Revenue Guidance Cut Shocks Investors
A New York-based law firm has launched an investigation into Alnylam Pharmaceuticals, Inc. following a dramatic stock price collapse that erased approximately 28% of the company's market value in a single trading session on July 30, 2026.
Kirby McInerney LLP announced it is examining whether Alnylam and its senior management violated federal securities laws after the Cambridge, Massachusetts-based biotechnology company unexpectedly lowered its full-year revenue guidance by roughly $200 million.
The company, founded in 2002 and specializing in RNA interference (RNAi) therapeutics for genetically defined diseases, cited "learnings from the initial phase of our launch in the evolving ATTR-CM market"
when announcing its revised second-quarter 2026 financial results. Alnylam specifically pointed to a "normalization of growth in second line volume after satisfying pent-up demand from patients waiting for a new therapy."
The announcement sent Alnylam shares plummeting $81.14 to close at $205.48, leaving the stock down more than 42% year-to-date in 2026 and trading near its 52-week low.
Context Behind the Decline
The revenue reduction centers on Alnylam's AMVUTTRA (vutrisiran), a treatment for transthyretin amyloid cardiomyopathy (ATTR-CM), a progressive and life-threatening disease caused by misfolded protein deposits in heart muscle. The drug received U.S. FDA approval for ATTR-CM in March 2025 and had initially exceeded expectations, with Alnylam raising its revenue guidance twice during 2025.
Despite crossing $1 billion in quarterly revenue for the first time in the second quarter of 2026, AMVUTTRA's sales of approximately $1.01 billion fell roughly 4% short of analyst expectations, with U.S. sales of $809 million missing consensus estimates by about 2%.
The ATTR-CM patient population in the United States has expanded dramatically from fewer than 5,000 diagnosed cases in 2019 to more than 50,000 in 2025, driven by heightened disease awareness and improved diagnostic techniques. The global ATTR treatment market is projected to reach approximately $16.8 billion by 2030, with major pharmaceutical companies including Pfizer, BridgeBio Pharma, AstraZeneca, and Ionis Pharmaceuticals competing for market share.
Competitive Pressures and Market Dynamics
Alnylam faces competition from both stabilizer therapies such as Pfizer's VYNDAQEL/VYNDAMAX (tafamidis) and BridgeBio's Attruby (acoramidis), as well as other silencer approaches. In early July 2026, AstraZeneca's competing ATTR-CM silencer treatment, Wainua (eplontersen), failed its Phase 3 CARDIO-TTRansform clinical trial, failing to demonstrate statistically significant reductions in cardiovascular death and recurrent cardiovascular events. The trial failure raised broader questions about RNAi silencer therapies in the ATTR-CM market.
Investigation Details
At this stage, no lawsuit has been filed. The law firm's investigation is ongoing to determine whether claims may be brought under federal securities laws. Kirby McInerney LLP, which concentrates in securities, antitrust, whistleblower, and consumer litigation, has recovered billions of dollars on behalf of shareholders in previous securities litigation cases.
Securities class action lawsuits typically require two to four years from initial filing to resolution, progressing through phases including lead plaintiff appointment, motion to dismiss, discovery, class certification, settlement negotiations, and claims distribution.
Investors who purchased Alnylam securities may contact the firm to discuss their rights or interests at no cost. Lauren Molinaro of Kirby McInerney LLP can be reached by email at [email protected].
