Viventia Presents Validating Evidence for Highly Differentiated De-immunized Payload for Oncology at 13th Empowered Antibodies Conference

- Viventia's Protein Toxin DeBouganin Shows Advantages in Uniform Killing of Diverse Cancer Cell Lines, Avoidance of Multi-Drug Resistance Affecting Small Molecule Toxins, and Efficacy against Cancer Stem Cells -

- Lead Program Based on deBouganin Platform Expected to Commence Second Clinical Trial in the First Quarter 2016 -

WINNIPEG, Manitoba, June 17, 2015 (GLOBE NEWSWIRE) -- Viventia Bio Inc., a late clinical-stage company advancing a broad pipeline of novel anti-cancer agents, today announced comprehensive data supporting advancement of the Company's systemic anti-cancer fusion constructs at the 13th Empowered Antibodies Congress, currently taking place in Barcelona, Spain, June 17-18, 2015. In an oral presentation, titled "Development of a protein toxin payload for systemic targeted therapy," Dr. Jeannick Cizeau, Director of Research at Viventia, is reporting today that the Company's lead de-immunized protein toxin, termed deBouganin, demonstrated potent and efficient killing of tumor cell lines from breast, lung, and gastric cancers, and showed activity against relatively quiescent cancer stem cells (CSCs) in preclinical testing. DeBouganin was able to successfully avoid multi-drug resistance (MDR) mechanisms that plague small molecule payloads. Additionally, in an earlier first-in-man study, Viventia confirmed the payload had been successfully de-immunized. Based on these collective findings, the Company expects to commence further clinical testing of its lead deBouganin Targeted Protein Therapeutic (TPT), designated VB6-901, in 1Q 2016.

Dr. Cizeau commented, "DeBouganin, Viventia's de-immunized version of the plant toxin Bouganin, offers compelling advantages compared to first-generation antibody-drug conjugate therapies that utilize small molecule payloads. As a ribosome inactivating protein, deBouganin has a cell cycle-independent mechanism of action, blocking cancer cell protein synthesis and killing diverse cancer cell types, including more slowly replicating CSCs, which are otherwise difficult to target. Further, the protein is not subject to the same efflux pumps responsible for small molecule drug resistance."

Dr. Cizeau added, "We are very pleased to be able to present comprehensive results validating the distinct advantages of our cytotoxic payload, and we look forward to continuing clinical trials next year."

Overview of deBouganin Results

  • deBouganin is modified through the elimination of T cell epitopes in order to reduce or prevent activation of an immune response. In preclinical studies, potency of deBouganin has been found to be similar to the original plant toxin. Immunogenicity profiling correlated with previous experience in patients and was comparable to a number of systemic agents (e.g., Herceptin® (trastuzumab)).
  • A conjugate of Herceptin and deBouganin showed equivalent potency or in some cases significantly greater potency against Her2+ cancer cell lines when compared to KADCYLA® (ado-trastuzumab emtansine), also referred to as T-DM1.
  • Free deBouganin demonstrated superior cancer cell line targeting, a key measure of potential safety, compared to T-DM1.
  • An earlier version of VB6-901 was tested against cancer cell lines with MDR and was found to be able to overcome resistance, versus comparators (doxorubicin, taxol).
  • In a Phase 1 human safety study, this earlier version of VB6-901 demonstrated no antibody responses against deBouganin in the majority of patients after eight weeks.
  • Both the Herceptin-deBouganin conjugate and a diabody- deBouganin conjugate demonstrated enhanced activity against CSCs versus T-DM1.

"Viventia has established compelling and extensive peer-reviewed validation for its lead TPT programs, and we are proud of the platform validation being presented at this week's meeting," stated Stephen Hurly, Viventia's Chief Executive Officer. "Bringing together the power of navigating antibodies with the cell-killing power of cytotoxic payloads holds great promise to improve areas of unmet medical needs. Our recently presented data, we believe, further evidence the strong potential of deBouganin in this area."

About Viventia Bio

Viventia Bio is a late clinical-stage company advancing a broad pipeline of novel anti-cancer agents based on the Company's Targeted Protein Therapeutics (TPTs) platform. TPTs are fully biologic fusion constructs containing antibody fragments, a proprietary linker, and protein toxin payloads. The Company believes its platform offers significant advantages in treating cancer versus earlier technologies, including superior tumor targeting and better cancer cell-killing properties thru the utilization of protein payloads versus small molecules, as well as enhanced linker stability and more efficient manufacturing.

Viventia's lead clinical candidates, Vicinium™ and Proxinium™, are anticipated to progress in Phase 3 testing in 2015 for locoregional treatment of patients with non-muscle invasive bladder cancer (NMIBC) and squamous cell carcinoma of the head & neck (SCCHN), respectively. Earlier-stage programs are focused on de-immunized, systemic candidates, including VB6-901, indicated for solid tumors and expected to continue clinical trials in the first quarter of next year, as well as additional preclinical candidates targeting solid tumors. Viventia was founded by life sciences entrepreneur and philanthropist Leslie L. Dan.

CONTACT: Justin Jackson, Burns McClellan on behalf of Viventia Bio 212-213-0006, ext.327 jjackson@burnsmc.comSource:Viventia Bio Inc.