Tocagen to Present Preclinical Data on Anti-PD-L1 Product Candidate Toca 521 at the 2018 Annual Meeting of The American Society of Gene & Cell Therapy (ASGCT)

SAN DIEGO, May 14, 2018 /PRNewswire/ -- Tocagen Inc. (Nasdaq: TOCA), a clinical-stage, cancer-selective gene therapy company, today announced preclinical data on Toca 521, a retroviral replicating vector (RRV) expressing a single-chain variable fragment targeting PD-L1, will be presented at the 2018 Annual Meeting of The American Society of Gene & Cell Therapy (ASGCT), held May 16-19 in Chicago.

In a preclinical study, Toca 521 reversed PD-1/PD-L1 mediated immune suppression, resulting in robust, durable and highly selective anti-tumor activity that was superior to systemically administered anti-PD-1 or anti-PD-L1 monoclonal antibodies. Tocagen expects to advance Toca 521 into investigational new drug application (IND) enabling studies this year.

In addition, previously disclosed clinical data and new preclinical results from an ovarian cancer model will be presented.

Summaries are provided below for new data sets, for which full posters will be placed on Tocagen's website following the presentation.

Presentation Type: Poster (Abstract: 111)
Title: PD-L1 Checkpoint Blockade Using a Single-Chain Variable Fragment Targeting PD-L1 Delivered by Retroviral Replicating Vector Enhances Anti-Tumor Effect in Cancer Models 
Presenter: Amy Lin, Ph.D., associate director of experimental virology at Tocagen
Date and Time: Wednesday, May 16, 5:30 p.m. CT
Summary:

• A RRV expressing a single-chain variable fragment targeting PD-L1, called Toca 521, was developed using Tocagen's proprietary cancer-selective gene therapy platform technology.
• Preclinical results demonstrated Toca 521 reversed PD-1/PD-L1 mediated immune suppression in a human in vitro cell culture system, and conferred robust, durable and highly selective anti-tumor activity compared to systemically administered anti-PD-1 or anti-PD-L1 monoclonal antibodies.
• These results indicate further development of Toca 521 is warranted to investigate the potential for improved safety and efficacy profiles compared to systemic monoclonal antibodies against the same checkpoint target. Toca 521 could also be useful in combination with other agents, including immuno-oncology therapies.  

Presentation Type: Oral presentation (Abstract: 344)
Title: Treatment of Recurrent HGG Patients with the Retroviral Replicating Vector Toca 511 and Toca FC Resulted in Durable Responses and Survival Lasting 3 Years or Longer: Immune Mechanisms and Molecular Analyses of Tumors 
Presenter: Douglas Jolly, Ph.D., executive vice president of research and pharmaceutical development at Tocagen
Date and Time: Thursday, May 17, 9:20-9:40 a.m. CT

Presentation Type: Poster (Abstract: 428)
Title: Toca 511-Mediated Prodrug Activator Gene Therapy: A Promising Therapeutic Strategy for Ovarian Cancer 
Presenter: Sara Collins, Ph.D., assistant scientist in the department of cell biology at the University of Miami Miller School of Medicine. These studies were performed in the laboratory of Noriyuki Kasahara, M.D., Ph.D., professor of cell biology and pathology at the University of Miami.
Date and Time: Thursday, May 17, 5:15 p.m. CT
Summary:

• Preclinical studies evaluating Toca 511 and 5-FC in a mouse model of ovarian cancer were conducted.
• Increased survival and reduced tumor burden was observed in mice with pre-existing tumors receiving Toca 511 followed by 5-FC, as compared to untreated controls.

About Toca 511 & Toca FC

Tocagen's lead product candidate is a two-part cancer-selective immunotherapy comprised of an investigational biologic, Toca 511 and an investigational small molecule, Toca FC. Toca 511 (vocimagene amiretrorepvec) 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, extended-release formulation of the 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 in the tumor microenvironment resulting in anti-cancer immune activation and subsequent tumor killing.

About Tocagen Inc.

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's lead investigational product candidate, Toca 511 & Toca FC, is under evaluation in a pivotal Phase 3 trial for recurrent high grade glioma (HGG), a disease with significant unmet medical need. The U.S. Food and Drug Administration (FDA) has granted Toca 511 & Toca FC Breakthrough Therapy Designation for the treatment of recurrent HGG and the European Medicines Agency (EMA) has granted Toca 511 PRIME (PRIority MEdicines) designation for the treatment of glioma. 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, expectations regarding the timing and success of our clinical trials and planned clinical trials, activities related to development of our current and future product candidates in additional indications and our plan to update our regulatory plans. 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.

Media Contact:

Monica May
Canale Communications
(619) 849-5383
monica@canalecomm.com  

Investor Contact:

Elizabeth Broder
Endurance Advisors
(646) 206-1246
ebroder@enduranceadvisors.com

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SOURCE Tocagen Inc.