Thirusha Lane

Nonbiopsy Diagnosis of Cardiac Transthyretin Amyloidosis

Background— Cardiac transthyretin (ATTR) amyloidosis is a progressive and fatal cardiomyopathy for which several promising therapies are in development. The diagnosis is frequently delayed or missed because of the limited specificity of echocardiography and the traditional requirement for histological confirmation. It has long been recognized that technetium-labeled bone scintigraphy tracers can localize to myocardial amyloid deposits, and use of this imaging modality for the diagnosis of cardiac ATTR amyloidosis has lately been revisited. We conducted a multicenter study to ascertain the diagnostic value of bone scintigraphy in this disease. Methods and Results— Results of bone scintigraphy and biochemical investigations were analyzed from 1217 patients with suspected cardiac amyloidosis referred for evaluation in specialist centers. Of 857 patients with histologically proven amyloid (374 with endomyocardial biopsies) and 360 patients subsequently confirmed to have nonamyloid cardiomyopathies, myocardial radiotracer uptake on bone scintigraphy was >99% sensitive and 86% specific for cardiac ATTR amyloid, with false positives almost exclusively from uptake in patients with cardiac AL amyloidosis. Importantly, the combined findings of grade 2 or 3 myocardial radiotracer uptake on bone scintigraphy and the absence of a monoclonal protein in serum or urine had a specificity and positive predictive value for cardiac ATTR amyloidosis of 100% (positive predictive value confidence interval, 98.0–100). Conclusions— Bone scintigraphy enables the diagnosis of cardiac ATTR amyloidosis to be made reliably without the need for histology in patients who do not have a monoclonal gammopathy. We propose noninvasive diagnostic criteria for cardiac ATTR amyloidosis that are applicable to the majority of patients with this disease.

Cyclophosphamide, bortezomib, and dexamethasone therapy in AL amyloidosis is associated with high clonal response rates and prolonged progression-free survival

Bortezomib has shown great promise in the treatment of amyloid light-chain (AL) amyloidosis. We present our experience of 43 patients with AL amyloidosis who received cyclophosphamide, bortezomib, and dexamethasone (CVD) upfront or at relapse. Of these, 74% had cardiac involvement and 46% were Mayo Cardiac Stage III. The overall hematologic response rate was 81.4%, including complete response (CR) in 41.9% and very good partial response with >90% decrease in difference between involved/uninvolved light chain (VGPR-dFLC) in 51.4%. Patients treated upfront had higher rates of CR (65.0%) and VGPR-dFLC (66.7%). The estimated 2-year progression-free survival was 66.5% for patients treated upfront and 41.4% for relapsed patients. Those attaining a CR or VGPR-dFLC had a significantly better progression-free survival (P=.002 and P=.026, respectively). The estimated 2-year overall survival was 97.7% (94.4% in Mayo Stage III patients). CVD is a highly effective regimen producing durable responses in AL amyloidosis; the deep clonal responses may overcome poor prognosis in advanced-stage disease.

Therapeutic Clearance of Amyloid by Antibodies to Serum Amyloid P Component

BACKGROUND The amyloid fibril deposits that cause systemic amyloidosis always contain the nonfibrillar normal plasma protein, serum amyloid P component (SAP). The drug (R)-1-[6-[(R)-2-carboxy-pyrrolidin-1-yl]-6-oxo-hexanoyl]pyrrolidine-2-carboxylic acid (CPHPC) efficiently depletes SAP from the plasma but leaves some SAP in amyloid deposits that can be specifically targeted by therapeutic IgG anti-SAP antibodies. In murine amyloid A type amyloidosis, the binding of these antibodies to the residual SAP in amyloid deposits activates complement and triggers the rapid clearance of amyloid by macrophage-derived multinucleated giant cells. METHODS We conducted an open-label, single-dose-escalation, phase 1 trial involving 15 patients with systemic amyloidosis. After first using CPHPC to deplete circulating SAP, we infused a fully humanized monoclonal IgG1 anti-SAP antibody. Patients with clinical evidence of cardiac involvement were not included for safety reasons. Organ function, inflammatory markers, and amyloid load were monitored. RESULTS There were no serious adverse events. Infusion reactions occurred in some of the initial recipients of larger doses of antibody; reactions were reduced by slowing the infusion rate for later patients. At 6 weeks, patients who had received a sufficient dose of antibody in relation to their amyloid load had decreased liver stiffness, as measured with the use of transient elastography. These patients also had improvements in liver function in association with a substantial reduction in hepatic amyloid load, as shown by means of SAP scintigraphy and measurement of extracellular volume by magnetic resonance imaging. A reduction in kidney amyloid load and shrinkage of an amyloid-laden lymph node were also observed. CONCLUSIONS Treatment with CPHPC followed by an anti-SAP antibody safely triggered clearance of amyloid deposits from the liver and some other tissues. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01777243.).

A European collaborative study of treatment outcomes in 346 patients with cardiac stage III AL amyloidosis.

Treatment outcomes of patients with cardiac stage III light chain (AL) amyloidosis remain poorly studied. Such cases have been excluded from most clinical studies due to perceived dismal prognosis. We report treatment outcomes of 346 patients with stage III AL amyloidosis from the United Kingdom, Italy, Germany, and Greece. Median overall survival (OS) was 7 months with OS at 3, 6, 12, and 24 months of 73%, 55%, 46%, and 29%, respectively; 42% died before first response evaluation. On an intention-to-treat basis, the overall hematologic response rate was 33%, including a complete response rate of 12%. OS rates at 12 and 24 months, respectively, for 201 response evaluable patients were 88% and 85% for complete responders, 74% and 53% for partial responders, and 39% and 22% for nonresponders. Forty-five percent of responders achieved an organ response. Amino-terminal fragment of brain-type natriuretic peptide (NT-proBNP) >8500 ng/L and systolic blood pressure (SBP) <100 mm Hg were the only factors that independently impacted OS and identified an especially poor prognosis subgroup of patients with a median OS of only 3 months. Outcome and organ function of stage III AL amyloidosis without very elevated NT-proBNP and low SBP is improved by a very good hematologic response to chemotherapy.

Utility and limitations of 3,3-diphosphono-1, 2-propanodicarboxylic acid scintigraphy in systemic amyloidosis

AIMS Technetium-99m-labelled 3,3-diphosphono-1,2-propanodicarboxylic acid ((99m)Tc-DPD) is a sensitive method for imaging cardiac transthyretin (ATTR) amyloid. We report utility and limitations of (99m)Tc-DPD scintigraphy in 321 patients with suspected cardiac amyloidosis. METHODS AND RESULTS The cohort included wild-type ATTR (ATTRwt) amyloidosis in 94 (29%), ATTR-Val122Ile amyloidosis in 38 (12%), hereditary ATTR (ATTRmt) amyloidosis in 46 (14%), primary light-chain (AL) amyloidosis in 44 (14%), secondary (AA) amyloidosis in three (1%), other hereditary amyloidosis types in nine (3%), undetermined types in two (0.5%), and 85 (26.5%) patients in whom systemic amyloidosis was ultimately excluded. All 158 patients with ATTR amyloidosis with clinical cardiac involvement had cardiac (99m)Tc-DPD uptake, with median Grade 2 intensity. Thirteen further ATTR amyloidosis patients without clinical evidence of cardiac involvement also demonstrated (99m)Tc-DPD cardiac uptake. Eighteen of 35 (51%) AL patients with cardiac involvement had (99m)Tc-DPD cardiac uptake (median Grade 1 intensity). SPECT imaging indicates that the apparent reciprocal reduction in bone uptake is due to masking of bone uptake by extensive soft-tissue uptake in ATTR amyloidosis, especially ATTRwt, and ATTR-Val122Ile types. CONCLUSION (99m)Tc-DPD scintigraphy is a highly sensitive technique for imaging cardiac ATTR amyloidosis and is an important investigation in the diagnostic pathway of patients with cardiac amyloidosis. It is not specific for ATTR in isolation but must be interpreted in a broad clinical context to avoid dangerous diagnostic errors. Diffuse skeletal muscle uptake identifies muscle as a hitherto unrecognized site that merits investigation as a target organ in ATTR amyloidosis.

Differential Myocyte Responses in Patients with Cardiac Transthyretin Amyloidosis and Light-Chain Amyloidosis: A Cardiac MR Imaging Study

PURPOSE To investigate cardiac magnetic resonance (MR) imaging measurements of extracellular volume (ECV) and total cell volume in immunoglobulin light-chain amyloidosis (AL) and transthyretin amyloidosis (ATTR) in order to evaluate the amyloid and myocyte volumes. MATERIALS AND METHODS All ethics were approved, and participants provided written informed consent. Of the 257 subjects who were recruited, 92 had AL (mean age, 62 years ± 10), 44 had mutant ATTR (mean age, 68 years ± 10), and 66 had wild-type ATTR (mean age, 75 years ± 7). In addition, eight healthy subjects with ATTR mutations (mean age, 47 years ± 6) and 47 healthy volunteers (mean age, 45 years ± 15) participated. All participants underwent equilibrium contrast material-enhanced cardiac MR imaging. ECV and total cell volume were measured in the heart. T test, χ(2), and one-way analysis of variance with posthoc Bonferroni correction were used. RESULTS Both the left ventricular indexed mass and ECV were elevated in patients with amyloidosis. For left ventricular indexed mass, mean AL was 107 g/m(2) ± 30; mean mutant ATTR was 137 g/m(2) ± 29; and mean wild-type ATTR was 133 g/m(2) ± 27 versus 65 g/m(2) ± 15 in healthy subjects (P < .0001 for all measures). For ECV, mean AL was 0.54 ± 0.07, mean mutant ATTR was 0.60 ± 0.07, and mean wild-type ATTR was 0.57 ± 0.06 versus 0.27 ± 0.03 in healthy subjects (P < .0001 for all measures). Patients with ATTR had a higher total cell volume than did healthy subjects (mean, 53 mL/m(2) ± 12 vs 45 mL/m(2) ± 11; P = .001), but in patients with AL, total cell volume was normal (mean, 47 mL/m(2) ± 17 vs 45 mL/m(2) ± 11; P > .99). The result is that, in patients with AL, all of the increase in left ventricular indexed mass is extracellular volume, whereas in patients with ATTR, the increase is extracellular, with an additional 18% increase in the intracellular space. CONCLUSION Quantification of ECV measures cardiac amyloid deposition in both types of amyloidosis and shows that amyloid deposition is more extensive in patients with ATTR than in those with AL; however, ATTR is associated with higher cell volume, which suggests concomitant cell hypertrophy.

A matched comparison of cyclophosphamide, bortezomib and dexamethasone (CVD) versus risk-adapted cyclophosphamide, thalidomide and dexamethasone (CTD) in AL amyloidosis

Despite improvements in therapy amyloid light-chain (AL) amyloidosis, there are few studies comparing different regimens. Here we present a matched comparison with 69 patients in each cohort examining upfront therapy with cyclophosphamide, bortezomib and dexamethasone (CVD) vs cyclophosphamide, thalidomide and dexamethasone (CTD). On an intention-to-treat basis, the overall response rates were 71.0% vs 79.7% in the CVD and CTD arms, respectively, (P=0.32). A higher complete response (CR) rate was observed in the CVD arm (40.5%) vs CTD (24.6%), P=0.046. One-year overall survival (OS) was 65.2% and 66.7% for CVD and CTD, respectively (P=0.87). The median progression-free survival (PFS) was 28.0 and 14.0 m for CVD and CTD, respectively (P=0.039). In a landmark analysis assessing outcomes performed at 6 months, the CR rate with CVD was 59.6% vs 34.0% for CTD (P=0.03). The 1-year OS was 96% with CVD and 92% with CTD (P=0.40). The median PFS with CVD was not reached and was 19.2 m with CTD, P=0.028). In summary, both regimens are unable to overcome the high rate of early deaths in AL amyloidosis. However, CVD correlates with improved depth of response and superior PFS supporting its use in the frontline setting. Further optimisation and better supportive-care strategies are required to increase the proportion of patients fully benefiting from therapy.

Infusion of pharmaceutical-grade natural human C-reactive protein is not proinflammatory in healthy adult human volunteers.

Rationale: Baseline circulating concentrations of C-reactive protein (CRP) are significantly associated with cardiovascular disease risk in general populations. This modest association has been inappropriately conflated with causality, and it has been claimed that CRP is proatherogenic. Most of the known causative factors for atherosclerosis stimulate increased CRP production, but comprehensive genetic epidemiology studies provide no support for a pathogenic role of CRP. The reported proinflammatory effects of human CRP preparations on healthy cells in vitro and in healthy animals in vivo have all been produced by poorly characterized CRP preparations, demonstrably caused by impurities, or elicited by CRP made in recombinant Escherichia coli not by humans. None of the in vitro or animal findings have been reproduced with pure natural human CRP. Nevertheless, the strong proinflammatory effects of infusing recombinant bacterial CRP into humans have still been inappropriately ascribed to CRP. Objective: To investigate the effects of infusion into healthy adult human volunteers of pure natural human CRP. Methods and Results: Comprehensively characterized, pharmaceutical-grade, endotoxin-free, purified CRP, prepared to GMP standard from pooled normal human donor plasma was infused as an intravenous bolus in 7 healthy adult human volunteers at ⩽2 mg/kg to provide circulating CRP concentrations ⩽44 mg/L. No recipient showed any significant clinical, hematologic, coagulation, or biochemical changes, or any increase in proinflammatory cytokines or acute phase proteins. Conclusions: The human CRP molecule itself is not proinflammatory in healthy human adults.

Clinical characteristics in subjects with NLRP3 V198M diagnosed at a single UK center and a review of the literature.

IntroductionMutations in the NLRP3 gene are associated with the dominantly inherited cryopyrin-associated periodic syndrome (CAPS). The significance of the V198M variant is unclear; it has been reported in association with various CAPS phenotypes and as a variant of uncertain consequence. The aim of this study was to characterize the clinical phenotypes and treatments in individuals with V198M assessed in a single UK center.MethodsDNA samples from 830 subjects with fever syndromes or a family history of CAPS were screened for mutations in the NLRP3 gene with polymerase chain reaction (PCR) and sequencing. A detailed medical history was available in all cases. Inflammatory disease activity was monitored monthly with measurements of serum amyloid A protein (SAA) and C-reactive protein (CRP) in symptomatic individuals.ResultsNLRP3 V198M was identified in 19 subjects. It was found in association with CAPS in five cases, in one patient with Schnitzler syndrome, in three patients who also had a nucleotide alteration in another fever gene, and in three other patients with evidence of an autoinflammatory phenotype. Seven asymptomatic individuals were detected during screening of family members.ConclusionsThe NLRP3 V198M variant shows variable expressivity and reduced penetrance. It may be associated with classical inherited or apparently sporadic CAPS and with atypical autoinflammatory disease of varying severity, intriguingly including Schnitzler syndrome. The factors that influence the pathogenic consequences of this variant remain unknown. However, the remarkable response to interleukin 1 (IL-1) blockade in all but one individual in our series confirms that their clinical features are indeed mediated by IL-1.

AA amyloidosis complicating the hereditary periodic fever syndromes.

OBJECTIVE AA amyloidosis is a life-threatening complication of the hereditary periodic fever syndromes (HPFS), which are otherwise often compatible with normal life expectancy. This study was undertaken to determine the characteristics, presentation, natural history, and response to treatment in 46 patients who had been referred for evaluation at the UK National Amyloidosis Centre. METHODS Disease activity was monitored by serial measurement of serum amyloid A. Renal function was assessed by measurement of serum creatinine and albumin levels, the estimated glomerular filtration rate, and proteinuria from 24-hour urine collections. The amyloid load was measured by serum amyloid P scintigraphy. RESULTS Twenty-four patients had familial Mediterranean fever, 12 patients had tumor necrosis factor receptor-associated periodic syndrome, 6 patients had cryopyrin-associated periodic syndromes, and 4 patients had mevalonate kinase deficiency. The median age at onset of HPFS was 5 years; median age at presentation with AA amyloidosis was 38 years. Diagnosis of an HPFS had not been considered prior to presentation with AA amyloidosis in 23 patients (50%). Eleven patients (24%) had end-stage renal failure (ESRF) at presentation; of these, 3 had received transplants prior to referral. A further 13 patients developed ESRF over the followup period, with 10 undergoing renal transplantation. The median time to progression to ESRF from onset of AA amyloidosis was 3.3 years (interquartile range [IQR] 2-8), with a median time to transplant of 4 years (IQR 3-6). Eleven patients (24%) died. The median survival in the entire cohort was 19 years from diagnosis of AA amyloidosis. Of the 37 patients who were treated successfully, or in whom at least partial suppression of the underlying HPFS was achieved, 17 (46%) showed amyloid regression, 14 (38%) showed a stable amyloid load, and 2 (5%) showed increased amyloid deposition over the followup period. CONCLUSION AA amyloidosis remains a challenging and serious late complication of HPFS; however, outcomes are excellent when HPFS is diagnosed early enough to allow effective treatment, thus preventing or retarding further amyloid deposition and organ damage.