The ATTR-CM Market
Pfizer's incumbency, new rivals and accusations of unfair competition
Transthyretin amyloid cardiomyopathy has gone from a disease with no approved treatment to one of the most fiercely contested markets in cardiology. Pfizer's tafamidis had the field to itself from 2019 until late 2024, when BridgeBio's Attruby arrived, followed in 2025 by Alnylam's Amvuttra. Since then, critics have questioned whether rebates, misleading marketing campaigns and patent settlements are protecting the incumbent.
Questions
What is the ATTR-CM market and who competes in it?
Three approved therapies now compete — two oral stabilisers and one injected silencer — in a market serving roughly 240,000 US patients where Pfizer held an unchallenged monopoly for five years.
ATTR-CM occurs when the transthyretin protein misfolds and deposits as amyloid in the heart, causing stiffening, heart failure and death within around 2.5 years if left untreated. BridgeBio estimates there are about 240,000 US patients. Three approved treatments now compete. Pfizer's tafamidis (Vyndaqel/Vyndamax) and BridgeBio's acoramidis (Attruby) are oral "stabilisers" that prevent the protein from breaking apart; Alnylam's vutrisiran (Amvuttra) is an injected "silencer" that reduces production of the protein. Pfizer had the ATTR-CM market to itself for five years. BridgeBio won approval in November 2024 and Amvuttra, already approved for ATTR polyneuropathy, received its cardiomyopathy approval in March 2025. Other therapies, including RNAi, antisense, antibody and gene-editing candidates, are in development.
Q2How dominant is Pfizer in ATTR-CM?
Critics point not to clinical differentiation alone but to a range of commercial tactics — misleading 'first and only' claims, patent settlements to 2031, Vyndaqel's discontinuation to protect the 2035 patent, and formulary-level rebate advantages.
Although Pfizer maintains a dominant market share, critics point to a range of commercial tactics, rather than clinical differentiation alone, to explain how it has held on to it. Critics cite promotional claims they say overstate Vyndamax's position, such as describing it as the "first and only approved treatment" after competitors had launched. They also point to patent settlements that delay generic entry to 2031, the discontinuation of Vyndaqel ahead of its 2028 patent expiry, which moved patients to a formulation protected until 2035, and rebate-driven formularies that can favour incumbents with large patient bases.
Q3How are ATTR-CM drugs priced?
Attruby launched at ~$244,000 — below Vyndamax at ~$268,000 and far below Amvuttra at ~$476,000 — with analysts warning the silencer faces 'significant payer headwinds' at nearly double the stabiliser price.
All three approved drugs are expensive, but BridgeBio's Attruby has the lowest list price. BridgeBio launched Attruby at about $244,000 a year, below tafamidis at nearly $268,000 in 2024, while Alnylam priced Amvuttra for ATTR-CM at about $476,000 a year, nearly double its stabiliser rivals, prompting analysts to warn of "significant payer headwinds." BridgeBio's CEO describes Attruby as "the lowest-priced product with the best data at 30 months", and in August 2026 BridgeBio agreed with the US government to keep offering Attruby through Medicare Part D. BridgeBio's Attruby has also been shown to be the most effective: its trial showed benefits within about three months, a real-world study found a 34% lower risk of clinical worsening than with tafamidis, and it reports kidney-protection data and a 41% reduction in outpatient worsening heart failure.
Q4What have Pfizer and Alnylam been accused of?
Pfizer has been accused of 'first and only' claims after two rivals launched and an unfair Attruby comparison; Alnylam pulled a misleading TV ad in September 2025 and the FDA challenged its website survival claims in April 2026.
Both have faced accusations over how they promote their ATTR-CM drugs. Pfizer's critics say it showed a video at a medical meeting describing Vyndamax as the "first and only approved treatment" after two competitors had launched, and presented a comparison with Attruby that was not based on fair and comparable standards. Critics also point to a German court ruling, which told Pfizer to stop claiming "near-complete stabilization". Patient advocates have questioned Pfizer's "only" once-daily capsule wording. Alnylam's problems come from the FDA itself. In September 2025 the agency said an Amvuttra TV ad, showing patients whale-watching and cheering at football games, misleadingly suggested the drug would broadly improve quality of life; Alnylam pulled the ad while insisting its materials were truthful. In April 2026 the FDA sent a second letter, this time over survival claims on the Amvuttra website, discussed in the next question. Alnylam's price, nearly double its rivals', has also drawn analyst criticism.
Q5Why has the FDA challenged Alnylam's Amvuttra survival claims?
The FDA said Amvuttra's website "36% Lower Risk" and "80% Survival Rate" figures came from an open-label extension with no true control group — data "incapable of supporting the conclusions" — and yet the claims remained live weeks later.
In April 2026 the FDA sent Alnylam an untitled letter about the ATTR-CM page of the Amvuttra consumer website. The page carried the headline "Proven to help people with ATTR-CM live longer" and said the risk of death was lower over 3.5 years with Amvuttra, with graphics showing a "36% Lower Risk compared to placebo" and an "80% Survival Rate". The FDA said these created a misleading impression that Amvuttra had shown a definitive and quantified survival benefit. The problem was the data source: the 3.5-year figures came from an open-label extension in which all placebo patients had switched to the drug, leaving no true control group, so the FDA said the extension was "incapable of supporting the conclusions." As of early May 2026, the claims were still on the website. It was Alnylam's second FDA letter over Amvuttra promotion, after a September 2025 letter about a TV ad. The episode matters because there are no head-to-head trials in ATTR-CM, so cardiologists and patients rely heavily on how each company frames its own survival data.
Q6How do PBMs and rebates shape competition in ATTR-CM?
An incumbent with a large patient base can offer larger total rebates — and PBM income is often tied to list price — a dynamic the FTC's Express Scripts and Caremark settlements in insulin are now trying to dismantle by delinking fees from list prices.
ATTR-CM stabilisers are pharmacy drugs, so their placement on PBM formularies strongly influences which one patients receive. In Medicare Part D, manufacturers pay rebates to PBMs, which share them with plans, to secure formulary inclusion or preferred status, sometimes while excluding competitors. The logic critics highlight is that a dominant incumbent, such as Pfizer, can offer larger total rebates across a big patient base, and that PBM income is often tied to list price. The FTC's settlements with Express Scripts and Caremark over insulin now require them to delink PBM fees from list prices and stop discriminating against lower-cost options, reforms that could spill over into ATTR-CM.
Q7How do the tafamidis patent settlements affect the market?
April 2026 settlements with Dexcel, Hikma and Cipla delay US generic tafamidis entry from the expected 2028 to June 2031 — prolonging branded prices and drawing long-standing federal antitrust scrutiny of such "pay for delay" arrangements.
In April 2026 Pfizer settled patent litigation with generic makers Dexcel, Hikma and Cipla, pushing US generic tafamidis entry to June 1, 2031, pending other litigation. Pfizer had expected exclusivity might end in 2028. For consumers, the settlements delay the arrival of cheaper generic tafamidis, which would likely have driven down prices across the stabiliser class. Because Pfizer may benefit from delayed generics, critics argue that competition among brands alone will not bring prices down. Such settlements have long drawn scrutiny from federal regulators.
Q8Why is the ATTR-CM market growing so quickly?
Better imaging, EMR flags and AI algorithms are converting 240,000 undiagnosed patients into treated ones — Attruby reached $222.4 million in US Q2 2026 revenue, up 211% year on year, and BridgeBio calls it the fastest-growing product in the space.
Several factors are driving growth, and BridgeBio's figures show how fast the treated population is expanding. ATTR-CM was long underdiagnosed; better imaging and awareness mean patients are now diagnosed earlier than in the original tafamidis trial, and BridgeBio estimates about 240,000 US patients. BridgeBio's CEO says new patient starts are rising because EMR flags, AI algorithms and broader education prompt busy heart failure practices to test for the disease, and notes that 50% to 60% of patients also have atrial fibrillation, a large group for which it has presented supporting data. By the end of 2025, Attruby had 6,629 unique patient prescriptions from 1,632 prescribers and $362.4 million in revenue. In the second quarter of 2026, Attruby's US revenue reached $222.4 million, with growth led by newly treated patients, and management described it as up 211% year on year and the fastest-growing product in the space. BridgeBio is also adding data, such as kidney protection and fewer outpatient heart failure episodes, to widen use.
Q9What should I watch for in the ATTR-CM market?
Three themes: Wainua's July 2026 failure reinforces stabilisers as frontline; FDA scrutiny of promotional claims is intensifying; and real-world data showing 34% lower worsening risk with Attruby is accelerating a market-share shift away from Pfizer.
Three themes stand out. First, the stabiliser-versus-silencer debate. AstraZeneca and Ionis's silencer Wainua missed its primary endpoint in July 2026 and showed no added benefit in patients already on stabilisers, who made up most of the trial. This reinforces stabilizers as frontline therapy, which favours both BridgeBio and Pfizer. Second, scrutiny of promotional claims looks set to increase. The FDA has already challenged Alnylam's survival claims, and Pfizer has continued to be accused of misleading marketing claims. Third, market share. New data, including a recent study showing a 34% lower risk of clinical worsening versus tafamidis, make Attruby the leading stabiliser. With Attruby revenue growing fast and a $4 billion peak-sales model, BridgeBio expects its share to keep rising.