Tocagen Presents Updated Clinical and Preclinical Data at Scientific Meetings

SCOTTSDALE, Ariz. – Nov. 21, 2016 – Tocagen Inc., a clinical-stage, cancer-selective gene therapy company, today announced updated interim data from ongoing Phase 1 and preclinical studies of Toca 511 (vocimagene amiretrorepvec) in combination with Toca FC (extended-release 5-fluorocytosine) were presented at the 21st Annual Scientific Meeting and Education Day of the Society for Neuro-Oncology (SNO), the 2nd CNS Anticancer Drug Discovery and Development Conference and the Society for Immunotherapy of Cancer (SITC) 31st Annual Meeting.

“Given the high unmet need for patients with brain cancer, we are particularly encouraged that all patients with an objective response from our Phase 1 trial remain alive,” said Harry Gruber, M.D., president, research and development at Tocagen. “In addition, clinical and preclinical data presented at these three conferences further illustrates the breadth and depth of the Toca 511 & Toca FC program.”

Highlights of data from the podium and poster presentations are below. More information about the presentations can be found on Tocagen’s website. In the ongoing clinical studies, Toca 511 is administered first, followed by cycles of orally administered Toca FC. The ongoing Phase 2/3 trial, called Toca 5, is enrolling patients with recurrent glioblastoma or anaplastic astrocytoma.

Data presented at SNO:

Updated Survival, Safety Data for 126 Patients with Recurrent High-Grade Glioma Receiving Toca 511 & Toca FC

  • Pooled data from three open-label, Phase 1 ascending-dose studies of patients with high-grade glioma who received Toca 511 & Toca FC continued to show the treatment was well tolerated and survival was favorable compared to historical benchmarks.
  • In the subset of patients in the higher dose cohorts that mirror the patient population under evaluation in the ongoing Toca 5 trial,1 there was a clinical benefit rate of 41.7%, with 3 complete responses, 2 partial responses and 5 patients with stable disease (N=24). All patients with an objective response remain alive 24 to 43 months from study entry, and the median duration of response was 20.7 months.2

Immune System Activated Following Treatment with Toca 511 & Toca FC in Phase 1 Trial Evaluating Patients with High-Grade Glioma

  • Significant increases in proliferating peripheral blood T cells seen after treatment with Toca 511 & Toca FC, compared to patient baselines.
  • Significant changes in total and dividing CD3+, CD8+ and CD4+ peripheral blood T-cell populations were sustained in a complete response patient compared to non-responding patient.

Safety of Toca 511 Supported by Study of Potential Integration Sites and Mutation Profile

  • No evidence of clonal expansion or preferential insertion into cancer-linked genes seen following systematic profiling of Toca 511 using patients’ blood samples.
  • Data supports absence of pathogenicity associated with Toca 511, a replicating gammaretrovirus, and is consistent with observations from clinical safety profile.
  • No evidence of autoimmunity reported.

Data presented at the CNS Anticancer Drug Discovery and Development Conference:

Successful Cancer-Selective Gene Delivery Following Intravenous Toca 511 Delivery in Phase 1 Trial Evaluating Patients with Recurrent High Grade Glioma

  • Preliminary overall survival results in 17 patients showed a median overall survival of 13.6 months and survival probability at 12 months of 57.5%.
  • Following intravenous administration of Toca 511, viral DNA was detected in nearly 50% of the subsequently resected tumor samples, and the presence of viral genes increased in a dose-dependent manner with over 80% of patients having viral DNA at the highest dose.

Efficacy of Checkpoint Inhibitors Improved When Combined with Toca 511 and 5-Fluorocytosine in Mouse Model of Glioma

  • Tumor burden significantly reduced in mice implanted with glioma cells and treated with PD-1 and CTLA-4 antibodies in combination with Toca 511 and 5-fluorocytosine (5-FC), respectively.
  • Immunotherapeutic benefits of either therapy were not compromised by combining treatments.

Data presented at SITC:

Gene Transfer of Cytosine Deaminase with Toca 511 and Subsequent Treatment with 5-FC Induces Anti-Tumor Immunity

  • Toca 511 and 5-FC is highly effective at concentrating 5-FU at the site of the tumor and significantly reducing tumor burden in vivo in a syngeneic glioma model.
  • Toca 511 and 5-FC significantly depleted immunosupressive myeloid cells and increased tumor-associated immune infiltrates in the tumor microenvironment.
  • Toca 511 and 5-FC induced anti-tumor immunity is T-cell mediated.
  • Complements recent publication in Neuro-Oncology demonstrating the combination of Toca 511 and 5-FC with lomustine was well tolerated and generated a robust immunotherapeutic response in preclinical models of brain cancer.

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. The company is developing its lead investigational product candidate, Toca 511 (vocimagene amiretrorepvec) & Toca FC (extended-release 5-fluorocytosine), initially for the treatment of recurrent high grade glioma (HGG), a disease with significant unmet medical need. Tocagen has initiated the Phase 2 portion of a randomized, controlled Phase 2/3 clinical trial of Toca 511 & Toca FC in patients with recurrent HGG, which is designed to serve as a potential registrational trial. More information about the clinical trial can be found at www.tocagen.com/toca5.  Tocagen has initiated a clinical trial of Toca 511 & Toca FC in metastatic cancers, including colorectal, pancreatic, lung, breast, renal and melanoma. Tocagen obtained Fast Track designation from the U.S. Food and Drug Administration for Toca 511 & Toca FC as a treatment of recurrent HGG and Orphan drug designation for the treatment of glioblastoma multiforme (GBM), a subset of HGG. Tocagen has received grant support from leading brain cancer foundations, including Accelerate Brain Cancer Cure (ABC2), National Brain Tumor Society (NBTS), American Brain Tumor Association (ABTA), Musella Foundation and Voices Against Brain Cancer (VABC). For more information, visit www.tocagen.com or follow @Tocagen.

1First or second recurrence of recurrent glioblastoma or anaplastic astrocytoma; no prior bevacizumab for recurrence; recurrent tumor less than or equal to 5 centimeters.

2Data cutoff date was October 2016. Responses were assessed using Macdonald Criteria including MRI assessment by independent radiology review and clinical data.