NEW YORK, July 30, 2026, 13:02 EDT – Shares of Alnylam Pharmaceuticals NASDAQ:ALNY fell 28% after the firm revised its Amvuttra sales guidance downward.
- Shares were last at $205.25, a drop of 28.4%, after reaching a low of $200.44.
- Transthyretin product revenue outlook was reduced to a range of $4.2 billion to $4.5 billion.
- The updated midpoint calls for average TTR sales of $1.205 billion per quarter in the second half.
Alnylam stock dropped 28.4% to $205.25 during active trading on the Nasdaq on Thursday. The company revised its 2026 transthyretin (TTR) product revenue forecast lower by $200 million at the midpoint.
Based on the SEC’s share count from July 24, an estimated $10.9 billion in equity value was wiped out. This initial calculation represented approximately 54 times the lowered TTR guidance. Shares continued to trade.
The overall shift in revenue was less pronounced. Collaboration and royalty guidance increased by $150 million at the midpoint, resulting in the total-revenue midpoint falling by roughly $50 million.
This is the indication for investors. The response indicates that shareholders reassessed the sustainability of Amvuttra sales, rather than simply factoring in a single year’s reported revenue.
The decline was limited to the company. At around 12:47 p.m. EDT, other ATTR-related shares and the biotech index saw much smaller movements.
| Security | Price | Session move |
|---|---|---|
| Alnylam Pharmaceuticals NASDAQ:ALNY | $205.25 | -28.4% |
| BridgeBio Pharma NASDAQ:BBIO | $81.86 | -2.0% |
| Pfizer NYSE:PFE | $24.77 | -1.5% |
| Ionis Pharmaceuticals NASDAQ:IONS | $53.07 | -1.8% |
| SPDR S&P Biotech ETF (NYSEARCA:XBI) | $149.24 | +0.9% |
The quarter continued to perform well overall. Total revenue increased by 67% to $1.291 billion. Product sales jumped 74% to $1.172 billion. Amvuttra marked a milestone as Alnylam’s first product to generate more than $1 billion in revenue for a single quarter.
Adjusted earnings reached $1.84 per share, topping analyst estimates. However, revenue fell short of expectations, missing the approximately $1.32 billion forecast by nearly $31 million. Amvuttra is a gene-silencing treatment administered every three months for both cardiac and nerve types of transthyretin amyloidosis.
Company filings reveal a quarter-on-quarter mix that appears less favourable.
| Metric | Q1 2026 | Q2 2026 | Sequential change |
|---|---|---|---|
| Amvuttra product revenue | $889.9 million | $1,011.8 million | up 13.7% |
| Total TTR product revenue | $910.4 million | $1,030.2 million | up 13.2% |
| Total product revenue | $1,036.1 million | $1,172.1 million | up 13.1% |
| Non-GAAP operating income | $338.8 million | $318.1 million | down 6.1% |
| Cost of goods/product revenue | 20.0% | 25.4% | rise of 5.4 points |
Product sales increased by 13.1%, though adjusted operating income declined 6.1%. Product costs accounted for 25.4% of sales, rising from 20.0%. Alnylam attributed the higher costs largely to increased royalty rates for Amvuttra.
Chief Financial Officer Jeff Poulton was direct. “We didn’t get it right with our original guidance. We own that.” He explained that early second-line demand was boosted by patients who had been waiting to switch therapies. MarketBeat
The updated ranges decrease product expectations but do not cut back on intended research or commercial expenditures.
| 2026 measure | Previous guidance | Updated guidance | Midpoint change |
|---|---|---|---|
| TTR product revenue | $4.4B-$4.7B | $4.2B-$4.5B | -$200M |
| Rare-disease product revenue | $0.5B-$0.6B | Unchanged | — |
| Total product revenue | $4.9B-$5.3B | $4.7B-$5.1B | -$200M |
| Collaboration and royalty revenue | $0.4B-$0.5B | $0.575B-$0.625B | +$150M |
| Non-GAAP R&D and SG&A | $2.7B-$2.8B | Unchanged | — |
| Derived total-revenue midpoint | $5.55B | $5.50B | -$50M |
Initial estimate based on the midpoint of each range provided by the companies.
Alnylam reported $1.941 billion in TTR sales for the first half. With the midpoint now updated, $2.409 billion in TTR revenue is required for the second half. To achieve this, average sales per quarter would need to hit $1.205 billion, which is 16.9% higher than the second quarter.
Even at the lower threshold, a greater run rate is necessary. Company results analysis indicates this hurdle must be met.
| Updated TTR goal | Annual guidance | Revenue required H2 | Average per H2 quarter | Change from Q2 |
|---|---|---|---|---|
| Lower bound | $4.20B | $2.259B | $1.130B | +9.7% |
| Median | $4.35B | $2.409B | $1.205B | +16.9% |
| Upper bound | $4.50B | $2.559B | $1.280B | +24.2% |
Chief Executive Yvonne Greenstreet said that first-line starts currently account for “about 80% of category growth.” The commercial focus is evident. Demand from newly diagnosed patients is expected to offset declining switch demand. MarketBeat
Management believes that approximately 80% of patients with ATTR cardiomyopathy do not receive treatment. Alnylam is increasing diagnosis initiatives and extending its outreach to prescribers. These numbers reflect company projections rather than outside evaluations.
Risks: Even with sales at the lower end of the guidance for the second half, the figure is still 9.7% higher than Q2. However, increased royalty payments are squeezing product margins. Additional risks include a slower adoption rate for first-line use, changes to reimbursement, or negative developments in clinical trials, any of which could prompt a further adjustment.
The next assessment concerns third-quarter TTR revenue. If the result falls short of about $1.13 billion, additional efforts will be needed in the fourth quarter.
