Alnylam Pharmaceuticals lost nearly a third of its market value Wednesday after the RNAi drugmaker’s second-quarter numbers came in behind Wall Street’s estimates and management trimmed its full-year sales outlook for its flagship TTR franchise.
The company reported second-quarter revenue of $1.29 billion, up 67% from a year earlier but short of the $1.31 billion analysts had penciled in. Adjusted earnings of $1.84 a share missed the $2.13 consensus estimate by nearly 14%. On a GAAP basis, the gap was wider still: EPS of $1.21 against a $1.49 estimate.
None of that alone explains a decline this steep. The number that moved the stock was the guidance cut.
Why the TTR guidance cut matters more than the earnings miss
Alnylam lowered its full-year 2026 revenue guidance for its TTR product line — the AMVUTTRA and Onpattro franchise that treats transthyretin-mediated amyloidosis — to a range of $4.2 billion to $4.5 billion, down from its prior forecast. According to StockTitan’s reporting on the earnings release, CEO Yvonne Greenstreet attributed the revision to early-launch dynamics in the ATTR-CM market, specifically a normalization of second-line patient volume after the initial wave of pent-up demand was satisfied.
That’s the mechanism worth sitting with. AMVUTTRA’s launch curve front-loaded a backlog of patients who’d been waiting for a therapy option. Once that backlog clears, growth reverts to a slower, steadier new-patient rate. Guidance built on the front-loaded pace was always going to need a reset — the question the market answered Wednesday was how investors would price that reset once it became official rather than speculative.
AMVUTTRA itself still grew. Net product revenue for the drug hit $1.01 billion in the quarter, more than double the $492 million booked a year earlier — but that figure missed the $1.05 billion the Street wanted. Growth was real. It just wasn’t enough.
Where the rest of the portfolio landed
| Product | Q2 2026 Net Revenue | YoY Change | Vs. Estimate |
|---|---|---|---|
| AMVUTTRA | $1.01B | +105% | Missed ($1.05B est.) |
| Givlaari | $89.8M | +11% | Beat ($83.8M est.) |
| Oxlumo | $52.1M | +11% | Missed ($54.3M est.) |
| Onpattro | $18.5M | -65% | Missed ($23.5M est.) |
Onpattro’s decline is not new information — the drug has been ceding share to AMVUTTRA within Alnylam’s own portfolio for several quarters, part of a deliberate transition rather than a competitive loss. Collaboration revenue, a smaller line item, fell 23% to $47.2 million.
What the screenshot showed
A real-time quote captured during Wednesday’s regular session — 1:06 p.m. EDT, market open — showed shares trading at $200.65, down $85.97, or 29.99%, from the prior close of $286.62. The stock had opened the session at $225.03 and traded as low as $200.31 intraday, a level essentially matching where it sat at the time the quote was pulled. Volume at that point in the session, 5.3 million shares, already ran more than four times the stock’s 30-day average of roughly 1.28 million — a sign the move was driven by broad institutional repositioning rather than thin, choppy trading.
That reading has not been independently re-verified against a live quote as of this writing, since the market is closed at the time this piece was filed. It is presented here as the trading-session snapshot the user captured, not as a confirmed current price.
The pipeline the selloff overshadowed
Buried under the guidance news, Alnylam also disclosed two new Phase 2 study initiations during the quarter — ALN-6400 in von Willebrand disease and mivelsiran in Down syndrome-associated Alzheimer’s disease — alongside new HELIOS-B data presented at the Heart Failure 2026 conference supporting vutrisiran’s durability across patient subgroups. None of it moved the stock Wednesday. Pipeline data rarely offsets a guidance cut in the same session — the market tends to price the near-term revenue signal first and revisit platform value later, if the thesis holds.
The next scheduled catalyst is Alnylam’s third-quarter report, expected around Oct. 29, 2026. That release will show whether the AMVUTTRA growth deceleration Alnylam flagged this week was a one-quarter reset or the start of a longer trend — the distinction that will determine whether Wednesday’s move was an overreaction or a correct repricing.
This article is for informational purposes only and does not constitute financial advice.
