Tafamidis built a multi-billion-dollar ATTR-CM franchise as the only stabilizer — now acoramidis competes head-on and vutrisiran has entered cardiomyopathy, while net-price pressure comes from rivalry and looming generics, not from IRA negotiation.
Transthyretin amyloidosis (ATTR) is two commercial markets in one disease. ATTR cardiomyopathy (ATTR-CM) is dominated by oral TTR-tetramer stabilizers: tafamidis (Vyndaqel/Vyndamax, Pfizer), approved May 2019 on the ATTR-ACT trial, and acoramidis (Attruby, BridgeBio), approved November 2024 on ATTRibute-CM as the first direct stabilizer competitor. ATTR polyneuropathy (ATTR-PN) is held by RNA-based TTR silencers: the siRNAs patisiran (Onpattro, IV) and vutrisiran (Amvuttra, SC) from Alnylam, and the antisense agent inotersen (Tegsedi, Ionis/AstraZeneca). Vutrisiran won an ATTR-CM indication in March 2025 on the HELIOS-B trial, opening a direct stabilizer-versus-silencer contest inside cardiomyopathy.
The commercial story is defined by two forces. First, competition arrived in ATTR-CM: after five years as the only option, tafamidis faces acoramidis, which reported a composite of all-cause mortality and cardiovascular hospitalisation of 64.5% versus 74.0% on placebo at 30 months — a clinical-differentiation argument BridgeBio is using at launch. Second, price: tafamidis carries an annual US list price near $268,000, yet, despite Medicare spend among the highest in the category, it sits outside CMS IRA drug-price negotiation, shielded by the orphan-drug exclusion that the 2025 tax-and-spending law broadened to cover multi-orphan-designation drugs. ICER's 2024 review judged the TTR stabilizers priced roughly 85–95% above a cost-effective level, and it is acoramidis's entry (launched below tafamidis) plus pending generic tafamidis that are compressing net price.
FDA-approved transthyretin amyloidosis therapies — United States, 2026
| Drug (Brand / INN) | Mechanism | Company | Indication | US Approval | Key Trial Result |
|---|---|---|---|---|---|
| Vyndaqel / Vyndamax (tafamidis) | Oral TTR-tetramer stabilizer | Pfizer | ATTR-CM | May 2019 | ATTR-ACT: all-cause mortality −29.5% at 30 months vs placebo |
| Attruby (acoramidis) | Oral TTR-tetramer stabilizer | BridgeBio | ATTR-CM | Nov 2024 | ATTRibute-CM: mortality + CV hospitalisation 64.5% vs 74.0% at 30 months |
| Amvuttra (vutrisiran) | siRNA TTR silencer (SC) | Alnylam | ATTR-CM (2025) + ATTR-PN (2022) | Jun 2022 / Mar 2025 | HELIOS-B: 28% reduction in mortality + CV events vs placebo |
| Onpattro (patisiran) | siRNA TTR silencer (IV) | Alnylam | ATTR-PN | Aug 2018 | APOLLO: mNIS+7 −34.0 vs +24.9 placebo |
| Tegsedi (inotersen) | Antisense TTR silencer (SC) | Ionis / AstraZeneca | ATTR-PN | Oct 2018 | NEURO-TTR: mNIS+7 difference −19.7 vs placebo |
Sources: FDA Drugs@FDA (approval status and dates); ATTR-ACT, NEJM 2018 (PMID 30145929); ATTRibute-CM, NEJM 2024 (PMID 38197816); APOLLO, NEJM 2018 (PMID 29972753); HELIOS-A, Amyloid 2022 (PMID 35875890); HELIOS-B, NEJM 2025 (PMID 39213194). Tafamidis list price and value-based benchmark per ICER October 2024.
What this brief answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- • Stabilizer vs silencer mechanism and the ATTR-CM vs ATTR-PN indication split • Efficacy across ATTR-ACT, ATTRibute-CM, APOLLO, HELIOS-A and HELIOS-B • Oral vs IV vs SC administration and monitoring burden by agent • How vutrisiran's 2025 ATTR-CM approval resets the stabilizer-vs-silencer contest
Delivers
- • ATTRibute-CM composite result and the clinical-differentiation argument • Two-stabilizer rebate dynamics and step-edit / therapeutic-interchange risk • Prescriber switching considerations in a chronic, high-cost oral market • Launch positioning against an entrenched five-year incumbent
Delivers
- • Why tafamidis sits outside IRA negotiation (the orphan-drug exclusion) despite high Medicare spend • Acoramidis's below-tafamidis launch and the two-stabilizer rebate dynamic • Pending generic tafamidis and its net-price implications • Part D routing for oral stabilizers vs Part B for infused/injected silencers, and the ICER 2024 value benchmark
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Commission This BriefWhat's inside
- ATTR is two markets in one disease: oral stabilizers dominate cardiomyopathy while RNA silencers hold polyneuropathy.
- Why vutrisiran's March 2025 ATTR-CM approval, on the HELIOS-B trial, opened a direct stabilizer-versus-silencer contest in cardiomyopathy.
- ATTR-ACT data show tafamidis reducing all-cause mortality by 29.5% relative to placebo at 30 months.
- Why acoramidis's ATTRibute-CM composite endpoint of 64.5% versus 74.0% at 30 months gives BridgeBio its differentiation argument.
- After five years as the only ATTR-CM stabilizer, tafamidis now faces direct competition from acoramidis, approved November 2024.
- Why acoramidis launched priced below tafamidis, setting up a two-stabilizer rebate dynamic in a chronic, high-cost oral market.
- Vutrisiran's HELIOS-B trial found a 28% reduction in mortality and cardiovascular events versus placebo, backing its 2025 ATTR-CM approval.
- Why vutrisiran is the only silencer approved in both ATTR-PN (2022) and ATTR-CM (2025), unlike patisiran and inotersen.
- Why tafamidis's ~$268,000 annual list price sits outside CMS IRA negotiation, shielded by the orphan-drug exclusion.
- ICER's October 2024 review judged the TTR stabilizer class priced roughly 85-95% above a cost-effective level.
- Why pending generic tafamidis, alongside acoramidis's below-list launch price, is compressing net pricing across the stabilizer class.
- With five FDA-approved ATTR therapies already spanning stabilizer and silencer mechanisms, next-generation approaches must differentiate against a crowded field.
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How AXLRx builds this brief
Prepared by MoatRx analysts.
Every AXLRx brief is built from primary regulatory sources (FDA Drugs@FDA, ClinicalTrials.gov), peer-reviewed literature, and live payer and HTA documentation — not secondary summaries, market-research reports, or unverified estimates. Findings are independently verified before inclusion; if a figure cannot be sourced to a live record, it does not ship.
US ATTR Amyloidosis Competitive Intelligence sources: FDA Drugs@FDA (approval status and dates), primary trial publications in the New England Journal of Medicine and Amyloid (ATTR-ACT, ATTRibute-CM, APOLLO, HELIOS-A, HELIOS-B), ClinicalTrials.gov registrations, the CMS selected-drug fact sheets confirming tafamidis's absence from IRA negotiation, and the ICER October 2024 ATTR-CM assessment.
- Tafamidis ATTR-CM mortality result verified against ATTR-ACT, NEJM 2018 (PMID 30145929); acoramidis against ATTRibute-CM, NEJM 2024 (PMID 38197816)
- Patisiran and vutrisiran results verified against APOLLO (PMID 29972753), HELIOS-A (PMID 35875890) and HELIOS-B (PMID 39213194)
- Approval status and indications, including vutrisiran's March 2025 ATTR-CM approval, verified against FDA Drugs@FDA
- Tafamidis's exclusion from CMS IRA drug-price negotiation (orphan-drug exclusion) verified against the CMS selected-drug fact sheets (IPAY 2026–2028); TTR-stabilizer cost-effectiveness verified against the ICER October 2024 ATTR-CM report
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