Siren Biotechnology Receives FDA Fast Track Designation for SRN-101 to Treat Recurrent High-Grade Glioma

The designation is intended to facilitate the expedited development and review of SRN-101, recognizing its potential to address a serious condition with significant unmet medical need.

Published on Feb. 25, 2026

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Siren Biotechnology, pioneers of Universal AAV Immuno-Gene Therapy for cancer, announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to SRN-101, the company's lead AAV-based immuno-gene therapy for recurrent high-grade glioma (HGG). This designation is intended to facilitate the expedited development and review of SRN-101, recognizing its potential to address a serious condition with significant unmet medical need.

Why it matters

High-grade gliomas, including glioblastoma, are among the most aggressive and lethal primary brain tumors. Current treatments offer limited benefit, and novel therapeutic approaches are urgently needed. The Fast Track Designation for SRN-101 highlights the FDA's recognition of the potential for this therapy to make a meaningful difference for patients facing this devastating disease.

The details

SRN-101 is a recombinant AAV vector expressing an engineered immunomodulatory cytokine designed to locally stimulate a potent anti-tumor immune response within the tumor microenvironment. SRN-101 is built on Siren's Universal AAV Immuno-Gene Therapy platform, a modality that aims to overcome the long-standing limitations of traditional immunotherapy approaches in solid tumors. Siren recently announced FDA clearance of its first Investigational New Drug (IND) filing for SRN-101, enabling first-in-human clinical evaluation in patients with recurrent high-grade glioma.

  • On February 24, 2026, Siren Biotechnology announced that the FDA has granted Fast Track Designation to SRN-101.

The players

Siren Biotechnology

A San Francisco-based biotechnology company that is pioneering Universal AAV Immuno-Gene Therapy, a novel therapeutic modality that combines the precision and durability of AAV gene therapy with the immune-modulating potential of cytokine-based approaches.

Nicole K. Paulk, PhD

The Founder, CEO, and President of Siren Biotechnology.

California Institute for Regenerative Medicine (CIRM)

A state agency created by California voters to accelerate stem cell and gene therapies for people with unmet medical needs.

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What they’re saying

“Fast Track Designation underscores the urgency of bringing new therapeutic options to patients with recurrent high-grade glioma.”

— Nicole K. Paulk, PhD, Founder, CEO, and President of Siren Biotechnology (Siren Biotechnology)

What’s next

Siren Biotechnology plans to initiate first-in-human clinical evaluation of SRN-101 in patients with recurrent high-grade glioma following the FDA's clearance of its Investigational New Drug (IND) filing.

The takeaway

The FDA's Fast Track Designation for Siren Biotechnology's SRN-101 highlights the urgent need for new and more effective treatments for recurrent high-grade glioma, one of the most aggressive and deadly forms of brain cancer. This designation underscores the potential of Siren's Universal AAV Immuno-Gene Therapy platform to address this significant unmet medical need.