BioArctic and Mesenkia enter oncology research collaboration

Stockholm, Sweden, August 19, 2026 – BioArctic AB (publ) (Nasdaq Stockholm: BIOA B) and Mesenkia Therapeuticsannounced today that the companies have signed a research collaboration agreement to explore a novel antibody-based approach for glioblastoma, one of the most aggressive and treatment-resistant forms of brain cancer, where effective delivery of large molecules to the brain remains a major challenge.

The collaboration combines BioArctic’s proprietary BrainTransporter™ technology with an antibody, developed with Mesenkia’s KITAIbodies® platform. The antibody targets HVEM[1], a protein found on the surface of certain glioblastoma tumor cells, including tumor stem cells. By addressing these cells, which are thought to contribute to tumor recurrence and treatment resistance, the project aims to unlock new treatment possibilities for patients with a very high unmet medical need.

Under the agreement, BioArctic will be responsible for generating a novel drug candidate by combining its BrainTransporter technology with Mesenkia’s antibody. BioArctic and Mesenkia thereafter plan to perform preclinical studies to validate the concept and, based on the results of these studies, decide on next steps.

This research collaboration represents an important step in expanding BioArctic’s BrainTransporter pipeline into oncology and further validates the platform’s potential beyond neurodegenerative diseases. It also builds on BioArctic’s core expertise in development and delivery of pharmaceuticals to the brain.

“We are excited to broaden our research and take a first step into oncology through this collaboration,” said Gunilla Osswald, Chief Executive Officer of BioArctic. “Glioblastoma remains one of the most challenging cancers to treat, with limited therapeutic options and poor prognosis for those affected. By combining our BrainTransporter technology with Mesenkia’s innovative antibody approach, we aim to target key disease-driving mechanisms to develop new ways to treat this devastating disease.”

“This agreement marks an important step for Mesenkia and creates clear opportunities to explore a new treatment strategy for patients with glioblastoma together with BioArctic. The need for new treatments is substantial, particularly given the challenge of delivering medicines to tumor cells throughout the brain. By combining Mesenkia’s antibody expertise with BioArctic’s BrainTransporter technology, we can address one of the disease’s key barriers in a new way. We look forward to advancing the concept together with BioArctic, with the long-term goal of enabling better treatment options for patients and their loved ones,” said Moa Fransson, Chief Executive Officer of Mesenkia.

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The information was released for public disclosure, through the agency of the contact person below, on August 19, 2026, at 11:15 am CET.
For further information, please contact:
BioArctic

Oskar Bosson, Chief Investor Relations & Communications Officer

E-mail: oskar.bosson@bioarctic.com

Telephone: +46 704 107 180
Jenny Ljunggren, External Communications and Investor Relations Manager

E-mail: jenny.ljunggren@bioarctic.com

Telephone: +46 76 013 86 08

Mesenkia

Moa Fransson, CEO

E-mail: moa.fransson@mesenkia.com

Telephone: +46 072 211 71 61

About Mesenkia Therapeutics AB

Mesenkia is a pre-clinical company developing the next-generation biological drug candidates designed to treat the aggressive brain tumor glioblastoma. Mesenkia is founded on world leading science from Uppsala University and the University of Tokyo originating from decades of collaborations dedicated to finding the root cause for tumor pathogenesis. The company’s lead program targets glioblastoma, while their KITAIbodies® are designed to enable future therapeutics across multiple indications and modalities. Through strategic collaborations with pharmaceutical companies, Mesenkia aims to accelerate drug development and create value for patients worldwide.

About BioArctic AB
BioArctic AB (publ) is a Swedish research-based biopharma company focusing on innovative treatments that can delay or stop the progression of neurodegenerative diseases. The company invented Leqembi® (lecanemab) – the world's first drug proven to slow the progression of the disease and reduce cognitive impairment in early Alzheimer's disease. Leqembi has been developed together with BioArctic’s partner Eisai, who are responsible for regulatory interactions and commercialization globally. In addition to Leqembi, BioArctic has a broad research portfolio with antibodies against Parkinson's disease and ALS as well as additional projects against Alzheimer's disease. Several of the projects utilize the company's proprietary BrainTransporter™ technology, which has the potential to actively transport antibodies across the blood-brain barrier to enhance the efficacy of the treatment. BioArctic's B share (BIOA B) is listed on Nasdaq Stockholm Large Cap. For further information, please visit www.bioarctic.com.