BioMarin drug acquired in buyout misses goal in rare disease study

An article from BioMarin drug acquired in buyout misses goal in rare disease study Tested in a condition known as ENPP1 deficiency, the treatment failed a trial goal that’s important to regulators, spurring doubts about its approval prospects. Published May 19, 2026 Delilah Alvarado Reporter Share Copy link Email LinkedIn X/Twitter Facebook Print License Add us on Google An experimental rare disease drug BioMarin Pharmaceutical purchased through a company acquisition missed one of its two main objectives in a Phase 3 trial, seeding doubt among Wall Street analysts about the therapy’s approval chances. On one hand, the therapy, BMN 401, significantly increased levels of a vital molecule that’s lacking in study participants with that rare condition, ENPP1 deficiency.

But those changes didn’t translate to benefits on an assessment of their skeletal health, a second co-primary study goal. What’s more, “no positive trends” were observed across secondary endpoints, BioMarin said Monday. BioMarin is “actively evaluating” the data to determine the “appropriate next steps,” Greg Friberg, its chief research & development officer, in the company’s statement.

Detailed results will be presented at a future medical meeting. The readout is a setback in BioMarin’s plans to find new sources of revenue. While the company built a multibillion-dollar business out of rare disease drugs, it’s been undergoing a strategic overhaul in recent years under CEO Alexander Hardy, laying off staff, cutting spending and nixing some drug prospects.

Earlier this year, it shelved a once highly-touted hemophilia gene therapy after paltry sales and a failed effort to offload the program. BioMarin’s top seller is now Voxzogo, a treatment for a common form of dwarfism. But even there, BioMarin is facing emerging competition, heightening pressure on the company to diversify.

BioMarin has made a couple acquisitions of late to help. A $4.8 billion buyout of Amicus Therapeutics, for instance, yielded marketed treatments for Fabry and Pompe disease. BioMarin has been hoping a smaller, $270 million purchase of Inozyme would boost its portfolio too.

The latter deal handed BioMarin what’s now known as BMN 401. The treament has been in testing for children with ENPP1 deficiency, a genetic disease in which a shortage of an important molecule called “plasma inorganic pyrophosphate,” or PPi, causes calcium to accumulate in blood vessels and bones. BMN 401 is an enzyme replacement therapy that’s meant to spur production of that molecule.

The company’s Phase 3 trial evaluated the treatment in 27 children with ENPP1 deficiency and who are between 1 to 12 years of age. The study’s initial main goal was to detect a statistically significant increase in PPi levels after a year, a goal BMN 401 achieved. But after discussions with drug regulators, BioMarin added a co-primary objective tied to clinical benefits.

Falling short on that measure, and missing on its secondary trial endpoints, suggest “there’s significant risk to approval,” wrote Stifel analyst Paul Matteis. In a separate note, Leerink analyst Joseph Schwartz also expressed skepticism about BMN 401’s prospects. While ENPP1 deficiency is a “high unmet need medication” and new drugs are needed, “we are cautious on the regulatory path forward at this point,” he wrote.

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