Oncolytic VSV Primes Differential Responses to Immuno-oncology Therapy

Area of Science:

• Oncolytic virotherapy
• Immunotherapy
• Cancer treatment

Background:

• Vesicular stomatitis virus encoding the IFNβ transgene (VSV-IFNβ) demonstrates potent oncolytic activity against solid tumors.
• Oncolytic viruses may enhance anti-tumor immune responses and sensitize tumors to checkpoint inhibitors.
• Novel immuno-oncology agents, such as T cell agonists, are being developed to augment oncolytic virus efficacy.

Purpose of the Study:

• To investigate the mechanisms of action of VSV-IFNβ.
• To evaluate the combination therapy of VSV-IFNβ with checkpoint inhibitors and OX40 agonists.
• To understand how these combinations impact anti-tumor immunity.

Main Methods:

• Characterization of VSV-IFNβ's mechanisms, including direct cell killing and immune stimulation.
• Assessment of VSV-IFNβ in combination with checkpoint inhibitors and OX40 agonists in preclinical models.
• Analysis of viral replication, transgene expression, and immunophenotypic changes.

Main Results:

• VSV-IFNβ exhibits direct cell killing, innate immune stimulation, CD8 T cell recruitment, and regulatory T cell depletion.
• VSV-IFNβ promotes CD8 T cell responses against endogenous tumor antigens.
• Combination of VSV-IFNβ with checkpoint inhibitors significantly enhanced anti-tumor function and tumor growth inhibition without increasing viral activity.
• No enhancement was observed when combining VSV-IFNβ with OX40 agonists.

Conclusions:

• VSV-IFNβ has multifaceted anti-tumor mechanisms.
• Checkpoint inhibitors synergize with VSV-IFNβ to improve anti-tumor efficacy, likely by preventing T cell exhaustion.
• VSV-IFNβ combined with checkpoint inhibitors represents a promising strategy for solid tumor treatment.