Alnylam stock tumbled Friday — while BridgeBio stock popped — after Alnylam Pharmaceuticals' rival to a Pfizer heart disease drug fell short in a lengthy study.
Numerous companies are working to treat ATTR amyloidosis with cardiomyopathy. In this disease, abnormal protein builds up on the heart, causing damage. Pfizer sells an approved treatment called Vyndaqel, while Alnylam is testing a drug called vutrisiran. BridgeBio Pharma's acoramidis could gain approval as early as November. AstraZeneca and Ionis Pharmaceuticals are also teamed up on another treatment for the disease.
In Alnylam's study, patients received vutrisiran for up to 42 months. After 30 months, patients had a 31% reduction in the risk of death, a company spokesperson told Investor's Business Daily. Earlier, however, the presentation included an error that suggested the reduction was less than 14%, according to analysts' reports.
But investors were looking for a 32% risk reduction after 30 months, William Blair analyst Myles Minter said in a report. Vutrisiran didn't meet that bar. Through 42 months, patients had a 36% lower risk of death.
"Objectively, this data appears to be short of the aforementioned investor bar and hence the premarket trading weakness," he said.
Alnylam stock plunged 8.5% to 262.69. Alnylam shares rank fourth on the IBD 50 list of elite growth stocks. BridgeBio stock jumped 13.1% to 27.85. Pfizer stock rose a fraction to 29.03. Ionis stock sank 1.1% to 47.16, while AstraZeneca shares rose 0.4% to 87.62.
Alnylam shares have run up 50% this year and have a nearly perfect IBD Digital Relative Strength Rating of 98. This means Alnylam stock ranks in the leading 2% of all stocks when it comes to 12-month performance. The Composite Rating, a measure of fundamental and technical strength, is a strong 96 out of a total 99.
Alnylam Stock: Taking On Pfizer, BridgeBio
The cardiomyopathy space is heating up. Pfizer's Vyndaqel, the only approved drug, notched $3.32 billion in sales last year. This year, analysts surveyed by FactSet expect the drug to generate $4.84 billion in sales.
Vutrisiran uses a different mechanism to tackle cardiomyopathy. It silences the gene responsible for making the abnormal protein. Vyndaqel and acoramidis are both stabilizers. They prevent the abnormal protein from spreading and stabilize it. AstraZeneca and Ionis' drug targets antisense, the non-coding DNA strand of a gene, to prevent the protein from ever being created.
Mizuho Securities analyst Salim Syed says there is "nothing suggestive that vutrisiran is better vs. acoramidis," in Alnylam's study.
Alnylam tested vutrisiran in patients receiving background treatment for cardiomyopathy, including Pfizer's Vyndaqel. Across all patients, vutrisiran reduced the risk of death or cardiovascular events by 28% after 36 months. In patients who received vutrisiran alone, that was a 33% reduction. BridgeBio, on the other hand, recorded a 42% relative risk reduction after 30 months.
Further, patients who received vutrisiran underperformed acoramidis recipients in the six-minute walk test and a questionnaire of symptoms. The former examines how far patients can walk for six minutes and is a considered a key measure of disease severity.
Syed has an outperform rating on BridgeBio stock.
BridgeBio Estimates Could Rise
Leerink Partners analyst Mani Foroohar says it's a "tough sell" to suggest Alnylam could gain Food and Drug Administration approval for vutrisiran as a first treatment for ATTR cardiomyopathy.
"While management suggested vutrisiran may benefit patients early in disease by preserving functional capacity and quality of life, consensus projections for vutrisiran likely need to come down significantly, while BBIO acoramidis will see some upward pressure on analyst projections," he said in a report to clients.
FactSet-polled analysts currently project $8.7 million from acoramidis this year, growing to $110.3 million next year. For vutrisiran, they estimate $67 million in 2025 sales and $265 million in 2026. Goldman Sachs analyst Salveen Richter sees a peak of $5.3 billion in 2035 sales for vutrisiran.
"Overall, we see the totality of data as positive and supportive of a strong revenue trajectory, particularly in the context of the about 10% penetrated market and physician enthusiasm for the distinct mechanism/profile," she said in a client note.
Mixed Views On Alnylam's Chances
Leerink's Foroohar has a market perform rating on Alnylam stock. He says it's not surprising to see Alnylam shares down with BridgeBio stock up on the news. William Blair's Minter, on the other hand, remains upbeat on Alnylam shares. He rates the stock an outperform.
"We still think vutrisiran is an effective therapy that will be competitive in the growing (ATTR cardiomyopathy) market and we would be buyers on Alnylam weakness today," he said.
Follow Allison Gatlin on X, the platform formerly known as Twitter, at @IBD_AGatlin.
