FDA Grants Fast Track Designation to SRN-101 for Recurrent High-Grade Glioma

The FDA has granted fast track designation to SRN-101 for the treatment of patients with recurrent high-grade glioma, according to a news release from the developer, Siren Biotechnology.¹ The regulatory milestone follows the recent FDA clearance of the company’s first investigational new drug application, which allows for the initiation of the first-in-human clinical evaluation of the agent in this patient population.² SRN-101 is an adeno-associated virus (AAV)-based immuno-gene therapy designed to deliver therapeutic effects directly to the tumor microenvironment.

SRN-101 utilizes a recombinant AAV vector to express an engineered immunomodulatory cytokine. This approach is designed to locally stimulate a potent anti-tumor immune response within the tumor microenvironment, potentially overcoming the historical limitations of traditional immunotherapy in solid tumors. The agent is the lead candidate built on the Universal AAV Immuno-Gene Therapy platform, a modality that combines gene therapy with the immune-modulating potential of cytokines.

The development of SRN-101 is intended to address the significant unmet medical need in high-grade gliomas, including glioblastoma, which are characterized by high levels of aggression and lethality. Current standards of care, including surgical intervention, radiation, and chemotherapy, often provide limited benefits for patients with recurrent disease. By providing localized and sustained immune activation, the developer aims to establish a new therapeutic model for treating aggressive primary brain tumors.

“Fast track designation underscores the urgency of bringing new therapeutic options to patients with recurrent high-grade glioma,” stated Nicole K. Paulk, PhD, founder, chief executive officer, and president of Siren Biotechnology. “We believe SRN-101 represents a fundamentally new approach to treating solid tumors, and this designation reinforces the FDA’s recognition of its potential to make a meaningful difference for patients facing this devastating disease.”

Following IND clearance, SRN-101 will enter its first phase of clinical evaluation in patients with recurrent high-grade glioma. The trial is designed to evaluate the safety and preliminary activity of the AAV-based immuno-gene therapy. The research and development of the program have been supported in part by the California Institute for Regenerative Medicine through a TRAN1-15325 grant.

The upcoming clinical evaluation will serve as the first-in-human study to characterize the safety and tolerability of SRN-101. As the agent is designed for localized delivery within the tumor microenvironment, the trial will monitor for potential adverse events related to the AAV vector and the expression of the engineered cytokine.

Previous to the investigational new drug clearance, the FDA also granted SRN-001 the orphan drug designation and the rare pediatric disease designation for patients with high-grade gliomas and pediatric-type diffuse high-grade gliomas, respectively.³ In that release, Nicholas Butowski, MD, a neuro-oncologist and director of Translational Research in Neuro-Oncology at the University of California, San Francisco, said, “SRN-101 has the potential to address a critical gap in effective high-grade glioma therapies by leveraging the body’s immune response in a targeted, innovative way. This approach could represent a major breakthrough in how we treat one of the most devastating brain cancers and offers a new path of hope for patients.” They also reported that SRN-001 exhibited potent antitumor effects in preclinical models of brain cancer.

References

1. Siren Biotechnology receives FDA Fast Track Designation for SRN-101 for the treatment of recurrent high-grade glioma. News release. Siren Biotechnology. February 24, 2026. Accessed February 25, 2026. https://tinyurl.com/mu8z7csx
2. Siren Biotechnology announces FDA clearance of first IND, advancing company to clinical stage. News release. Siren Biotechnology. January 28, 2026. Accessed February 25, 2026. https://tinyurl.com/2y3b3as9
3. Siren Biotechnology reveals SRN-101 as lead asset for high-grade gliomas with both orphan drug and rare pediatric disease designations from the FDA. News release. Siren Biotechnology. November 18, 2024. Accessed February 25, 2026. https://tinyurl.com/mwzmwu59