At the 2025 Annual Meeting of the American Association for the Study of Liver Diseases (AASLD), CureGene unveiled groundbreaking preclinical results for CG-1999, its independently developed hepatitis B therapeutic vaccine. The findings were presented in a poster session and at a special symposium. The data demonstrate that CG-1999, through a unique immunomodulatory mechanism, activates virus-specific immune responses and achieves sustained clearance of multiple viral markers after treatment cessation in animal models when used in combination therapy. This represents a remarkably new strategy for achieving functional cure of hepatitis B.
Addressing the Core Challenge of Hepatitis B Cure: From Viral Suppression to Immune Reactivation
Current hepatitis B treatments still struggle to achieve functional cure, particularly sustained serological response defined by HBsAg levels (to below the lower limit of detection). The root cause lies in the immune exhaustion state that develops in patients. Unlike direct-acting antivirals or HBsAg-suppressing agents, CG-1999 does not directly target the virus. Instead, it precisely stimulates and modulates the host immune system, reverses T-cell exhaustion, and restores the immune system’s ability to actively eliminate virus-infected cells. This approach fundamentally breaks through immune exhaustion barriers to enable functional cure.
The results presented at AASLD 2025 show that combination regimens incorporating CG-1999 produce profound and durable immune recovery and serological responses in AAV-HBV and HBV transgenic mouse models. Key findings include:
- Sustained HBsAg serological response and intrahepatic viral antigen clearance: Under combination therapy, CG-1999 drives HBsAg levels below the lower limit of detection, with the effect sustained for 10 weeks after treatment cessation and no viral rebound, meeting clinical criteria for functional cure.
- Induction of specific T-cell immune responses: The studies confirm that CG-1999 effectively reverses T-cell exhaustion and induces the production of abundant HBV-specific T cells and multifunctional effector T cells (IFN-γ+, TNF-α+, IL-2+, T-Cell, etc.), the direct "immune weapons" for viral clearance.
- Efficient activation of human-derived CD8+ T cells: In vitro studies using human immune cells from diverse genetic backgrounds prove that CG-1999 effectively activates broad HBV-specific CD8+ T-cell responses and induces expression of multiple effector cytokines. This finding provides solid support for its universal efficacy in humans.
Significant Combination Therapy Potential Reshaping the Clinical Cure Landscape
CG-1999 demonstrates strong synergistic effects when used in combination with existing agents such as nucleoside antiviral drugs or small nucleic acid drugs. These combination regimens not only achieve deep reductions in virological markers but also successfully elicit high-level of HBs antibodies (HBsAb), providing dual protection for establishing durable viral control. This underscores that a "direct antiviral + immunomodulation" combination strategy represents a feasible path toward functional cure.
The groundbreaking CG-1999 data presented by CureGene not only mark progress for a single drug candidate but also demonstrate the potential to fundamentally transform the treatment paradigm for chronic hepatitis B through immune modulation. The unique mechanism of action brings new hope to more than 250 million people living with chronic hepatitis B worldwide.
About Functional Cure of Chronic Hepatitis B
More than 250 million people worldwide are chronically infected with hepatitis B virus (HBV), facing elevated long-term risks of liver cirrhosis and HCC (liver cancer). Although existing nucleoside drugs and interferons can effectively suppress viral replication, very few patients achieve HBsAg clearance—the definition of "functional cure". Achieving functional cure means that patients maintain a sustained virological response after treatment cessation, with persistent serological for HBsAg, alleviated liver inflammation, and significantly reduced long-term risk of HCC. It is regarded as the most clinically meaningful goal in current hepatitis B treatment and a core focus of global research efforts.
About CG-1999
CG-1999 is a novel immunomodulator (mRNA therapeutic vaccine) independently developed by CureGene with an entirely new mechanism of action. It specifically activates patients’ own HBV-specific T-cell immune responses through an innovative mechanism, reverses immune exhaustion, and fundamentally breaks immune barriers, offering a new approach to solving the core challenge of functional cure for hepatitis B. Preclinical studies show that CG-1999, when used in combination therapy, achieves sustained suppression of HBV infection with durable efficacy after treatment cessation, demonstrating strong clinical translational potential. It is expected to play a key role in achieving functional cure of hepatitis B, bringing new hope to hundreds of millions of chronic hepatitis B patients worldwide.
About AASLD
The American Association for the Study of Liver Diseases (AASLD) is the most authoritative professional organization in the global field of hepatology, dedicated to advancing excellence in liver disease research, prevention, and treatment. Its Annual Meeting (The Liver Meeting®) is the world’s largest and most influential academic event in hepatology, bringing together thousands of researchers, clinicians, and pharmaceutical experts from around the world each year to showcase the latest basic research, clinical trials, and therapeutic advances in viral hepatitis, metabolic dysfunction-associated steatotic liver disease (NAFLD/NASH), HCC, alcoholic liver disease, and other areas. With rigorous scientific standards and cutting-edge academic content, AASLD leads the direction of global hepatology development and serves as a core platform for the launches and academic exchanges of innovative therapies.
Dr. Gongxin He, Founder of CureGene, Invited to Deliver an On-Site Speech
About CureGene
Founded in 2018 and headquartered in China, CureGene is a clinical-stage biotech company advancing novel therapies for global unmet medical needs. Leveraging proprietary technology platforms, the company has built a diversified pipeline of first-in-class candidates with full global intellectual property rights. Current focus areas include cardio-cerebrovascular disorders, antiviral therapies, and metabolic dysregulation. Its interdisciplinary team integrates world-class scientists and industry veterans from leading multinational pharmaceutical companies, driving rapid translation from discovery, clinical development and commercialization. All pipeline assets are strategically positioned to address multibillion-dollar therapeutic markets, with lead programs demonstrating potential for best-in-class efficacy across preclinical and clinical studies.
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