Alnylam's Amvuttra Gains Traction in ATTR-CM Market, Challenging Pfizer's Dominance

Alnylam Pharmaceuticals has reported encouraging early signs for its recently approved drug Amvuttra in the treatment of transthyretin amyloid cardiomyopathy (ATTR-CM), signaling a potential shift in the competitive landscape dominated by Pfizer's Vyndaqel franchise.

Amvuttra's Early Market Performance

Amvuttra, which received FDA approval for ATTR-CM on March 20, 2025, has shown promising initial uptake despite limited sales data for the first quarter. Alnylam's Chief Commercial Officer, Tolga Tanguler, highlighted the company's swift progress in securing market access:

"Our first priority out of the gate was the access setup and we're pleased to say it's progressing exactly to plan, enabling the second half growth story that we have portrayed," Tanguler stated during a recent conference call.

The company has achieved formulary placements for Amvuttra at more than half of the 170 health systems responsible for 80% of TTR volume in the U.S. within just four weeks of the label expansion. Tanguler also noted that a "majority" of these systems have already initiated Amvuttra treatment for ATTR-CM patients.

Market Dynamics and Growth Potential

Alnylam CEO Yvonne Greenstreet, M.D., emphasized the significant growth potential in the ATTR-CM market:

"We really are in a category growth story," Greenstreet said. "What we're seeing is continued evidence of a large, growing, and frankly, unsatisfied market and I think we're very excited to be able to participate."

The company estimates that approximately 80% of the addressable patient population remains untreated, suggesting substantial room for expansion. This untapped potential has attracted competition from both Alnylam and BridgeBio, challenging Pfizer's market leadership with its Vyndaqel franchise, which achieved sales of $5.4 billion in 2024.

Financial Performance and Outlook

Alnylam reported combined first-quarter sales of $359 million for its TTR franchise, including Amvuttra and Onpattro, representing a 37% year-over-year increase and a 4% sequential growth. This performance aligns closely with analysts' forecasts of $355 million.

For the full year 2025, Alnylam maintains its guidance for Amvuttra and Onpattro, projecting combined sales between $1.6 billion and $1.725 billion. The company's overall revenue for the first quarter increased by 20% to $594 million, with a full-year guidance of $2.05 billion to $2.25 billion, representing a potential 31% year-over-year increase at the midpoint.

As Alnylam continues to expand its presence in the ATTR-CM market, the pharmaceutical industry watches closely to see how this increased competition will shape patient care and market dynamics in the coming months.