LONDON: BioMarin Pharmaceutical Inc. has agreed to acquire Alesta Therapeutics, a clinical-stage biotechnology company, in a deal that could be worth up to $490 million, the companies announced Wednesday.
The acquisition gives BioMarin control of ALE1, Alesta’s lead experimental drug candidate for hypophosphatasia, a rare inherited disorder that impairs bone and tooth mineralization and can cause fractures, muscle weakness and chronic pain.
Under the terms of the agreement, BioMarin will pay $275 million in upfront cash, with an additional $215 million possible upon the achievement of certain developmental and regulatory milestones. The transaction is expected to close in the third quarter of 2026.
The upfront payment represents a 41% premium to the carrying value of Alesta as of July 31, according to RTW Biotech Opportunities Ltd., an investment firm that holds a stake in Alesta.
Before the deal closes, Alesta will spin out all non-ALE1 assets into a newly created entity. Existing Alesta shareholders, including RTW Bio, will retain their pro rata interest in the new company.
RTW Bio first invested in Alesta during its Series A financing round in December 2024 and again in September 2025, investing a total of 2.4 million euros. As of July 31, RTW Bio’s holding in Alesta was valued at $3.8 million, representing 0.4% of the firm’s net asset value. The company said the upfront payment would add an estimated $1.6 million to its July 31 NAV.
Rod Wong, CIO of RTW Investments, said, “We backed Alesta at Series A because of the differentiated profile of ALE1, supported by a management team with a strong track record in rare disease drug development. BioMarin’s decision to acquire the company at pre-Phase 2 data is a clear validation of our strategy of identifying and supporting differentiated science at the earliest stages of the private markets, where the greatest value can be created for our shareholders. This is the sixth acquisition from our portfolio announced this year and reflects continued strategic appetite from large-cap pharma facing a cumulative $170 billion patent cliff by 2032. We expect the current pace of dealmaking to persist, and RTW Bio remains well positioned across both its public and private portfolios to benefit.”
The acquisition marks the sixth portfolio company transaction for RTW Bio in 2026, following recent acquisitions by Boston Scientific, GSK, Biogen, Eli Lilly and AbbVie.
