Advances in the Clinical Development of Oncolytic Viruses

Introduction

Oncolytic viruses (OVs) represent a promising class of immunotherapeutic agents against tumors, capable of selectively infecting and killing cancer cells without damaging normal cells. The concept of using viruses to treat cancer dates back to 1891, with recent advancements leading to the development of third-generation OVs.

Clinical Trials and Findings

As of October 1, 2021, 408 clinical trials involving 31 OV products have been conducted, with phase I and phase II studies accounting for approximately 80% of all studies. OVs such as H101, T-VEC, G47Δ, OH2, T3011, and Pelareorep have demonstrated significant anti-tumor effects across various cancers, with only mild adverse events reported.

Mechanisms of Action

OVs employ multiple mechanisms to combat tumors, including specific replication in tumor cells, induction of chemokines to stimulate local and systemic antitumor immune responses, destruction of the tumor vascular system, and genetic modifications to enhance anti-tumor effects.

Challenges and Future Directions

Despite their potential, most OVs are still in the early stages of development, facing challenges such as improving targeting efficiency, selecting appropriate vector cells, overcoming antibody neutralization, and ensuring viral diffusion within tumors. Additionally, the impact of antiviral drugs on OV efficacy and the environmental safety of OV treatments are areas of concern.

Conclusion

OVs exhibit precise oncolysis and favorable safety profiles, offering a promising avenue for cancer treatment. However, further research is needed to optimize their effectiveness, safety, and administration methods, paving the way for personalized and precise immunotherapy in the future.