
Ysios Capital
Avenida de la Libertad, 25 4th floor, Donostia-San Sebastián, Pais Vasco, 20004, Spain
Overview
Ysios Capital is a leading Spanish independent venture capital firm that provides private equity financing to early and mid-stage life science companies that develop disruptive therapeutic products and platform technologies. Founded in 2008, Ysios Capital manages c.a. €350 M through three dedicated funds in life sciences and is led by a team of professionals experienced in building biotech companies.
- Total investments
- 66
- Lead investments
- 18
- Investments · 12mo
- 3
- Active investors
- 9
Sector focus
- Asset Management
- Finance
- Financial Services
Investment portfolio
- Kynexis
Participated · Series A · Aug 2026
Kynexis is developing KYN-5356, a potential first-in-class oral small-molecule inhibitor of KAT-II intended to reduce brain kynurenic acid (KYNA) and restore signaling involved in cognition. The company’s initial clinical focus is cognitive impairment associated with schizophrenia (CIAS), with plans to expand into other cognitive disorders including Alzheimer’s disease. KYN-5356 is the company’s most advanced program and has demonstrated favorable safety, central nervous system penetration, and dose-dependent reductions in cerebrospinal fluid KYNA in Phase 1. Kynexis has completed enrollment in a randomized, double-blind, placebo-controlled Phase 2 trial of ~150 adults across 13 U.S. sites evaluating a 28-day adjunctive treatment and expects topline results by the end of 2026. The company has a U.S. subsidiary based in Cambridge, Massachusetts, and recently added senior business development leadership to support its clinical and corporate strategy.
- Ona Therapeutics
Participated · Series B · Jun 2026
Ona Therapeutics is a spin-off from IRB Barcelona and ICREA that develops precision-engineered antibody-drug conjugates (ADCs) to target treatment-resistant cancers. The company uses a proprietary, patient-driven discovery platform to identify tumor-specific antigens and epitopes that enable efficient internalization and targeted payload delivery. Its lead clinical program is ONA-255, initially focused on breast cancer, and it is also advancing ONA-389 targeting colorectal cancer. The company integrates target validation, antibody engineering, optimized payload selection and validated linker-payload technologies in its ADC development approach. Led by CEO Valerie Vanhooren, Ona plans to use the Series B proceeds to advance clinical development of its lead and second programs. The article does not disclose revenue, user metrics or a company valuation.
- ADCendo
Participated · Series C · Apr 2026
Adcendo is advancing a pipeline of first- and potential best-in-class antibody-drug conjugates, integrating novel targets and optimized linker-payload combinations. The company is progressing three ADC programs: ADCE-T02 (Tissue Factor) in a Phase I Tiffany-01 cohort expansion across multiple solid tumors, ADCE-D01 (uPARAP) in Phase 1 dose escalation and expansion for soft tissue sarcoma and other mesenchymal cancers, and ADCE-B05 (undisclosed target) in preclinical evaluation and planned dose escalation in squamous cell carcinomas. Founded in 2017, Adcendo is headquartered in Copenhagen with operations in Boston, Massachusetts, and is led by a team with extensive ADC development and commercialization experience. The recent $75 million Series C financing is intended to fund the programs through upcoming clinical milestones and data readouts. No revenue or other operating metrics were disclosed in the provided articles.
- Splice Bio
Participated · Series B · Jun 2025
SpliceBio is a clinical-stage genetic medicines company pioneering a Protein Splicing platform that uses engineered inteins to enable delivery of large genes via dual AAV vectors. Its lead program, SB-007, is a dual AAV gene therapy designed to restore full-length ABCA4 protein expression for Stargardt disease. SB-007 received FDA IND clearance in December 2024, has Orphan Drug Designation from both the FDA and the European Commission, and obtained MHRA clearance to enter clinical development. The company is currently running the Phase 1/2 ASTRA interventional study (first patient dosed March 2025) and the POLARIS observational natural history study. Proceeds from the financing will support continued clinical development of SB-007 and accelerate SpliceBio's broader pipeline of AAV gene therapy programs in ophthalmology, neurology, and other undisclosed indications. SpliceBio leverages technology developed in the Muir Lab at Princeton University and is based in Barcelona, Spain. SpliceBio exploits Protein Splicing to develop the next generation of gene therapies and operates a proprietary platform that enables efficient delivery of large genes with adeno-associated vectors (AAV). The platform is designed to overcome AAV cargo-size limits by using intein and protein engineering approaches developed over more than 20 years in the Muir Lab at Princeton University. Led by CEO Miquel Vila-Perelló, the company intends to use its technology to build a pipeline of Protein Splicing gene therapy programs. Its lead program in Stargardt disease is being advanced toward the clinic. Financially, SpliceBio raised €50M in a Series A financing to support pipeline development and clinical advancement. The company was seeded in 2020 by Ysios Capital and Asabys Partners. Splice Bio, formerly ProteoDesign, develops intein-based technologies for gene therapy aimed at treating genetic diseases. Its platform, based on research carried out at Princeton by the company's cofounders, is designed to overcome key limitations of adeno-associated viral (AAV) vectors. The technology could enable treatments for diseases caused by mutations in large genes and broaden the range of organs that can be targeted. The company announced a new financing round to advance the development of these therapies. Proceeds will be used to develop new therapies for genetic diseases. Splice Bio also refreshed its brand to reflect its renewed focus on gene therapy. ProteoDesign is a biotechnology spin-out from Princeton University that develops personalized cancer immunotherapies. The company says it has a novel in-house protein-engineering platform discovered after more than 20 years of pioneering research. ProteoDesign announced the close of a €1.7 million funding round led by venture firm Caixa Capital Risc, with participation from a business angel. Caixa Capital Risc was already an existing investor in the company's shareholder base. The proceeds will be used to advance ProteoDesign's immunotherapy candidates through preclinical development.
- ReproNovo
Participated · Series A · May 2025
ReproNovo is a biopharmaceutical company focused on developing treatments for reproductive medicine and women’s health. Its lead clinical compound, RPN-001 (leflutrozole), is being developed to treat male infertility, while RPN-002 (nolasiban) is designed to manage adenomyosis and improve embryo implantation in ART. Both assets are Phase 2 ready. The company intends to use the Series A proceeds to advance a pipeline of multiple Phase 2 programs. ReproNovo is led by CEO Jean Marie Duvall, CSO & CMO Joan‑Carles Arce, MD, PhD, and CFO BingMei Hao. It maintains a primary development team in Copenhagen and an additional development site in Barcelona, with corporate base in Lausanne, Switzerland.