Sarswat, Nitasha

Abstract In this systematic review, we aimed to assess the sensitivity of serum immunofixation (SIFE), urine immunofixation (UIFE), and serum free light chain (sFLC) in detecting plasma cell dyscrasia associated with light chain (AL) amyloidosis. We searched the literature using PubMed, Embase, and CENTRAL databases since inception through March 2024. We included studies reporting the diagnostic accuracy of immunofixation and/or sFLC in patients with AL amyloidosis. We used the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach to assess the certainty of the evidence and QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) to assess the risk of bias. After deduplication, 29 237 records were screened, and 44 studies (n = 18 071) were included. For the meta-analysis, 28 studies reported sensitivity for SIFE (n = 3390), 24 studies for UIFE (n = 2830), 19 studies for SIFE and UIFE (n = 2819), 21 studies for sFLC ratio (n = 3678), 6 studies for SIFE and sFLC ratio (n = 372), 3 studies for UIFE and sFLC ratio (n = 242), and 10 studies for all 3 tests (n = 1430). Pooled sensitivities were as follows: SIFE, 0.68 (95% confidence interval [CI], 0.62-0.73); UIFE, 0.77 (95% CI, 0.72-0.81); SIFE and UIFE, 0.89 (95% CI, 0.84-0.93); and sFLC ratio, 0.82 (95% CI, 0.78-0.86). When SIFE, UIFE, and sFLC ratio were combined, the sensitivity reached 0.99 (95% CI, 0.96-1.00). The high sensitivity of combining SIFE, UIFE, and sFLC ratio supports their use as a reliable initial testing strategy to raise suspicion for AL amyloidosis and guide decisions regarding future diagnostic modalities.

Abstract Systemic amyloidosis is a rare, multisystem disorder that is often challenging to diagnose due to vague and nonspecific symptoms that frequently overlap with other disorders. By the time patients are diagnosed, irreversible organ impairment from amyloid deposition occurrs, contributing to substantial morbidity and mortality. Although developing the American Society of Hematology (ASH) guidelines on systemic amyloidosis, we identified a critical knowledge gap in the recognition of the clinical presentation of its most common subtypes. Therefore, we conducted a scoping review of 117 studies following PRISMA-ScR (Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews) guidelines to identify clinical “red flags” for light chain (AL) and transthyretin (ATTR; wild-type [ATTRwt] and hereditary [ATTRv]) amyloidosis. Studies were identified from the comprehensive systematic review through the ASH amyloidosis diagnosis guideline panel, data mining, and gray literature review. Data were extracted and synthesized by systems to characterize the earliest and most frequently overlooked clinical red flags for the different types of amyloidosis. Shortness of breath and fatigue, the earliest symptoms of AL amyloidosis, contrast with the carpal tunnel syndrome occurring years before ATTRwt cardiac amyloidosis is diagnosed. Weight loss, unexplained abdominal pain, and early satiety were overlooked red flags for AL amyloidosis, compared to the preceding arrhythmias often missed in evaluation for ATTRwt amyloidosis. Sensory loss was the predominant neuropathic presentation for AL amyloidosis compared to the painful length-dependent neuropathy of ATTRv amyloidosis. Awareness of the early symptoms and distinct patterns across subtypes can enhance cross-specialty awareness and support earlier diagnosis and intervention of AL and ATTR amyloidosis.

Background Light chain (AL) amyloidosis is a rare disease caused by the misfolding of immunoglobulin light chains produced by a plasma cell dyscrasia. Patients can present with involvement of many organs, including the heart, kidneys, liver, nerves, and other sites, resulting in a high symptom burden. Timely and accurate diagnosis is important to prevent organ failure and improve patient survival. Objective These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients and clinicians in the timely and effective diagnosis of AL amyloidosis. Methods ASH formed a multidisciplinary guideline panel that included 22 individuals representing various medical specialties (academic and community hematology, nephrology, neurology, cardiology, internal medicine, and pathology) as well as 1 patient representative. The group was balanced to minimize potential bias from conflicts of interest. The University of Kansas Medical Center supported the guideline development process, including updating or performing systematic evidence reviews (up to 6 March 2023). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment. Results The panel agreed on 12 recommendations. Conclusions The use of serum immunofixation, urine immunofixation, and serum free light chains enhances the clinical suspicion of AL amyloidosis. The diagnosis of AL amyloidosis can be made effectively through surrogate biopsies, which require both a bone marrow biopsy and fat-pad sampling; however, target organ biopsies may be favored in certain clinical situations.

BACKGROUND: Transthyretin amyloidosis with cardiomyopathy is a progressive disease caused by the deposition of transthyretin (TTR) as amyloid in the myocardium. Current therapies may slow disease progression but do not clear existing deposits. Coramitug is a humanized monoclonal antibody that targets misfolded transthyretin, designed to promote clearance of transthyretin amyloid through antibody-mediated phagocytosis. METHODS: This phase 2, double-blind, placebo-controlled trial randomized participants with transthyretin amyloidosis with cardiomyopathy to receive infusions every 4 weeks of either coramitug at 2 dosages (10 mg/kg or 60 mg/kg) or placebo in a 1:1:1 ratio for 52 weeks. The primary end points were the change from baseline to week 52 in the 6-minute walk test and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. Safety was assessed for up to 64 weeks by assessing treatment-emergent adverse events, all-cause mortality, and number of cardiovascular events (comprising hospitalization caused by cardiovascular events or urgent heart failure visits). RESULTS: In total, 104 participants (median age, 77 years; 93% men; 84% New York Heart Association class II; 13% with variant transthyretin amyloidosis with cardiomyopathy) were randomized and dosed: 34 to 10 mg/kg of coramitug, 35 to 60 mg/kg of coramitug, and 35 to placebo. Median NT-proBNP was 1985 pg/mL (interquartile range, 1224, 3406). In total, 90% of participants were receiving disease-modifying therapy; 84% were treated with tafamidis and 7 (6.7%) with transthyretin silencers (patisiran, n=4; vutrisiran, n=3). From baseline to week 52, 60 mg/kg of coramitug significantly reduced NT-proBNP levels compared with placebo (–48% [95% CI, –65% to –22%]; P =0.0017). The change in 6-minute walk test from baseline to week 52 was not statistically different from placebo with either dose. Coramitug (60 mg/kg) was associated with improved functional echocardiographic parameters and was well tolerated. CONCLUSIONS: This phase 2 trial showed that coramitug, an antibody targeting misfolded transthyretin in transthyretin amyloidosis with cardiomyopathy, was well tolerated and, at a dose of 60 mg/kg, resulted in a statistically significant reduction in NT-proBNP, a validated marker of disease progression, with no statistically significant effect on 6-minute walk test within 52 weeks. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT05442047.

BACKGROUND: In the phase 3 randomized controlled study ATTRibute-CM (Efficacy and Safety of AG10 in Subjects With Transthyretin Amyloid Cardiomyopathy), acoramidis, a transthyretin stabilizer, demonstrated significant efficacy on the primary end point. Participants with transthyretin amyloid cardiomyopathy who completed ATTRibute-CM were invited to enroll in an open-label extension study (OLE). We report the efficacy and safety data of acoramidis in participants who completed ATTRibute-CM and enrolled in the ongoing OLE. METHODS: Participants who previously received acoramidis through month 30 in ATTRibute-CM continued to receive it (continuous acoramidis), and those who received placebo through month 30 were switched to acoramidis (placebo to acoramidis). Participants who received concomitant tafamidis in ATTRibute-CM were required to discontinue it to be eligible to enroll in the OLE. Clinical efficacy outcomes analyzed through month 42 included time to event for all-cause mortality (ACM) or first cardiovascular-related hospitalization (CVH), ACM alone, first CVH alone, ACM or recurrent CVH, change from baseline in NT-proBNP (N-terminal pro-B-type natriuretic peptide), 6-minute walk distance, serum transthyretin, and Kansas City Cardiomyopathy Questionnaire Overall Summary score. Safety outcomes were analyzed through month 42. RESULTS: Overall, 438 of 632 participants in ATTRibute-CM completed treatment, and 389 enrolled in the ongoing OLE (263 continuous acoramidis and 126 placebo to acoramidis). The hazard ratio for ACM or first CVH was 0.57 (95% CI, 0.46–0.72) at month 42 based on a stratified Cox proportional hazards model ( P <0.0001) favoring continuous acoramidis. Similar analyses were performed on ACM alone and first CVH alone, with hazard ratios of 0.64 (95% CI, 0.47–0.88) and 0.53 (95% CI, 0.41–0.69), respectively, at month 42. Treatment effects for NT-proBNP and 6-minute walk distance also favored continuous acoramidis. On initiation of open-label acoramidis in the placebo-to-acoramidis arm, there was a prompt increase in serum transthyretin. Quality of life assessed by Kansas City Cardiomyopathy Questionnaire Overall Summary score was well preserved in continuous-acoramidis participants compared with the placebo-to-acoramidis participants. No new clinically important safety issues were identified in this long-term evaluation. CONCLUSIONS: Early initiation and continuous use of acoramidis in the ATTRibute-CM study through month 42 of the ongoing OLE study were associated with sustained clinical benefits in a contemporary transthyretin amyloid cardiomyopathy cohort, with no clinically important safety issues newly identified. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT04988386.