Zetagen Therapeutics Closes Oversubscribed Series B1 Round on Strength of Promising Phase 2a Data and Compelling Pipeline 

• The funding round closed with strong demand from private investors—led by JSTAR Capital Investments—demonstrating deep confidence in our clinical efficacy. 

November 25, 2025, (Syracuse, New York) — Zetagen Therapeutics, Inc., a privately held, clinical-stage biopharmaceutical company pioneering first-of-its-kind, intratumoral treatments for metastatic and primary breast cancer, today announced the successful closure of its Series B1 financing round of $12,908,000. The round was 100% oversubscribed, reflecting strong investor confidence in the company’s proprietary Zeta Platform and its potential to transform breast cancer care. 

Proceeds from this round will support the advancement of Zetagen’s lead candidate, ZetaMet™ (Zeta-BC-003) towards commercialization, accelerate clinical development of ZetaMast™ (Zeta-MBC-005), and complete preclinical studies & GMP manufacturing of ZetaPrime™ (Zeta-PBC-007). 

“The strong demand in our Series B1 round highlights the promise of our Phase 2a clinical data for ZetaMet in treating metastatic breast cancer to bone,” said Joe C. Loy, CEO of Zetagen Therapeutics. “At the core of these encouraging results is our discovery of a novel molecular pathway—triggered by our compounds activating a conserved nuclear receptor—which enables promising predictability in dosing and outcomes from bench to bedside.” 

Advancing the Zeta Platform 

Zetagen’s Zeta Platform is the development of first-of-its-kind therapies for metastatic and primary breast cancer. Our novel approach via proprietary carriers with a singular injection, delivers tumoricidal compounds which minimize severe off-target side effects while increasing survival rates. 

The platform includes: 

• ZetaMet™ (Zeta-BC-003): Targets metastatic breast cancer in bone, ceasing lytic activity, inhibiting pain, and regenerating new bone, all via a singular intratumoral injection, without systemic limitation, minimizing skeletal related events (fractures). We have completed a Phase 2a clinical trial at the University of British Columbia demonstrated Complete Response in treated lesions, full bone regeneration, and no skeletal-related events. Preliminary results to be presented at the upcoming SABCS conference. 
• ZetaMast™ (Zeta-MBC-005): is a novel hydrogel delivering two synergistic tumoricidal agents via a single intratumoral injection for breast cancer liver metastases (BCLM). Designed to localize treatment and reduce systemic toxicity, it has shown promising preclinical results—published in PLOS ONE and co-authored by Dr. Debu Tripathy—demonstrating reduced tumor burden, prevention of soft tissue metastases, and improved survival. A Phase 1b dose-escalation study is planned for 1H-2026. 
• ZetaPrime™ (Zeta-PBC-007): a neo-adjuvant treatment engineered for intratumoral administration following diagnosis. Utilizing proprietary hydrogel-like lipid carrier, formulation enables controlled release of 2 small molecules—one being novel molecular entity and or the ability to deliver a CDK4 or CDK4/6 protein inhibitor. Designed for solubility within adipose tissue, approach targets primary breast cancer, aiming to mitigate off-target effects, potentially reducing necessity for lumpectomies and mastectomies, decrease radiation exposure, and enhance patient survival. ZetaPrime’s single-dose in-vivo study showed improved survival and tumor suppression over Tamoxifen and Verzenio in a mouse mammary fat pad model; results will be presented at the upcoming SABCS conference. 

Continued Momentum 

The Series B1 funding follows a series of strategic milestones for Zetagen, including: 

• Expansion of the company’s global IP portfolio to 70+issued patents including Composition-of-Matter patents & claims on ZetaMet™, ZetaMast™, and ZetaPrime™ 
• Successful completion of the Phase 2a study of ZetaMet™ for metastatic breast cancer to bone 
• Accepted abstracts by SABCS on ZetaMet™ preliminary clinical results and ZetaPrime™ in-vivo results of head-to-head comparison towards Verzenio 

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