Remodeling the Tumor Microenvironment for CAR-T Efficacy

The therapeutic rationale for combining oncolytic viruses with CAR-T cells is based on a sequential, two-step attack. Solid tumors have developed robust mechanisms to exclude effector T-cells. OVs can dismantle these defenses.

Through direct oncolysis and the release of tumor-associated antigens, OVs can initiate a potent local inflammatory response. This process achieves several objectives:

• Increases chemokine expression to attract T-cells to the tumor site.

• Downregulates immunosuppressive cell populations within the TME.

• Enhances antigen presentation, making tumor cells more visible to the immune system.

This conditioning of the tumor bed creates a permissive environment for CAR-T cells to function effectively upon arrival. Our study designs focus on optimizing the dosing and timing of each agent to maximize this synergistic effect.

Multi-Modal Endpoints for Quantifying Synergy

A singular reliance on caliper measurements of tumor volume is insufficient for evaluating these complex immunotherapies. A deeper understanding of the biological activity is necessary to build a compelling IND package. This approach provides high-resolution pharmacology data to validate complex biologicals.

We integrate several analytical methods to build a complete efficacy profile:

• Immune Cell Infiltration: Flow cytometry and histology are used to quantify the density and phenotype of CAR-T cells and other immune subsets within the tumor.

• Spatial Relationships: Multiplex immunofluorescence allows for the visualization of CAR-T cells in proximity to tumor cells and other key structures within the TME.

• Systemic Response: Cytokine and chemokine profiling of peripheral blood provides a longitudinal view of the systemic immune activation and potential safety liabilities.

• Safety & Biodistribution: We conduct comprehensive non-target tissue biodistribution and toxicology assessments to ensure the combination is well-tolerated.

Watch the full-length video ‘DIVERSIFYING THE VALUE CHAIN’

Translational Insights from Advanced Vector Programs

The principles for de-risking complex biologicals are consistent across modalities. For example, insights from gene therapy development highlight the value of using multiple, cross-species models to build a robust safety and efficacy profile, a strategy directly applicable to predicting the human response to novel OV/CAR-T combinations (PMID: 35333110).

Similarly, the use of humanized models to confirm therapeutic engagement with a human-specific target has proven effective in validating vector-based therapies (PMID: 22985273). This same approach can be leveraged to verify a human CAR construct’s activity against its intended tumor antigen in an in vivo system. Our >100,000 sq ft GxP-compliant facility supports these complex studies, contributing to a typical 18-24 month IND timeline. This rigorous, translational approach has supported our partners in achieving a 100% IND success rate since 2019, with the Franklin Biolabs brand itself launching in 2024.