BioMarin to Buy Rare Bone Disease-Focused Alesta for up to $490 Million

Rare Daily Staff

BioMarin Pharmaceutical said it will acquire Alesta Therapeutics in a deal worth up to $490 million, gaining rights to an experimental oral medicine for hypophosphatasia, a rare inherited disease that can cause fragile bones, tooth loss, pain and muscle weakness.

BioMarin will pay $275 million upfront and could pay up to an additional $215 million if the drug, known as ALE1, meets specified development and regulatory milestones. The transaction is expected to close this quarter, subject to customary conditions.

Before the acquisition is completed, Alesta will separate its non-ALE1 assets into a newly created company. Its employees will transfer to that spinout, and no Alesta staff members are expected to join BioMarin as part of the transaction.

For BioMarin, the acquisition adds an early-stage program to its rare-disease pipeline and offers a potential entry into a larger patient population than some of the company’s existing markets.

“This is exactly the kind of opportunity to address a significant unmet need,” BioMarin CEO Alexander Hardy said in a statement, describing ALE1 as a potential oral alternative to currently available injectable therapies.

ALE1 is being tested in an early phase 1/2a study involving healthy volunteers and adults with hypophosphatasia, or HPP. The drug has not been approved, and its safety and effectiveness have yet to be established.

Hypophosphatasia is caused by mutations in the ALPL gene, which can disrupt normal mineralization of bones and teeth. Symptoms vary widely, but people with the condition can experience frequent fractures, premature tooth loss, fatigue, muscle weakness and chronic pain. More than 9,000 people in the United States have been diagnosed with HPP, although the company said the disorder may be underdiagnosed because its symptoms can resemble those of more common bone and musculoskeletal conditions.

ALE1 is a small-molecule medicine designed to reduce excess levels of inorganic pyrophosphate, or PPi, a substance implicated in the disease’s biology. The goal is to restore healthier bone mineral metabolism throughout the body.

If successful in later testing and approved by regulators, ALE1 could become the first oral treatment for HPP. Current treatment options include injectable therapies, potentially making an oral medicine more convenient for some patients.

The drug will join BioMarin’s Skeletal Conditions Business Unit after the deal closes. The San Rafael-based company said it will fund the acquisition with cash on hand and expects the deal, excluding the upfront payment, to have a modestly dilutive effect on its 2026 financial results.

Photo: BioMarin CEO Alexander Hardy