A Self-Assembling Vaccine, VTX-067, targeting E6/E7 proteins of Human Papilloma Virus Induces T Cell-Mediated Immune Responses and Inhibits HPV E6/E7 Expressing Tumor Growth in a C57/B6 Mouse Model.

---

Presentation Time: 02:15 PM - 03:30 PM
Poster Board Number: B222
Abstract ID: 6108

Presenting Author:
Yohannes Gemechu , Postdoc at Massachusetts Gen. Hosp., Harvard Med. Sch.

Abstract:

Background and Methods: Human papillomavirus (HPV) infection is associated with skin and mucosal papillomas or warts and cervical, anal, and head and neck cancer. To fill a significant unmet need to treat HPV induced cancers, we developed a novel, broadly immune activating, self-assembling vaccine (SAV) which consists of a Mycobacterium tuberculosis heat shock protein 70 (MtbHSP70)-avidin (MAV) as an adjuvant that spontaneously self-assembles with biotinylated immunogenic peptides targeting the E6 and E7 proteins of HPV (VTX-067). The anti-tumor benefit of our vaccine, VTX-067, was tested in a TC-1 cell line (20,000 cells/mouse) induced tumor-bearing C57BL/6J mouse model. Mice (group size = 12) were vaccinated intradermally with VTX-067 on days 3, 17, and 24 post-TC-1 inoculation.

Result: C57BL/6J mice vaccinated with VTX-067 generated statistically significant CD8⁺IFNg⁺ responses at doses 130, 215 and 350µg and CD4⁺IFNg⁺ T cell responses at vaccine doses 215 and 350µg compared to saline-treated groups. Mice vaccinated with VTX-067 at doses of 80, 130, and 215μg survived significantly longer (   p < 0.0001; log-rank followed by Mantel-Cox  ) with markedly slower tumor growth than mice in control groups.

 Conclusion: Our study demonstrated that VTX-067 is safe and well-tolerated in mice, and three dose levels of VTX-067 provided both statistically significant T cell-mediated viral antigen-specific responses and increases in overall survival and tumor volume reduction.