Spanish company ARTHEx Biotech raises $87 million in Series B extension

Spanish company ARTHEx Biotech, a spin-off from the University of Valencia developing targeted RNA medicines for rare neuromuscular disorders, has raised $87 million in an extension of its Series B funding round. The round was led by Bpifrance, through its Large Venture and InnoBio strategies, with participation from existing shareholders including AdBio Partners, CDTI Innovación, Columbus Venture Partners, the European Innovation Council (EIC), Hadean Ventures, Invivo Partners and Sound Bioventures.

The investment will help the Spanish company advance its main drug candidate for myotonic dystrophy type 1 (DM1) and continue building a broader portfolio of RNA-based treatments for conditions affecting the muscles, brain and heart. Regulators in both the U.S. and Europe have already granted the lead program “orphan drug” status, which is intended to support treatments for rare diseases. Initial results from patient studies are expected in 2026.

Bpifrance was advised on the investment by Bird & Bird, whose cross-border team included partner Lourdes Ayala, counsel Antonio Ballesteros, and associate Adrian Bert, from Bird & Bird Spain, and partner Carole Bodin and associate Jasmine Javault, from Bird & Bird France.