Breakthrough in photoactivatable nanomedicine for the treatment of AMD

Key Takeaways

  • Researchers have developed a new treatment for wet AMD that is given intravenously rather than requiring eye injections.
  • The new treatment demonstrated excellent therapeutic efficacy in mice without any noticeable systemic or ocular side effects.

The development of abnormal, leaky blood vessels is a hallmark of wet age-related macular degeneration (AMD). Injections into the eye of antibodies against vascular endothelial growth factor (VEGF), which inhibit blood vessel formation, are the current first-line treatment for wet AMD. However, this invasive procedure is uncomfortable for patients and carries the risk of serious ocular complications. Therefore, there is an urgent need for novel formulations that enable the delivery of anti-angiogenic (inhibits blood vessel formation) agents into the eye without an eye injection, such as intravenous injection.

Additionally, anti-angiogenic agents have limited efficacy in regressing existing growth of abnormal new blood vessels. Photodynamic therapy (PDT) offers a clinical solution by utilizing non-toxic photosensitizers activated by specific wavelengths of light to generate reactive oxygen species (ROS), a type of unstable molecule that contains oxygen and that easily reacts with other molecules in a cell. ROS can damage and obliterate the new abnormal vessels. PDT is widely used for the treatment of polypoidal choroidal vasculopathy, a common subtype of wet AMD in Asia. Therefore, combining anti-angiogenesis therapy with PDT may offer a more effective approach to treating wet AMD, thus helping slow down the progression of the disease and improve the vision outcome for patients.

Researchers at LKS Faculty of Medicine of the University of Hong Kong (HKUMed), and collaborators from the Zhongshan Ophthalmic Centre of Sun Yat-sen University, Guangzhou developed a new light-activatable prodrug nanomedicine. Through the intravenous injection of the nanomedicine and application of light irradiation to diseased eyes, anti-angiogenic and photodynamic combination therapy can be activated, offering a minimally invasive alternative for the treatment of AMD and other ocular disorders characterized by abnormal blood vessel growth. The combination therapy demonstrated excellent therapeutic efficacy in mice without any noticeable systemic or ocular side effects. In addition, the formulation uses FDA-approved therapeutic agents and excipients, making it promising for future clinical translation. The research has been published in Advanced Science and a Patent Cooperation Treaty application was filed based on the research.

This work was supported by the National Natural Science Foundation of China Excellent Young Scientists Fund and the National Natural Science Foundation of China.

Source: The University of Hong Kong, ScienceDaily, December 5, 2023; see source article