BioMarin Pharmaceutical Inc. agreed to acquire clinical-stage biotech Alesta Therapeutics for up to $490 million, the company said on Wednesday.
The deal includes an immediate cash payment of $275 million for Alesta’s lead asset, ALE1, an oral small-molecule therapy in development for hypophosphatasia, a rare inherited disorder that impairs bone and tooth mineralization. BioMarin may also pay up to $215 million in additional milestone-based payments tied to regulatory and commercial progress.
The transaction is slated to close in the third quarter of 2026, subject to customary closing conditions. Prior to completion, Alesta will spin off all non-ALE1 assets into a separate entity, with existing shareholders—including RTW Biotech Opportunities Ltd—retaining their proportional ownership in the new company.
RTW Biotech Opportunities Ltd, which invested in Alesta through a Series A round in December 2024 and a follow-on in September 2025, disclosed that the upfront payment represents a 41% increase on its carrying value of Alesta as of July 31, 2026. RTW’s holding in Alesta was valued at $3.8 million at that time, equivalent to 0.4% of its net asset value.
Hypophosphatasia can lead to fractures, tooth loss, muscle weakness, fatigue, and chronic pain. ALE1 is designed to address the underlying metabolic deficiency associated with the condition. BioMarin did not disclose further financial terms or integration plans beyond the upfront and milestone payments.
