Transthyretin amyloid cardiomyopathy (ATTR-CM) is a progressive heart disease that was once considered rare and untreatable and is now one of the fastest-growing cardiovascular drug markets. Pfizer's Vyndamax was the first treatment in the market and now faces scrutiny over its price, its net-versus-list economics and its disease-awareness marketing. Vyndamax is now being challenged by BridgeBio’s Attruby and Alnylam’s Amvuttra.
Core Patient Questions
What is ATTR-CM?
Transthyretin amyloid cardiomyopathy (ATTR-CM) is a disease in which a liver-made protein called transthyretin misfolds and deposits as amyloid fibrils in the heart muscle. The walls of the heart stiffen and thicken, which limits filling and leads to heart failure and rhythm problems. It typically presents in older adults, is more common in men and Black individuals, and is frequently mistaken for ordinary heart failure with preserved ejection fraction. About 100,000 people in the U.S. and 500,000 worldwide may have the condition, although only a fraction are diagnosed. Untreated, median survival is between two and four years after diagnosis. Until 2019 there were no disease-specific drugs; care consisted of heart failure medicines and, rarely, heart or combined heart-liver transplantation. Today three drug classes are approved, which has turned ATTR-CM into a multibillion-dollar market.
What are the early warning signs of ATTR-CM?
Early symptoms are easy to dismiss: shortness of breath on exertion, fatigue, ankle swelling, dizziness and palpitations from atrial fibrillation. Some of the most useful clues appear outside the heart and years before heart failure. Clinicians have noted that low voltage on an electrocardiogram appears in fewer than half of cases, so a normal tracing does not rule the disease out. Anyone with several of these features, especially an older man with heart failure and carpal tunnel history, should ask a cardiologist about amyloid testing.
What causes transthyretin amyloid cardiomyopathy?
The cause is misfolding of transthyretin (TTR), a transport protein made mainly in the liver. Normally TTR circulates as a stable four-part complex. When the complex falls apart, the pieces misfold, clump into amyloid fibrils and settle in the heart. Two mechanisms explain why this happens. In wild-type disease, the normal TTR gene is unchanged and misfolding is linked to aging, which is why most patients are over 65. In hereditary disease, a variant in the TTR gene makes the protein less stable. The most common variant in the United States is V122I, now also named V142I, carried by roughly 4% of Black Americans. Drugs work at two points: stabilizers such as tafamidis keep the four-part complex together, while silencers such as vutrisiran reduce how much TTR the liver produces.
How is ATTR-CM diagnosed?
Diagnosis usually starts with suspicion from an echocardiogram or cardiac MRI that shows thick heart walls. The next step is excluding AL amyloidosis with blood and urine tests for monoclonal proteins. If those tests are negative, a bone scintigraphy scan can confirm ATTR-CM without a heart biopsy: any uptake of tracer was more than 99% sensitive but only 86% specific, which is why the lab tests matter. A large UK study found that scintigraphy alone cannot be used in isolation to diagnose ATTR-CM, but combined with biochemical tests it reliably establishes the diagnosis. Genetic testing of the TTR gene then separates hereditary from wild-type disease. Biopsy is still needed when the picture is unclear. The noninvasive route has shortened what was once a long, invasive workup, though many patients are still diagnosed late or missed.
Is ATTR-CM hereditary?
Sometimes. The hereditary form (ATTRv-CM) is caused by a variant in the TTR gene and is passed in an autosomal dominant pattern, meaning a child of an affected parent has a 50% chance of inheriting the variant. Not everyone who inherits a variant develops disease, and onset age varies. In the U.S. the common V122I variant is carried by about 4% of Black Americans, who may be underdiagnosed and have limited access to treatment, according to a review of racial and ethnic disparities in diagnosis and management. Wild-type ATTR-CM, by contrast, is not inherited and arises with age. Because a hereditary result has implications for relatives, genetic testing and counseling are recommended after diagnosis. A positive test in a family member does not by itself mean the heart disease has started; cardiologists typically recommend periodic surveillance for carriers, and treatment decisions depend on whether cardiac amyloid is present.
What is the difference between hereditary and wild-type ATTR-CM?
Wild-type ATTR-CM arises when the normal TTR protein misfolds with age. It mostly affects men in their seventies and is usually confined to the heart, although carpal tunnel syndrome and spinal stenosis may precede it. Hereditary ATTR-CM results from a TTR variant, can start earlier and may also involve nerves, causing neuropathy. The V122I variant behaves like wild-type disease in many ways, but patients with V122I had worse quality of life at diagnosis and poorer survival than wild-type patients in a UK cohort. Importantly for treatment, current drugs are approved for ATTR-CM regardless of whether it is hereditary or wild-type. Stabilizers and the silencer vutrisiran were studied in mixed populations that included both forms. The main practical difference is therefore family implications and the need to watch for neurologic involvement in hereditary cases.
What is the difference between ATTR and AL amyloidosis?
Both conditions deposit amyloid in the heart, but they have different causes and urgency. AL amyloidosis arises when abnormal plasma cells in the bone marrow make light chains that misfold, whereas ATTR arises from liver-derived transthyretin. AL is a hematologic emergency treated with plasma-cell-directed chemotherapy and can progress in weeks to months. ATTR progresses more slowly and is treated with TTR-directed drugs. The distinction matters because scintigraphy can mislead: in the large UK series, of 122 patients with grade 1 scans and a monoclonal protein, 106 (87%) had AL. Cardiologists therefore require blood and urine tests for monoclonal proteins before accepting a noninvasive ATTR diagnosis, and biopsy if they are positive. Treating AL as ATTR, or the reverse, can be harmful, so the workup should always exclude light-chain disease first, ideally with a hematologist involved if any monoclonal protein appears.
What is the life expectancy for someone with ATTR-CM?
Without treatment, median survival is about two to four years from diagnosis, and it is shorter for patients with advanced heart failure symptoms. Treatment extends survival, particularly when started early. In BridgeBio's phase 3 ATTRibute-CM trial, 632 patients received either acoramidis 800 mg twice daily or a placebo for 30 months. The main analysis combined and ranked deaths from any cause, hospital stays for heart problems, a heart-stress blood marker called NT-proBNP, and walking ability. Acoramidis performed better overall, with a win ratio of 1.8. Among patients who remained on treatment, 81% were alive at 30 months, compared with 74% of those receiving placebo, and hospital stays for heart problems were about 50% less frequent.
What treatments are available for ATTR-CM?
Three disease-specific drugs are available in the U.S. Pfizer's tafamidis stabilizes the TTR complex. BridgeBio's acoramidis (Attruby), another stabilizer, was launched in late 2024. It is an oral medicine taken twice daily. Alnylam's Amvuttra (vutrisiran), an RNA interference drug given by injection, gained its ATTR-CM approval in March 2025. All are paired with standard heart failure care, including diuretics, and clinicians monitor for arrhythmias. Transplant is reserved for select younger patients. BridgeBio presented a matching-adjusted indirect comparison at ESC's 2026 Heart Failure congress suggesting Attruby cut cardiovascular hospitalizations 34% relative to Vyndamax with a comparable safety profile.
Market and Controversy Information
Why is Pfizer's Vyndamax so expensive?
Pfizer launched tafamidis in 2019 at a list price of $225,000 per year, which TCTMD reported made it the most expensive cardiovascular drug on the market, and heart failure physicians called the price outrageous. The list price has since risen to roughly $268,000 per year. Critics argue the price far exceeds value: a public comment filed with the FDA, citing a 2023 analysis, compared the U.S. price with $93,600 in Japan and $160,000 in the United Kingdom.
Is Vyndamax cost-effective compared with other ATTR-CM treatments?
Analysts say not at its list price. The Institute for Clinical and Economic Review (ICER) concluded in October 2024 that tafamidis would meet common cost-effectiveness thresholds at $13,600 to $39,000 per year, against a list price near $268,000. Its draft report had said tafamidis needed at least a 96% discount; the final range was higher. A 2025 analysis in the Journal of Managed Care & Specialty Pharmacy used a net price of $194,291 per year as a placeholder and found cost-effectiveness ratios far above accepted thresholds.
Has Pfizer's marketing and promotion of Vyndamax influenced ATTR-CM diagnosis and prescribing?
Pfizer’s marketing helped establish Vyndamax as an ATTR-CM treatment when it faced no direct competition. However, its promotional claims have also drawn scrutiny. In 2025, a German court ordered Pfizer to stop describing Vyndamax as delivering “near-complete stabilization” of transthyretin, finding that the claim was not supported by the available evidence or the product label. Pfizer has also been criticized for claiming that Vyndamax is the “one standard of care” and “the only” once-daily capsule, arguing that such messaging risks obscuring the arrival of competitor treatments such as BridgeBio’s Attruby. Serious concerns have therefore been raised over Pfizer’s use of misleading marketing claims to protect Vyndamax’s market share at the expense of newer alternatives.
Will competition from Attruby and Amvuttra reduce the price of ATTR-CM treatment?
Not yet, at least on list price. BridgeBio priced Attruby at $18,759 per 28 days, about $244,000 a year, making it by far the cheapest drug to treat ATTR-CM. That is a major discount to Vyndamax at roughly $268,000 and Amvuttra at about $450,000 a year before discounts, according to Citi analysts. Another barrier to cheaper ATTR-CM treatments is Pfizer’s efforts to protect drug exclusivity: Pfizer settled with generic makers so that generic Vyndamax cannot launch before June 1, 2031, subject to other litigation. However, other analysts are more bullish, arguing that Attruby’s strong results and cheaper cost make BridgeBio a strong candidate to gain further market share and drive the cost of ATTR-CM treatment down.
How big is the ATTR-CM market, who are the key players and what is the outlook?
Independent analysts expect continued growth. Jefferies has said the market is on a trajectory to more than $20 billion in annual U.S. sales, while Leerink projected total ATTR drug sales of $16.7 billion in 2028 and $17.1 billion in 2035 against Wall Street consensus of $15.3 billion and $25.5 billion. Pfizer's tafamidis franchise generated $6.3 billion in worldwide sales in 2025. BridgeBio's Attruby, launched late 2024, earned $362 million in 2025, with 7,804 prescriptions written by February 20, 2026. Jefferies analysts expect Attruby to surpass $1 billion in annual global sales in 2026. Alnylam's Amvuttra reported ATTR-CM sales of only circa $150 million in the second quarter of 2025.
What did AstraZeneca's CARDIO-TTRansform failure mean for the ATTR-CM market?
On July 9, 2026, AstraZeneca and Ionis announced that their phase 3 CARDIO-TTRansform trial of eplontersen (Wainua) had missed its primary endpoint, a composite of cardiovascular mortality and recurrent cardiovascular events through week 140. The trial enrolled 1,432 patients at 130 sites in 20 countries, making it the largest ATTR-CM study to date.
The Wainua trial failure showed that among patients already on a stabilizer, no incremental effect was observed through the addition of a silencer treatment, making stabilizers the primary treatment for ATTR-CM. Alnylam, which manufactures the silencer Amvuttra, has suffered from the announcement, with analysts from Jefferies noting that the value proposition of silencers has been “diminished”. BridgeBio's chief executive described a "stabilizer-first" market, a company view that Jefferies analysts echoed in saying combining a silencer with a stabilizer offers no meaningful additive benefit. Trade press reported that BridgeBio shares rose after the announcement. Stabilizers now look to be the way forward in ATTR-CM. This is great news for BridgeBio, whose Attruby treatment is the leading stabilizer in the market.
Why has the FDA criticized Alnylam's Amvuttra marketing, and why did its stock fall?
In 2026 the FDA sent Alnylam an untitled letter over the Amvuttra consumer website, saying that survival claims drawn from the open-label extension of HELIOS-B created a misleading impression because that portion of the study could not support the conclusions. Fierce Pharma reported the website claimed the risk of death was 36% lower over 3.5 years, and that it was Alnylam's second untitled letter since September 2025; the first, about a TV ad, was closed in November.
On July 30, 2026, Alnylam lowered its 2026 TTR product sales guidance by about $200 million, citing normalization of second-line volume after pent-up demand, and shares fell as much as 28%. Several law firms have announced investigations of possible securities-law violations. These are solicitations to investors, not findings, and no lawsuit outcome has been reported.