BlueSky Immunotherapies Reports Positive Interim Results from Phase 1 Trial of delNS
Viral Vector Therapy for HPV-Positive OPSCC

Vienna, April 2026 – Independent Data Monitoring Committee Approves Continued Enrollment Following Strong Safety and Immune Activation

BlueSky Immunotherapies today announced encouraging interim results from its ongoing Phase 1 clinical trial evaluating the company’s innovative delNS viral vector platform in patients with HPV-positive Oropharyngeal Squamous Cell Carcinoma (OPSCC). The first patient cohort of four individuals has successfully completed treatment in the neoadjuvant study, marking another important milestone in the clinical development of this novel immunotherapy.

Following completion of treatment in the first cohort, an independent Data Monitoring Committee (DMC) reviewed the available clinical and translational data and confirmed an excellent safety profile, approving continuation of the study and treatment of the remaining eight patients planned for the Phase 1 trial.

Importantly, detailed analysis of tumor samples demonstrated strong immune activation within the tumor microenvironment, including substantial infiltration of T-cells and macrophages following treatment. Such immune infiltration is widely recognized as a key biological marker associated with improved anti-tumor responses and enhanced overall survival across multiple cancer types.

HPV-positive OPSCC remains one of the fastest-rising cancers in the Western world, highlighting the urgent need for innovative therapeutic approaches. BlueSky’s delNS viral vector technology is designed to stimulate robust interferon signaling while delivering the HPV-derived E6 and E7 tumor antigens, enabling the immune system to recognize and attack HPV-driven cancer cells and overcome the immunosuppressive tumor environment characteristic of this disease.

In this ongoing neoadjuvant clinical trial, patients receive an initial intratumoral administration of the delNS/E6E7 vector prior to surgery and/or radiotherapy, followed by additional systemic immunization. The goal of this approach is to prime a strong tumor-specific  immune response before removal of the tumor, potentially improving long-term disease control.

“These interim results are extremely encouraging,” said Dr. Thomas Muster, Chief Executive Officer of BlueSky Immunotherapies. “The independent Data Monitoring Committee’s decision to approve continuation of the trial underscores the excellent safety profile of our delNS vector platform. Equally important is the robust immune cell infiltration we observe in treated tumors, indicating that the therapy successfully activates the immune system against HPV-driven cancer.”

Dr. Muster added: “This builds on our previous clinical successes with the delNS platform and strengthens our confidence that this approach could represent a powerful new immunotherapy strategy for HPV-associated cancers.”

BlueSky Immunotherapies continues to collaborate with leading oncology centers to further evaluate the clinical potential of the delNS platform. The company plans to complete enrollment in the current Phase 1 trial and further advance clinical development to confirm therapeutic benefit in larger patient populations.

For more information about BlueSky Immunotherapies and its innovative immunotherapy platform, please visit www.bluesky-itx.com.

About BlueSky Immunotherapies

BlueSky Immunotherapies is a biotechnology company dedicated to developing next-generation immunotherapies for cancer treatment. Leveraging its proprietary delNS viral vector technology, the company aims to harness the immune system to recognize and eliminate cancer cells, addressing major unmet medical needs in oncology.

For media inquiries, please contact: Michael Tscheppe, BlueSky Immunotherapies, m.tscheppe@bluesky-itx.com

Forward-Looking Statements

This press release may contain forward-looking statements subject to applicable European Union regulations and Austrian financial disclosure laws. These statements involve risks and uncertainties that could cause actual results to differ materially from those projected or anticipated. BlueSky Immunotherapies assumes no obligation to update these statements except as required by law.