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.