PD-1-Enhanced HIV Therapeutic Vaccine ICVAX® Completes Phase I Clinical Trial, Moving Closer to Real-World Application
Updated: Aug 12
In a major translational achievement for Hong Kong’s biomedical innovation sector, the Centre for Virology, Vaccinology and Therapeutics (CVVT) is pleased to highlight significant progress in the development of ICVAX®, a novel therapeutic DNA vaccine aiming to achieve a functional cure for HIV.
Led by Prof. Zhiwei Chen, Deputy Director of CVVT, Director of the AIDS Institute at the LKS Faculty of Medicine, The University of Hong Kong (HKUMed), and Chair Professor of Immunology and Immunotherapy, the project represents over 13 years of rigorous research and translational work in collaboration with a commercial biotechnology partner, Yicura 醫克生物 (formerly Immuno Cure BioTech).
The breakthrough was recently featured in an exclusive report by TVB News, showcasing Hong Kong’s growing ecosystem in driving world-class translational medicine from university laboratories to clinical implementation.
The Challenge: Beyond Lifelong Antiretroviral Therapy
Current management for people living with HIV (PLWH) relies heavily on combination antiretroviral therapy (cART). While cART successfully suppresses viral replication to undetectable levels, it cannot eradicate dormant viral reservoirs hidden within infected host cells. Consequently, patients require lifelong daily medication; stopping therapy leads to rapid viral rebound.
ICVAX® was developed to address this clinical challenge by targeting a "functional cure" - a state where the patient’s own immune system maintains long-term viral suppression below detectable limits without requiring continuous cART medication.
Innovation Driven by 13 Years of Research
ICVAX® utilises a patented platform technology that encodes a soluble PD-1 domain fused to a bivalent chimeric HIV antigen.
Mechanism of Action: The protein mechanism first selectively targets and activates dendritic cells via PD-1 engagement, subsequently inducing potent and long-lasting CD8+ protective T-cell immune responses.
Eliminating Viral Reservoirs: These broad-spectrum T cells are capable of targeting and destroying viral reservoirs, mimicking the protective functional immune signatures found in rare individuals who suppress HIV naturally without drugs.
Phase I Clinical Trial Results
In collaboration with the CUHK Phase 1 Clinical Trial Centre and Shenzhen Third People's Hospital, a Phase I clinical trial evaluating ICVAX® was successfully completed with promising results:
Safety Endpoints Met: The vaccine demonstrated an outstanding safety profile across all trial cohorts, with no treatment-related severe adverse events recorded.
Robust Immunogenicity: Participants receiving the optimal dosage exhibited more than a 2-fold increase in functional, HIV-specific T-cell responses.
Paving the Way for Phase II: Armed with successful safety and immunogenicity profiles, CVVT, HKUMed, and Yicura are actively preparing for multi-centre Phase II clinical trials to evaluate real-world efficacy during analytical treatment interruptions (ATI).
Strong Government Support via RGC Theme-based Research Scheme
Translational milestones of this magnitude require sustained financial and institutional backing. Supported by the Hong Kong SAR Government's ongoing commitment to strengthening local innovation and technology, the Research Grants Council (RGC) has allocated substantial funding through its competitive Theme-based Research Scheme (TRS).
The overarching project, titled "Sustained cART-free HIV-1 Control by Immunotherapeutic Interventions," was recently awarded HK$66.7 million for a second five-year term (2026–2031). This brings the cumulative RGC TRS grant support for Prof. Chen’s HIV vaccine translational pipeline to HK$113.8 million.
Commitment to Global Health Impact
As an InnoHK research centre, CVVT remains dedicated to bridging the gap between fundamental laboratory discoveries and clinical deployment. The successful Phase I trial of ICVAX® serves as a powerful testament to the synergy between academic expertise at HKUMed, industrial execution by Yicura, and dedicated public research funding in Hong Kong.
CVVT will continue to work closely with its academic, clinical, and industrial partners to advance ICVAX® through subsequent trial phases, striving to bring a home-grown functional cure for HIV to patients worldwide.
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