Many investors love the "big mo." That's short for "big momentum." Stocks that are on a roll often keep the good times going.
Three Fool.com contributors think they've found high-flying biotech stocks that could soar even more. Here's why they picked Alnylam Pharmaceuticals (ALNY 0.60%), Axsome Therapeutics (AXSM 0.67%), and Summit Therapeutics (SMMT 0.50%).

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Exciting times for this biotech innovator
Keith Speights (Alnylam Pharmaceuticals): In her comments during Alnylam Pharmaceuticals' first-quarter update, CEO Yvonne Greenstreet said, "2025 is off to a remarkable start." She was exactly right.
Alnylam's share price has jumped close to 23% year to date. The stock has almost doubled over the last 12 months. Alnylam reported 28% year-over-year revenue growth in Q1, driven largely by its U.S. transthyretin amyloidosis franchise.
On March 20, 2025, the U.S. Food and Drug Administration (FDA) approved Alnylam's Amvuttra in treating cardiomyopathy of wild-type or hereditary transthyretin-mediated amyloidosis (ATTR-CM). Only two days earlier, Sanofi won FDA approval of Qfitlia for treating hemophilia. Alnylam licensed the drug to Sanofi and stands to receive tiered royalties of 10% to 15% on all sales.
Amvuttra captured roughly 70% of new patient starts in Q1 despite only receiving a thumbs-up from the FDA late in the quarter. Alnylam expects the drug's U.S. momentum to build in the second half of 2025. It also hopes to win approvals in Japan in Q2 and in the European Union in Q3. Analysts think Amvuttra will become a huge blockbuster drug for Alnylam, with peak annual sales in the ballpark of $7.9 billion by 2035.
More good news could be on the way. Alnylam plans to announce results from a phase 2 study evaluating zilebesiran in treating hypertension later this year. The company hopes to advance the drug to phase 3 testing in the second half of 2025. It also intends to move nucresiran into late-stage testing as a treatment for ATTR-CM within the next month or so.
Wall Street is largely bullish about this stock, with 24 of the 33 analysts surveyed by LSEG rating it as a "buy" or a "strong buy." I agree with this optimism. Alnylam should have plenty of room to run.
There is plenty of upside left for this stock
Prosper Junior Bakiny (Axsome Therapeutics): Share prices of Axsome Therapeutics, a mid-cap biotech, are up by 234% in the past three years thanks to solid clinical and regulatory progress. Notably, the company earned FDA approval for Auvelity, a therapy for major depressive disorder, in 2022. Then there is Symbravo, a migraine treatment, that earned the nod in January.
Axsome Therapeutics' top line is growing rapidly, with Auvelity leading the charge. In the first quarter, the company's revenue came in at $121.5 million, up 62% year over year.
The good news is that there are more catalysts ahead that could jolt the stock price. Axsome Therapeutics has a large late-stage pipeline that should lead to more approvals and label expansions. For example, AXS-05, the generic name for Auvelity, aced late-stage clinical trials in treating Alzheimer's disease agitation. The company will soon seek approval for the medicine in this indication.
The company is also inching closer to a regulatory submission for AXS-12, an investigational medicine for cataplexy in narcolepsy patients. That only scratches the surface of Axsome Therapeutics' pipeline. The drugmaker should see over half a dozen late-stage clinical trial readouts, regulatory submissions, or approvals in the next two years.
And as the company makes progress, its financial results will improve. Axsome Therapeutics is slowly establishing itself as a notable player in the biotech industry. So, despite its shares crushing the market over the past three years, it's not too late to buy the stock.
This stock may not have reached its peak just yet
David Jagielski (Summit Therapeutics): After soaring a staggering 440% in the past 12 months, you might think that Summit Therapeutics stock might be running out of steam. But while its near-$18 billion valuation is high, especially for a company which doesn't even have an approved product yet, it's possible that it could still go higher.
Everything hinges on whether its cancer treatment, ivonescimab, is in fact the real deal or not. In a recent clinical trial, ivonescimab showed that it was able to reduce the risk of death or disease progression in patients with metastatic or locally advanced non-small cell lung cancer by 49%, when compared to Merck's top-selling cancer drug, Keytruda.
The problem, and what may be limiting the healthcare stock from even more gains right now, is that the study was based in China. For regulators in the U.S. to approve the drug, they'll likely want to see a more diverse study, which can confirm its effectiveness.
Summit is working on global trials involving ivonescimab, and if the data proves to be encouraging, then it might not be a surprise to see the stock surge even higher in value. Keytruda has generated tens of billions of dollars for Merck over the years, and if Summit is sitting on a potentially better drug than that, it's easy to see why investors may still have a lot of reasons to remain bullish.
Investors, however, should tread carefully because there is considerable risk with the stock, as the business isn't generating revenue and there's not much else to fall back on right now besides ivonescimab; if clinical trial results prove to be underwhelming from a wider and more diverse group of participants, then a significant sell-off could ensue.