BioMarin Pharmaceutical Inc. (BMRN) is writing a big check to expand its rare disease franchise. The company announced Friday it's acquiring Amicus Therapeutics, Inc. (FOLD) for roughly $4.8 billion in cash, and investors in both companies seem pretty happy about it.
The deal values Amicus at $14.50 per share, which works out to a 33% premium over where the stock closed Thursday. Look back a bit further and the premium gets even juicier: 46% above the 30-day average price and 58% above the 60-day average. Both boards have signed off unanimously, and Amicus's board is actively encouraging shareholders to vote yes.
What BioMarin Is Actually Buying
This isn't just about boosting revenue numbers. BioMarin is getting its hands on two commercially proven treatments for lysosomal storage disorders, a category of rare genetic diseases that fits perfectly with its existing business.
First up is Galafold (migalastat), the first oral therapy for Fabry disease. Then there's the Pombiliti (cipaglucosidase alfa-atga) and Opfolda (miglustat) combination, a two-part treatment regimen for Pompe disease. Together, these therapies pulled in $599 million in net revenues over the past four quarters, which is real money.
The Galafold story gets particularly interesting when you consider the patent timeline. Thanks to recent litigation settlements, U.S. exclusivity now extends through January 2037. That's over a decade of protected market position, which makes the economics here look considerably more attractive.
There's also a potential wildcard in the deal: DMX-200, a small molecule in Phase 3 development for focal segmental glomerulosclerosis (FSGS), a rare and deadly kidney disease. Amicus holds the U.S. rights, and if it pans out, it could be a first-in-class treatment.
The Strategic Logic
Alexander Hardy, BioMarin's president and CEO, positioned this as a natural combination of like-minded companies. "Amicus, like BioMarin, is a company that has been profoundly dedicated to transforming care for patients with rare diseases since its founding, developing and bringing to market important therapies for individuals living with Fabry disease and Pompe disease."
He added that "BioMarin's scale of operations, including our global commercial footprint and industry-leading, in-house manufacturing capabilities, make the combination of these companies an exceptional strategic fit."
Translation: BioMarin thinks it can sell these drugs better and make them more efficiently than Amicus can on its own.
The Financial Math
BioMarin expects the deal to accelerate its long-term growth rate through 2030 and beyond. More immediately, the acquisition should start contributing revenue the moment it closes, expected in the second quarter of 2026 pending shareholder approval and antitrust clearances.
The company is projecting the deal will be accretive to non-GAAP diluted earnings per share within 12 months of closing, and substantially accretive starting in 2027. BioMarin also says it plans to reduce gross leverage to below 2.5 times within two years after the deal wraps up. As of September 30, 2025, the company had $1.25 billion in cash and equivalents on hand.
The market's verdict came swiftly: BMRN shares jumped 19.89% to $62.29, while FOLD shares surged 30.95% to $14.27 at publication on Friday.
