Alnylam Highlights AMVUTTRA Momentum, Resets 2026 TTR Revenue Outlook

Alnylam highlighted continued momentum for its AMVUTTRA treatment in transthyretin-mediated cardiomyopathy, while outlining a pipeline of upcoming clinical catalysts and discussing changes in the market that prompted a revision to its 2026 TTR franchise revenue outlook. Speaking at the Morgan Stanley Global Healthcare Conference, Chief Executive Officer Yvonne Greenstreet said Alnylam’s TTR franchise generated more than $1 billion in revenue during the second quarter. The company received its cardiomyopathy indication for AMVUTTRA in March 2025. Greenstreet attributed the launch performance to data from the HELIOS-B study, access initiatives and physician adoption. She said the study produced results on all-cause mortality across patient subgroups, including patients using stabilizers and those not receiving stabilizers. Alnylam has also continued to generate analyses of cardiac structure and function and extracardiac manifestations, she said. AMVUTTRA’s quarterly subcutaneous dosing also supports adherence, Greenstreet said. She added that most patients can obtain the drug with no out-of-pocket cost, while 90% can access treatment within 10 miles of home. Alnylam has more than 50% market share among physicians who have used AMVUTTRA, according to Greenstreet.

Alnylam revised its 2026 TTR franchise revenue guidance to a range of $4.2 billion to $4.5 billion, representing a $200 million reduction at the midpoint. Greenstreet said the revision reflected a better understanding of how second-line demand has evolved. At the 2025 launch, the company saw pent-up demand from patients who were progressing on existing treatments and awaiting a new option. The company’s business was then approximately balanced between first-line and second-line use. In 2026, that mix has moved toward what Greenstreet described as the broader market’s composition: roughly 80% first-line and 20% second-line. Despite the revised outlook, Greenstreet said market fundamentals remain strong. She cited an estimated 200,000 TTR cardiomyopathy patients in the U.S. and 500,000 globally, with approximately 80% of patients still undiagnosed and untreated. John Kennedy, senior vice president of global commercialization and lead of the TTR franchise, said Alnylam expects modest, gradual net-price reductions over time as volume and experience build. On a proposed change involving the 340B program, Kennedy said the outcome remains uncertain following the comment period, though historically proposed rule changes are generally concluded in November. Kennedy said Alnylam has developed alternate s...