The Company has developed novel retroviral non-replicating vectors (RNVs) designed to activate the immune system selectively against the tumor. Our lead product, “Toca Gamma” is under preclinical development and we plan to start clinical trials as soon as possible.
Toca Gamma is designed to act in the local cancer environment to create anticancer specific immune responses. In contrast, systemically administered immunotherapeutics in development by others activate the immune system more generally and are therefore less likely to achieve anticancer specificity. Toca Gamma is designed to leverage the immune system to clear locally injected cancerous tumors as well as to create an “arsenal” of targeted immune cells to kill more distant metastatic cancer cells. The targeted immune cells are anticipated to act as “guided missiles” to specifically seek and destroy the metastatic cancer cells not injected.
Using an earlier version of this approach, Tocagen scientists have previously demonstrated anticancer activity and prolonged survival in humans with stage 4 metastatic melanoma. An immunotherapeutic vector built by Viagene Inc. (a gene therapy company co-founded previously by certain members of the Tocagen management team) previously reported, as shown below, durable responses in several patients as well as a significant survival advantage in a higher dose (six courses) group compared to a lower dose (single course) group in a small human trial in patients with stage 4 melanoma.
Tocagen believes that a non-replicating vector delivering gamma interferon should activate the immune system selectively against the cancer.
Brain Cancer (High Grade Glioma)