Inovio Biomedical Corporation (NYSE Amex: INO), a leader in DNA vaccine design, development and delivery, announced today interim safety and immunogenicity data from its therapeutic cervical cancer vaccine (VGX-3100) trial. VGX-3100 is a DNA vaccine targeting the E6 and E7 proteins of human papillomavirus (HPV) types 16 and 18 and is delivered via in vivo electroporation. The vaccine was found to be generally safe and well tolerated, and achieved significant cellular and humoral immune responses at the lowest dose administered. Dr. David B. Weiner, Professor, University of Pennsylvania and Chairman of Inovio’s Scientific Advisory Board, presented the data at the Vaccine 3rd Global Congress in Singapore in a presentation entitled, “Delivering on the Promise of DNA Vaccines for HIV and Cancer: From Bench to Clinical Data.”
This phase I clinical trial was designed to test the safety and immunogenicity of VGX-3100 in women with a previous history of cervical intraepithelial neoplasia (CIN) 2/3, a precursor lesion prior to the development of cancer. This dose escalation study is enrolling patients in three cohorts of six subjects each with DNA vaccine doses at 0.6 mg (0.3 mg each of two DNA plasmids), 2.0 mg, and 6.0 mg. The immunization regimen consists of each subject receiving three immunizations at the indicated dose. The vaccine is delivered using Inovio’s proprietary CELLECTRA® intramuscular electroporation delivery device.
Inovio has completed immunizations of the lowest dose cohort. The interim safety analysis indicated that all six subjects tolerated the vaccine administration and electroporation procedure well over each of the three vaccinations. In general, reported adverse events and injection site reactions were mild to moderate and required no treatment.
The preliminary immunological analysis of blood samples collected before and after vaccine administration indicated the induction of vaccine-specific immune responses against the target antigens produced by the vaccine. Antigen-specific cytotoxic T-lymphocyte (CTL) responses were observed against all four antigens, i.e. E6 and E7 proteins for HPV types 16 and 18. The subjects were considered as responders if antigen-specific CTL responses greater than 50 spot forming units (SFU) per million white blood cells were observed (50 being a benchmark significantly beyond the normally existing background presence of CTL). By this measure, 3 of 6 vaccinated subjects (50%) were deemed to be responders and yielded CTL responses ranging from 250 – 450 SFU per million cells after three immunizations. Inovio’s scientists also tested the samples for antibody responses against the target antigens and observed strong antibody responses in 5 of 6 subjects (83%). Antibodies were generated to all three antigen components tested. Specific antibody responses to tumor antigens can function as an important surrogate potency marker for determining the immunogenicity of a vaccine. Furthermore, Inovio believes they generally underscore the potential usefulness of the Inovio DNA vaccine platform in the vaccine arena.