• Survival Advantage: Mice treated with Zeta-BC-007 survived beyond 60 days, unlike those receiving Tamoxifen (TAM) or Abemaciclib (ABE)
• Tumor Reduction: Zeta-BC-007 combinations reduced tumor volume by up to 66%, compared to 34% (TAM) and 15% (ABE)
• Synergistic Cytotoxicity: NaN and ABE together decreased cell proliferation by 60% in vitro, suggesting synergistic effects
• No Tumor Activity: Histology revealed no ki67 staining and increased necrosis in Zeta-BC-007-treated tumors
• Immune Activation: Treated mice showed elevated macrophage infiltration and increased circulating monocytes

Zetagen Therapeutics, a privately held clinical-stage biopharmaceutical company pioneering first-of-its-kind targeted therapies for both primary and metastatic breast cancer, announced today that its abstract titled “Increased Survival in Nude Mice Inoculated with MCF7 Breast Cancer (BC) in the Mammary Fat-Pad Achieved via a Single Injection of a Lipid-like Hydrogel Emulsion Containing a New Molecular Entity (NME) and N-ally Noroxymorphone (NaN) Compared to Tamoxifen (TAM) and Abemaciclib (ABE)”, has been accepted and will be presented at the 2025 San Antonio Breast Cancer Symposium (SABCS) on Thursday, December 11, 2025.

In a head-to-head comparison with standard-of-care therapies Tamoxifen and Abemaciclib (i.e., Verzenio), a single intratumoral injection of Zeta-BC-007 significantly outperformed both agents. Mice treated with Zeta-BC-007 containing NME + NaN + ABE showed a 66% reduction in tumor volume and complete absence of tumor activity by day 60, while all mice in the TAM and ABE groups succumbed to disease.

“Zeta-BC-007 represents a significant leap forward in intratumoral cancer therapy. By combining a novel molecular entity with synergistic therapeutics in a lipid-based hydrogel, we’ve demonstrated not only superior tumoricidal activity but also extended survival in preclinical models. These results reinforce our commitment to developing localized, non-systemic treatments that challenge the limitations of conventional cancer care.”

— Bryan S. Margulies, PhD, Co-founder and CSO, Zetagen Therapeutics

“These results mark a pivotal moment in our journey to redefine primary breast cancer treatment,” said Joe C. Loy, CEO of Zetagen Therapeutics. “the ability of Zeta-BC-007 to deliver potent tumoricidal effects through a single localized injection — without systemic toxicity — represents a new frontier in oncology. We believe this platform has the potential to transform how solid tumors are treated.”

Presentation Details:

• Abstract Number: 3638
• Presentation Number: PSA-06-30
• Presentation Title: Increased Survival in Nude Mice Inoculated with MCF7 Breast Cancer (BC) in the Mammary Fat-Pad Achieved via a Single Injection of a Lipid-like Hydrogel Emulsion Containing a New Molecular Entity (NME) and N-ally Noroxymorphone (NaN) Compared to Tamoxifen (TAM) and Abemaciclib (ABE)
• Poster Presentation: Thursday, December 11, 2025, 5:00-6:30pm CST

About ZetaPrime™ (Zeta-PBC-007)

ZetaPrime™ is a neo-adjuvant treatment for primary HR+ breast cancer, engineered for a locoregional administration following diagnosis. Utilizing a proprietary hydrogel-like lipid carrier, the novel formulation enables controlled release of multiple small molecules — with one being our novel molecular entity coupled with any other fat-soluble drugs; including other companies CDK4 or CDK4/6 protein inhibitors or any anticancer therapeutic. Designed for solubility within adipose tissue, ZetaPrime™ is a paradigm-shifting intratumoral approach to adjuvant therapy that targets primary breast cancer, aiming to mitigate off-target effects, reduce necessity for lumpectomies and mastectomies, postpone radiation exposure, and enhance patient survival.

About Zetagen Therapeutics

Zetagen has three novel drugs in development with the Zeta Platform, ZetaMet™ (Zeta-BC-003), for the treatment of metastatic breast cancer to bone, ZetaMast™ (Zeta-MBC-005) for breast cancer liver metastases (BCLM), and ZetaPrime™ (Zeta-PBC-007) for the treatment of primary HR+ breast cancer, all with inspiring results. To learn more, visit www.zetagen.com. The entire Zeta platform is designed for intratumoral administration to reduce off-target toxicity, utilizing proprietary carriers—some incorporating our New Molecular Entity. The USPTO has granted Zetagen Composition-of-Matter patents and claims for all three therapeutics.

Zetagen Upcoming Events

Zetagen will attend the 2025 San Antonio Breast Cancer Symposium (SABCS) and the 2026 JP Morgan Healthcare Conference.

Forward-Looking Statements

This press release contains certain forward-looking statements with the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and Private Securities Litigation Reform Act, as amended, including those relating to the Company’s product development, clinical and regulatory timelines, market opportunity, competitive position, possible or assumed future results of operations, business strategies, potential growth opportunities and other statements that are predictive in nature. These forward-looking statements are based on current expectations, estimates, forecasts and projections about the industry and markets in which we operate and management’s current beliefs and assumptions. Source: Zetagen Therapeutics, Inc.

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