Company · Healthtech & Bio

ARTHEx Biotech

arthexbiotech.com ↗ ·Valencia ·Series B

ARTHEx Biotech is a clinical-stage biotech spin-off from the University of Valencia developing targeted RNA medicines that modulate microRNAs to treat rare genetic neuromuscular diseases. Its lead program, ATX-01, is in Phase I/IIa trials (ArthemiR) for myotonic dystrophy type 1 (DM1) following FDA clearance in 2024. The company closed an upsized $87M Series B in 2025 led by Bpifrance.

Founded

2019

Founders

News

Rounds

Investors

SectorsBiotechnology, RNA therapeutics, Rare disease, Neuromuscular disorders Start-up MapHealthtech & Bio › Drug discovery & therapeutics developers

Profile updated 31 Jul 2026

Founders

Beatriz Llamusí

Chief Scientific Officer & Co-Founder

Rubén Artero

Co-Founder

Global models 5

Skyhawk Therapeutics

United States · www.skyhawktx.com ↗

Develops small-molecule and oligonucleotide RNA-modulating therapeutics for genetic diseases, the same RNA-targeting therapeutic model as ARTHEx.

$181MComparable

Dyne Therapeutics

United States · www.dyne-tx.com ↗

Develops oligonucleotide therapeutics specifically for serious muscle diseases, directly paralleling ARTHEx's neuromuscular RNA medicine focus.

$166MComparable

Avidity Biosciences

United States · www.aviditybiosciences.com ↗

Uses RNA-conjugate therapeutics to target myotonic dystrophy (DM1) and other muscle diseases, the same indication and RNA-modality as ARTHEx's lead program.

$143MComparable

Wave Life Sciences

United States · www.wavelifesciences.com ↗

Develops stereopure oligonucleotide drugs to modulate RNA for genetic diseases, closely matching ARTHEx's oligonucleotide-based therapeutic platform.

$84MComparable

miRagen Therapeutics

United States · www.miragen.com ↗

Developed microRNA-targeted therapeutics, the most direct model match to ARTHEx's anti-miR (antisense microRNA) approach.

$72MComparable

Investors 12

AdBio Partners

adbio.partners ↗

Investor France

Advent Life Sciences

adventls.com ↗

Investor United Kingdom

Bpifrance

Investor France

Columbus Venture Partners

columbusvp.com

Investor Spain

European Innovation Council

eic.ec.europa.eu

Investor Luxembourg

Hadean Ventures

hadeanventures.com ↗

Investor Norway

Invivo Capital

Investor Spain

Sanofi Ventures

www.sanofiventures.com ↗

Investor United States

Sound Bioventures

soundbioventures.com ↗

Investor Sweden

Funding rounds 5

Series B · $87M

ARTHEx Biotech announced it had upsized its Series B to $87M total with new investor Bpifrance (via its Large Venture and InnoBio funds) lea…

2025-09-17

Series B · €42M

Valencia-based clinical-stage biotech ARTHEx closed a €42M Series B led by Columbus Venture Partners to take ATX-01, an antimiR targeting mi…

2023-05-03

Series A · €4.25M

Arthex is a preclinical biotech developing antisense RNA therapies for myotonic dystrophy type 1. Invivo Ventures and Advent France Biotechn…

2020-07-23

Seed · €2.7M

Arthex Biotech is a University of Valencia spin-off developing antisense RNA therapies, starting with myotonic dystrophy type 1. It secured …

2020-07-04

Seed · €1.5M

University of Valencia spin-off Arthex Biotech (reported as 'Arthrex Biotech' in some outlets) closed a €1.5M seed round, the first investme…

2020-01-08

News & media 10

Published	Article
2026-07-23	ARTHEx Biotech Publishes First Demonstration of Improvement in a DM1-related Behavioral Alteration in a Preclinical Model of Myotonic Dystrophy Type 1 (DM1) ↗ Aijourn
2026-05-27	ARTHEx Biotech Delivers Multiple Presentations at IDMC-15 Highlighting Clinical Progress of ATX-01 and Mechanistic Insights for Myotonic Dystrophy Type 1 (DM1) and 2 (DM2) ↗ PR Newswire
2025-09-17	ARTHEx Biotech Upsizes Series B Financing Round to $87M to Advance Lead Program ATX-01 in Myotonic Dystrophy Type 1 and Expand Pipeline of Targeted RNA Medicines ↗ PR Newswire
2024-11-13	ARTHEx Biotech Announces Oral Presentation on ATX-01 at TIDES Europe Annual Meeting 2024 ↗ PR Newswire
2024-11-07	ARTHEx Biotech Announces FDA Rare Pediatric Designation (RPD) of ATX-01 for the Treatment of Myotonic Dystrophy Type 1 (DM1) ↗ PR Newswire
2024-10-18	ARTHEx Biotech Announces First Patient Dosed in Phase I-IIa ArthemiR™ Trial for Myotonic Dystrophy Type 1 (DM1) ↗ PR Newswire
2024-10-15	ARTHEx Biotech Announces Publication of Promising Preclinical Research for Myotonic Dystrophy Type 1 (DM1) ↗ PR Newswire
2024-02-28	ARTHEx Biotech Receives IND Clearance from FDA to Initiate the Phase I-IIa ArthemiR™ Trial of ATX-01 for Myotonic Dystrophy Type 1 (DM1) ↗ BioSpace
2023-10-24	ARTHEx Biotech Announces Sponsorship and Participation in the Spanish Meeting on Oligonucleotide Therapeutics (SMOT III) ↗ BioSpace
2023-05-03	ARTHEx nabs Series B for clinical trial of ASO in myotonic dystrophy as Vertex's deals heat up the space ↗ Endpoints News