Hematology · Medical Literature
[Review] Systemic light chain and transthyretin amyloidosis—treatment advancements and future directions
Abstract
Once rapidly fatal, neglected, and orphan diseases without approved therapeutic options, systemic amyloidoses are now highly treatable. Basic scientific discoveries regarding the molecular mechanisms of transthyretin misfolding and aggregation have driven the development of drugs for the treatment of transthyretin (ATTR) amyloidosis, with six novel therapies approved since 2018. The combination of daratumumab, cyclophosphamide, bortezomib, and dexamethasone was approved for the treatment of light chain (AL) amyloidosis in 2021.
Clinical relevance
What are the current treatment advancements and future therapeutic directions for systemic light chain (AL) amyloidosis and transthyretin (ATTR) amyloidosis, and how have they transformed the prognosis of these formerly fatal orphan diseases? __SNAPSHOT__ {"studyDesign":"Narrative/comprehensive review article (not a primary clinical trial or systematic review with meta-analysis)","setting":"Multi-institutional; authors affiliated with Dana-Farber/Brigham and Women's Hospital and Harvard Medical School (Boston, MA), Boston University Chobanian and Avedisian School of Medicine/Boston Medical Center (Boston, MA), National Amyloidosis Centre/University College London (London, UK), Mayo Clinic Department of Cardiovascular Diseases (Rochester, MN), and University of Pavia (Italy)","sampleSize":"Not applicable (review article; no primary patient cohort enrolled)","population":"Adults with systemic AL amyloidosis or ATTR amyloidosis (hereditary/variant [ATTRv] and wild-type [ATTRwt]), encompassing presentations with cardiomyopathy, polyneuropathy, and mixed phenotypes","intervention":"Review of approved pharmacotherapies for AL amyloidosis (daratumumab-cyclophosphamide-bortezomib-dexamethasone [Dara-CyBorD] and others) and ATTR amyloidosis (TTR stabilizers: tafamidis, acoramidis; TTR gene silencers: patisiran, vutrisiran, inotersen, eplontersen); discussion of emerging therapies including bispecific T-cell engagers (AL) and CRISPR-Cas9 gene editing (ATTR)","comparator":"Not applicable (review article)","primaryOutcome":"Not applicable; review covers hematologic and organ response outcomes in AL amyloidosis and functional, survival, and quality-of-life outcomes in ATTR amyloidosis across cited trials","followUp":"Not applicable (review article); individual trials cited vary in follow-up duration","fundingSource":"Not reported in the abstract; individual author disclosures not detailed in the abstract"}
Key findings
This Lancet review synthesizes the therapeutic transformation of systemic amyloidoses from universally fatal orphan diseases into highly treatable conditions. For ATTR amyloidosis, six novel therapies have been approved since 2018, spanning two mechanistic classes: (1) TTR tetramer stabilizers — tafamidis (FDA-approved 2019 for ATTR-CM; also approved by EMA for stage 1 ATTRv-PN) and acoramidis (approved for ATTR-CM in both the US and EU); and (2) TTR gene silencers — patisiran (siRNA, IV, approved for ATTRv-PN and with cardiac data from APOLLO-B), vutrisiran (siRNA, subcutaneous every 3 months, approved for ATTRv-PN and subsequently for ATTR-CM via HELIOS-B), inotersen (antisense oligonucleotide [ASO], subcutaneous weekly, approved for ATTRv-PN), and eplontersen (second-generation ASO, subcutaneous monthly via auto-injector, approved for ATTRv-PN; CARDIO-TTRansform trial ongoing for ATTR-CM). For AL amyloidosis, the quadruplet regimen of daratumumab-cyclophosphamide-bortezomib-dexamethasone (Dara-CyBorD) received regulatory approval in 2021. Since then, highly effective immunotherapies, including bispecific T-cell engagers, have demonstrated unprecedented efficacy in clinical trials for relapsed AL amyloidosis. The accompanying Lancet editorial notes that for some amyloidosis subtypes, estimated 10-year survival has increased from approximately 5% to 20% — a magnitude cited in the editorial, not the review abstract itself, and not attributed to a specific controlled trial. No head-to-head comparative trial data, specific p-values, confidence intervals, NNTs, or absolute risk reductions are reported in the abstract of this review.
Practice implications
This review establishes that both AL and ATTR amyloidosis have undergone a paradigm shift from therapeutic nihilism to a multi-drug, mechanism-targeted treatment landscape. For ATTR-CM specifically, tafamidis, acoramidis, and vutrisiran are now all FDA- and EMA-approved, with evidence supporting survival benefit and reduction in cardiovascular hospitalizations. For ATTRv-PN, four approved agents (patisiran, vutrisiran, inotersen, eplontersen) offer varying routes and schedules; existing data suggest greatest efficacy in early-to-mid stage disease (NYHA class I–II for CM, stage 1–2 for PN). For newly diagnosed AL amyloidosis, Dara-CyBorD has become the standard-of-care backbone. Emerging therapies — bispecific T-cell engagers in relapsed/refractory AL and gene-editing strategies (CRISPR-Cas9) in ATTR — may further expand options but remain investigational. The review does not establish superiority of any approved agent over another; no head-to-head trials have been conducted, and indirect comparisons via network meta-analysis (from separately published studies) do not demonstrate statistically significant differences between TTR stabilizers and gene silencers on the primary composite endpoint of all-cause mortality and cardiovascular hospitalization. Key gaps include the lack of robust data in advanced-stage disease (NYHA III–IV, PN stage 3), underrepresentation of women, non-White patients, and younger or pediatric populations. The optimal sequencing, combination, or switching of agents is not established. Critically, only the abstract was available for this summary; the full evidence synthesis, specific drug trial data reviewed, author disclosures, and any meta-analytic results within the review could not be independently verified and may contain important additional nuance. __LIMITATIONS__ 1. Study design: This is a narrative review — not a systematic review or meta-analysis — meaning conclusions are subject to author selection bias in choosing cited studies. 2. Abstract-only availability: This summary is based solely on the published abstract; the full review's methodology, evidence grading, and conflict-of-interest disclosures were not accessible and could not be evaluated. 3. No primary data: No new patient-level data are generated; all clinical effect sizes derive from previously published trials with their own individual limitations. 4. Heterogeneity of underlying trials: Cited pivotal trials (e.g., ATTR-ACT for tafamidis, HELIOS-B for vutrisiran, ATTRIBUTE-CM for acoramidis, ANDROMEDA for Dara-CyBorD in AL) differ in patient populations, disease stage, primary endpoints, and follow-up duration, making cross-trial comparisons unreliable. 5. Population representativeness: ATTR-CM trial populations have been predominantly older White men with wild-type disease; applicability to women, non-White patients, and younger individuals with hereditary variants is uncertain. 6. Surrogate vs. clinical endpoints: Some ATTR-PN trials rely on validated surrogate endpoints (e.g., modified NIS+7, serum TTR reduction) rather than survival; the clinical translation of these surrogates over long follow-up is incompletely characterized. 7. Funding and conflict of interest: Author affiliations include major academic amyloidosis referral centers with extensive industry relationships; disclosures in the full article were not reviewed. 8. Rapidly evolving landscape: Given the pace of approvals (six ATTR agents since 2018), portions of this review may be superseded quickly by new trial results or regulatory decisions. 9. Cost and access not addressed: The very high per-annum drug costs (exceeding $450,000–$500,000 annually for some agents) and implications for health system sustainability are not discussed in the abstract. __BOTTOM_LINE_CATEGORY__ potentially_practice_informing __BOTTOM_LINE__ Systemic AL and ATTR amyloidoses have been fundamentally transformed by targeted therapies approved since 2018–2021, with six novel ATTR-directed agents and the Dara-CyBorD regimen for AL now available; clinicians should promptly and accurately subtype amyloid to select appropriate therapy, as treatment is now highly disease-mechanism-specific. Emerging immunotherapies (bispecific T-cell engagers for AL) and gene-editing strategies (CRISPR-Cas9 for ATTR) signal further therapeutic evolution, though these remain investigational. No head-to-head trials exist to guide agent selection within approved ATTR classes; treatment decisions should be individualized based on phenotype (cardiomyopathy vs. polyneuropathy vs. mixed), disease stage, comorbidities, route of administration, and local regulatory approval.