green 488 and performing live cell confocal microscopy. Sulfation of the proteoglycans was determined after elution over Q1-columns with a single-step salt gradient (1.5 mol/L NaCl) via dimethylmethylene blue. Light chains were detected inside cells within 4 hours and demonstrated perinuclear localization. Over 80% of the cells showed intracellular localization of the amyloid light chains. The light chains induced sulfation of the secreted glycosaminoglycans, but the cell fraction possessed only minimal sulfation. Furthermore, the light chains caused a translocation of heparan sulfate proteoglycan to the nucleus. The conformation and thermal stability of light chains was altered when they were incubated in the presence of heparan sulfate and destabilization of the amyloid light chains was detected. These studies indicate that internalization of the light chains mediates the expression and localization of heparan sulfate proteoglycans.

Predictive factors for hematopoietic engraftment after autologous peripheral blood stem cell transplantation for AL amyloidosis

Summary:Treatment of patients with AL amyloidosis with high-dose melphalan and autologous peripheral blood stem cells (PBSC) produces hematologic remissions in approximately 40% of evaluable patients, accompanied by improvements in organ disease and quality of life. These patients, who frequently have amyloid deposits in bone marrow blood vessels and interstitium and impaired function of kidneys, liver, spleen, and heart, represent an unusual population for stem cell transplantation, with unique problems. To identify factors influencing engraftment rates after chemotherapy and autologous granulocyte colony-stimulating factor (G-CSF)-mobilized PBSC reinfusion, we studied a group of 225 patients. The median time to neutrophil engraftment was 10 days (range, 8–17 days). In a multivariate analysis, the factors positively affecting the rate of neutrophil engraftment were CD34+ stem cell dose, female gender, and minimal prior alkylator therapy. The median time to platelet engraftment was 13 days (range, 7–52 days). Factors positively affecting platelet engraftment, in addition to CD34+ cell dose, included preserved renal function and the absence of neutropenic fever. The conditioning dose of intravenous melphalan was not found to be an independent predictive factor for hematopoietic recovery. Thus, in this patient population, organ function and host and hematopoietic factors influence engraftment after PBSC rescue.

A rare transthyretin mutation (Asp18Glu) associated with cardiomyopathy

The identification of a rare transthyretin (TTR) gene mutation (Asp18Glu) in a middle-aged male with biopsy proven amyloid disease featuring cardiomyopathy is described. The more commonly occurring light chain amyloidosis (AL) was initially considered, but negative hematologic testing prompted screening for a pathologic TTR mutation. A differential diagnosis of familial transthyretin type amyloidosis (ATTR) was established using a combination of molecular genetic and biochemical techniques. Single-strand conformation polymorphism (SSCP) screening of exons 2, 3 and 4 of the TTR gene indicated the presence of atypical DNA. SSCP testing was performed using a new non-radioactive, silver stained minigel technique. The genetic abnormality was identified by direct DNA sequence analysis as a T to A transversion at the third base position in codon 18. This result was confirmed by restriction fragment length polymorphism (RFLP) testing. The presence of the variant protein, TTR Asp18Glu, in serum from the proband was confirmed by mass spectrometric analysis.