Key Highlights

  • Shares are trading 19.01% lower at $188.23 on Thursday, October 29, 2026, from a prior close of $232.40.
  • Total revenues grew 17% to $1.458 billion, and net product revenues grew 52% to $1.292 billion.
  • Amvuttra sales climbed 65% to $1.130 billion, while Onpattro dropped 50% to $19.6 million.
  • Net income of $2.167 billion included a tax benefit of roughly $1.9 billion from releasing valuation allowances.
  • Cash, equivalents and marketable securities totaled about $3.6 billion at September 30.

Alnylam Stock Decline: What Explains a 19% Fall After a Revenue Beat?

Alnylam Pharmaceuticals (NASDAQ:ALNY) shares are trading 19.01% lower at $188.23 on Thursday, October 29, 2026, compared with a prior close of $232.40. The stock reached a fresh 52-week low of $179.87 during the session.

Third-quarter results arrived the same day, and the release gives no explanation for the drop. Total revenues of $1.458 billion compared with $1.249 billion a year earlier and topped a market estimate of about $1.43 billion. A research firm also lowered its rating and set a $225 price target that day.

Alnylam develops RNA interference medicines for rare and common diseases, with marketed products for transthyretin amyloidosis, acute hepatic porphyria and primary hyperoxaluria.

Alnylam Amvuttra Sales: How Quickly Is the Transthyretin Business Expanding?

Amvuttra net product revenue increased 65% to $1,130.4 million from $685.3 million. Onpattro declined 50% to $19.6 million, bringing total transthyretin revenue to $1,150.0 million, a 59% gain. Amvuttra was about $1.01 billion in the second quarter, which implies sequential growth near 12% (calculated).

Rare disease revenue grew 12% to $142.0 million. Total net product revenues came to $1,291.9 million, up 52%.

Collaboration revenue dropped 80% to $71.5 million because the year-earlier quarter included a $300.0 million Roche milestone connected to the first patient dosed in a zilebesiran Phase 3 trial. Royalty revenue more than doubled to $94.7 million.

Alnylam Earnings Quality: How Much of the $2.17 Billion Profit Came From a Tax Benefit?

GAAP net income was $2,167.3 million, or $15.72 per diluted share, compared with $292.7 million and $2.14 a year earlier. Non-GAAP diluted EPS was $16.26. An income tax benefit of $1,871.5 million from releasing valuation allowances on deferred tax assets drove the result, with pre-tax income at $295.8 million.

GAAP operating income slid 6% to $345.8 million. Cost of goods sold rose to 28.0% of net product revenues from 23.2%, R&D rose 14% to $408.5 million and SG&A rose 6% to $342.0 million.

At the current price and 133.8 million basic weighted shares, market capitalization is near $25.2 billion (calculated). Cash and securities were about $3.6 billion, up from $2.9 billion at year-end.

Alnylam Outlook and Pipeline: What Was Held and What Expanded?

The company reiterated guidance: transthyretin net product revenues of $4.2 billion to $4.5 billion, rare disease revenues of $500 million to $600 million, total net product revenues of $4.7 billion to $5.1 billion, and collaboration and royalty revenues of $575 million to $625 million. The transthyretin range was lowered by $200 million on July 30, when shares fell sharply.

The TRITON-CM nucresiran trial target rose to about 2,250 patients from 1,750, with launch still expected by 2030. Brezosiran, partnered with Regeneron (NASDAQ:REGN), produced a mean 60% to 64% decline in a Huntington's disease marker in the top dose group, and a pivotal study is planned for 2027.

What to Watch Next: HELIOS-B Extension Results and the Cemdisiran Decision

Two-year HELIOS-B open-label extension data are scheduled for the American Heart Association meeting from November 6 to 9, followed by an indirect comparison of vutrisiran and acoramidis from November 15 to 18. A regulatory decision on partnered cemdisiran is targeted for November 2026.