The SITC poster titled, "Immunomodulation in peripheral blood and tumor following Toca 511 & Toca FC treatment in patients with solid tumors," was a summary of the results in the Toca 6 Phase 1b, single arm study of Toca 511 and Toca FC in advanced non-CNS solid tumors. The objectives of the study were to assess changes in immune activity of peripheral blood mononuclear cells (PBMCs) relative to baseline following treatment and to evaluate immune cell modulation in the tumor microenvironment from tumor biopsies taken at baseline compared to biopsies collected following treatment.
The Toca 6 Phase 1b, single arm study of Toca 511 and Toca FC in advanced non-CNS solid tumors demonstrated vector deposition, immune activity, a potential signal of clinical activity and a favorable safety profile.
Treatment was generally well tolerated, with predominantly Grade 1 and 2 treatment-related gastrointestinal adverse events. Most patients enrolled (81%) had metastatic colorectal cancer; the median lines of prior chemotherapies was four (1, 12).
Clinical activity was supported by observations of partial response and stable disease. The median overall survival was 9.6 months (95% CI 6.3, 16.4) in this heavily pre-treated population.
Toca 511 and Toca FC was associated with a T-cell mediated immune response in peripheral blood and metastatic tumor in some patients, consistent with the mechanism of action observed in preclinical models.
Peripheral blood T-cells shift from naïve to effector phenotypes indicating that T-cells are encountering their target antigens, potentially including proteins released by tumor cell killing.
Expansion of CD4+ memory T-cells after treatment is consistent with engagement of the adaptive immune system.
Increased post-treatment quantities of B-cells further suggests immune activation during the course of Toca 511 and Toca FC therapy.
Toca 511 and Toca FC led to a decrease of CD11b+ myeloid cells in five of six patients with evaluable colorectal metastasis. This immune fluorescence analysis suggests a decrease in the immunosuppressive myeloid cells, as seen in preclinical models, and potentially makes the tumor and the tumor microenvironment more conducive to immunologic modulation.
"Data from our poster at SITC are encouraging and support the planned exploration of our Toca regimen in non-muscle invasive bladder cancer," said Marty Duvall, chief executive officer of Tocagen. "In addition, we look forward to presenting Toca 5 analyses at the upcoming SNO conference Toca 5 analyses including subgroups and molecular data in addition to details of the planned NRG Oncology trial in patients with newly diagnosed glioblastoma."
Details of the SNO presentations are as follows. Copies of the presentations will be available on Tocagen's website following the presentations.
Presentation Type: Plenary Presentation (Abstract: LTBK-08) Title: Toca 511 & Toca FC Versus Standard of Care in Patients With Recurrent High Grade Glioma Presenter: Timothy Cloughesy, M.D., director of the University of California, Los Angeles, Neuro-Oncology Program Date and Time: Friday, Nov. 22, 11:50 a.m. - 12:00 p.m. MST
Presentation Type: Poster Presentation (Abstract: RBTT-11) Title: NRG Oncology NRG-BN006: A phase II/III randomized, open-label study of Toca 511 and Toca FC with standard of care compared to standard of care in patients with newly diagnosed glioblastoma Presenter: Manmeet Ahluwalia, M.D., head of operations, Burkhardt Brain Tumor and Neuro-Oncology Center, Cleveland Clinic. Date and Time: Saturday, Nov. 23, 5:00 p.m. - 7:00 p.m. MST
About Toca 511 & Toca FC Tocagen's lead product candidate is a two-part cancer-selective immunotherapy comprising an investigational biologic, Toca 511 (vocimagene amiretrorepvec), and an investigational small molecule, Toca FC (flucytosine, extended-release). Toca 511 is a retroviral replicating vector (RRV) that selectively infects cancer cells and delivers a gene for the enzyme, cytosine deaminase (CD). Through this targeted delivery, infected cancer cells carry the CD gene and produce CD. Toca FC is an orally administered prodrug, 5-fluorocytosine (5-FC), which is converted into an anti-cancer drug, 5-fluorouracil (5-FU), when it encounters CD. 5-FU kills cancer cells and immune-suppressive myeloid cells resulting in anti-cancer immune activation and subsequent tumor killing.
About Tocagen Tocagen is a clinical-stage, cancer-selective gene therapy company developing first-in-class, broadly applicable product candidates designed to activate a patient's immune system against their own cancer. Tocagen plans to evaluate its lead investigational product candidate, Toca 511 & Toca FC, in a Phase 2/3 trial for patients newly diagnosed with glioblastoma, sponsored by the NCI and conducted by NRG Oncology, and a Phase 1 trial in patients with non-muscle invasive bladder cancer. Tocagen is advancing preclinical programs from its versatile gene therapy platform that represents a new approach in cancer immunotherapy. For more information about Tocagen, visit www.tocagen.com.
Forward-Looking Statements Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding our business plans and objectives, including plans related to development of our product candidates. Risks that contribute to the uncertain nature of the forward-looking statements include: our ability to execute on our strategy; and risks related to clinical development. These and other risks and uncertainties are described more fully under the caption "Risk Factors" and elsewhere in Tocagen's filings and reports with the United States Securities and Exchange Commission. All forward-looking statements contained in this press release speak only as of the date on which they were made. Tocagen undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.