Key Takeaways:
Alnylam Pharmaceuticals shares plunged 28% after the company cut its 2026 TTR product sales guidance by about $200 million.
"Alnylam lowered its total projected TTR net product revenues for full-year 2026 to reflect learnings from the initial phase of our launch in the evolving ATTR-CM market," the company said in its second-quarter earnings release on July 30.
The stock fell as much as $81.25, or 28.35%, in intraday trading on July 30, erasing billions in market value. At least three law firms — Glancy Prongay Wolke & Rotter, Law Offices of Howard G. Smith, and Law Offices of Frank R. Cruz — have announced investigations into whether Alnylam violated federal securities laws.
The investigations center on whether the company misled investors about the durability of demand for its TTR therapies in the ATTR cardiomyopathy market. Alnylam attributed the shortfall to "normalization of growth in second line volume after satisfying pent-up demand from patients waiting for a new therapy," suggesting the initial launch surge was not sustainable.
Alnylam's TTR franchise includes Onpattro (patisiran) and Amvuttra (vutrisiran), both approved for transthyretin-mediated amyloidosis. The company had been counting on expansion into the larger ATTR-CM patient population to drive growth. The $200 million guidance reduction represents roughly 15% to 20% of prior full-year TTR revenue expectations, based on analyst estimates.
The investigations will examine whether company executives made materially false or misleading statements about the launch trajectory and market demand. Shareholders who purchased Alnylam securities may be eligible to participate in class-action claims.
The guidance cut and subsequent investigation raise questions about Alnylam's ability to sustain growth in the ATTR-CM market beyond the initial pent-up demand phase. Investors will watch for any additional disclosures in the company's upcoming SEC filings and for potential class-action certification hearings in the months ahead.
This article is for informational purposes only and does not constitute investment advice.
