Data Examines Induction of Systemic Immune Response in Multiple Tumor Types

The poster entitled, "Intralesional Injection with PV-10 Induces a Systemic Anti-tumor Immune Response in Murine Models of Breast Cancer and Melanoma," was presented by Shari Pilon-Thomas, Ph.D., Immunology Program, Moffitt Cancer Center.

Provectus’s PV-10, a 10% solution of Rose Bengal, is currently being examined as a novel cancer therapeutic. It is designed to selectively target and destroy cancer cells without harming surrounding healthy tissue, significantly reducing potential for systemic side effects. In melanoma patients, intralesional (IL) injection of PV-10 has led to regression of injected lesions as well as distant metastases (i.e., bystander lesions).

The Moffitt study examined the immunologic mechanism of PV-10 treatment in murine models of breast cancer and melanoma to determine how IL PV-10 therapy induces the systemic anti-tumor immune response apparent in bystander responses in clinical trial participants. In the current work, IL injection of PV-10 led to regression of injected and untreated contralateral subcutaneous lesions in the MT-901 breast cancer model, with a significant increase in survival in mice treated with IL PV-10 versus those treated with IL saline. In a synchronous flank tumor/lung metastasis model, there was a significant reduction in lung metastases and subcutaneous tumor size in mice treated with IL PV-10 versus those treated with IL saline. Injection of PV-10 into the opposite, non-tumor bearing flank, did not affect the size of subcutaneous lesions nor the number of lung metastases. Splenocytes harvested from PV-10-treated mice exhibited tumor-specific enhancement of interferon-gamma production and cytotoxicity against the treated cell line, along with adoptive transfer of immunity upon implantation in naïve mice. A copy of the poster is available at the following link:

http://www.pvct.com/publications/SPTAACR2013-Final.pdf

Dr. Pilon-Thomas commented, “The findings of this study confirmed not only that PV-10 induces tumor-specific immunity after a single treatment with IL-PV-10 in multiple tumor types, but that the ablative process is critical for this in situ stimulation of the immune system. The data also show that T cells play a critical role in this response. We feel this is a promising direction for additional translational research that will further define the processes that occur systemically following PV-10 treatment.”