Toca 5 Phase 3 Trial Results Presented at the Society for Neuro-Oncology Annual Meeting

SAN DIEGO, Nov. 22, 2019 /PRNewswire/ -- Tocagen Inc. (Nasdaq: TOCA), a clinical-stage, cancer-selective gene therapy company, today announced presentation of the full results from the Toca 5 Phase 3 trial evaluating Toca 511 & Toca FC in patients with recurrent high grade glioma (HGG) at the Society for Neuro-Oncology (SNO) Annual Meeting. The data were presented on behalf of the Toca 5 clinical investigators by Timothy Cloughesy, M.D., professor of neurology and director of the neuro-oncology program at the University of California, Los Angeles and principal investigator for the Toca 5 trial.

Trial design and demographics
Toca 5 was a Phase 3 randomized trial of Toca 511 & Toca FC in patients with recurrent HGG, undergoing resection. The trial involved 67 sites globally and enrolled 403 patients. Patients were randomized 1:1 prior to surgical resection to receive either the Toca 511 & Toca FC regimen or standard of care (SOC) treatment (lomustine, temozolomide or bevacizumab). The primary endpoint of the trial was overall survival (OS) and secondary endpoints included durable response rate, durable clinical benefit rate, duration of durable response and overall survival at 12 months. Patients were stratified based on IDH1 mutation status, KPS and geographic region. The baseline demographics and disease characteristics of the study were well balanced in the intent to treat populations and the 26 pre-specified subgroups.

Results
As previously announced, the trial did not meet the primary or secondary endpoints. The safety, tolerability and adverse event profile of Toca 511 & Toca FC was as expected for this patient population. In the ITT population, the median number of cycles of Toca FC was two and the median number of cycles across the SOC options ranged from two to four.

In a pre-planned subgroup analysis, subjects with second recurrence (N=60) showed a 57% risk reduction for death when treated with Toca 511 and Toca FC (21.82 months median OS compared to 11.14 months, HR=0.43, p=0.0162) representing an approximate doubling of survival. Further analysis of the second recurrence subgroup showed that patients with IDH1 mutations and anaplastic astrocytoma (AA), had the greatest survival benefit (HR=0.102, p=0.009). Second recurrence patients with IDH1 mutations and AA received a median of six cycles of Toca FC compared to a median of three cycles across the SOC options.

"The positive outcome for patients at second recurrence in the Toca 5 trial are compelling, despite the disappointment of the overall trial results," said Dr. Cloughesy. "Combined with an acceptable safety profile, these data support a potential opportunity to address the high unmet needs of this well-defined patient population and should inform any future development of the Toca 511 & Toca FC regimen."

In addition, molecular data from the Toca 5 trial were presented by Michael A. Vogelbaum, M.D., Ph.D., program leader of neuro-oncology and chief of neurosurgery at the Moffitt Cancer Center, at the Society for Neuro-Oncology and Society for CNS Interstitial Delivery of Therapeutics' 3rd Joint Conference on Therapeutic Delivery to the CNS. Data indicated that the immunological profile at baseline was well balanced between the two arms of the trial. In addition, data showed that patients in the second recurrence, IDH1 mutations and AA subgroups had a more robust immune profile prior to treatment. These data suggest that patients within these subgroups may have been favorably predisposed to generate anti-tumor immune responses.

"We have conducted a thorough analysis of the Toca 5 data and a subgroup of patients appear to benefit from treatment with Toca 511 & Toca FC," said Marty Duvall, chief executive officer of Tocagen. "We have submitted the data to FDA and anticipate providing an update once we have more clarity on potential next steps for our recurrent brain cancer program."

Copies of Dr. Cloughesy's and Dr. Vogelbaum's presentations are available on Tocagen's website.

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 any potential future development of Toca 511 & Toca FC or our plans to provide additional clarity on our recurrent brain cancer program in the coming months. Risks that contribute to the uncertain nature of the forward-looking statements include: the success, cost and timing of our product candidate development activities and planned clinical trials; our ability to execute on our strategy; regulatory developments in the United States and foreign countries; and our estimates regarding expenses, future revenue and capital requirements. 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.

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SOURCE Tocagen Inc.