Positive Clinical Trial Results for Immunovaccine?s DPX-0907 Published in Journal of Translational Medicine

Novel Cancer Immunotherapy Generates Polyfunctional T Cell Responses in Multiple Tumor Types; Triggers Increases in Antigen Targeted CD8+ T Cells

Halifax, Nova Scotia; August 6, 2012 – Immunovaccine Inc. (“Immunovaccine” or the “Company”) (TSX-V: IMV), a clinical stage vaccine company, today announced the publication of positive results from a Phase I clinical trial of the Company’s DPX-0907 cancer vaccine in the Journal of Translational Medicine. The published paper details new findings on specific polyfunctional T cell responses generated by DPX-0907, as well as previously announced positive safety and immune response findings from the study. The peer-reviewed paper, entitled “First-in-Man Application of a Novel Therapeutic Cancer Vaccine Formulation with the Capacity to Induce Multi-functional T cell Responses in Ovarian, Breast and Prostate Cancer Patients,” is now accessible in the online version of the Journal of Translational Medicine.
 

DPX-0907 is a unique multi-targeted therapeutic vaccine designed to train the immune system to recognize and attack cancer cells. The immunotherapy combines seven tumor associated antigens (TAAs) with Immunovaccine’s novel DepoVax™ adjuvanting delivery platform, allowing for the creation of a depot effect upon vaccination that presents the antigens and adjuvant to the immune system for a prolonged period of time. Treatment with DPX-0907 is designed to train the body’s T cells, sophisticated white blood cells that play a key role in fighting cancer, to recognize the antigens incorporated into the vaccine. In doing so, the T cells become programmed to specifically target and attack cancer cells, while leaving normal healthy cells unharmed. By incorporating multiple target antigens, DPX-0907 attempts to attack cancer cells through multiple avenues and potentially minimize the cancer cells’ demonstrated ability to edit and escape the impact of individual antigens.

As previously reported, study data showed that 61 percent (11/18) of the trial’s evaluable cancer patients, and more specifically 89 percent (8/9) of evaluable study patients with breast or ovarian cancer, experienced the desired targeted T cell responses against one or more of the seven key cancer-specific antigens contained in DPX-0907. In a majority of responding patients, the antigen-specific T cells triggered by DPX-0907 treatment secreted multiple type 1 cytokines, indicating the T cells possess the polyfunctional activity that has been increasingly associated with host protection in preclinical vaccine and tumor immunotherapy models. This finding suggests that DPX-0907 may be generating clinically-relevant immune responses and that the selected cancer-specific antigens have been combined with a suitably immunogenic delivery mechanism.

Newly disclosed data in the publication demonstrated that 82 percent (9/11) of the study’s responders experienced at least a two-fold increase in the frequency of antigen-specific, cytokine secreting CD8+ T cells compared to baseline. Eight of those patients showed antigen-specific CD8+ T cells that produced more than one cytokine simultaneously. Researchers arrived at this finding by specifically analyzing blood samples with a multi-parametric intracellular cytokine staining assay designed to monitor the activation of antigen-specific CD8+ T cells as a function of the number of activation markers, or cytokines, induced by the vaccine. These findings illustrate DPX-0907’s potential in generating a meaningful therapeutic response as CD8+ T cells are the cytotoxic T cells responsible for destroying tumor cells.

As previously announced, 73 percent of the study’s immune responders generated a response following the first vaccination suggesting favorable immune induction potential for DPX-0907 and 64 percent maintained a persistent response at one month following a third vaccination. When analyzing the results in breast and ovarian cancer specifically, 56 percent of these patients generated an immune response following the first vaccination, with the immunological response rate increasing to 89 percent after three vaccinations. This compares favorably with other clinical trials testing therapeutic vaccines in breast and/or ovarian patients with a similar disease profile. For example, studies of peptide-based antigens delivered in emulsion formulations have generally produced an immunological response rate of 50-to-60 percent after multiple immunizations.

Although the focus of this study was to evaluate antigen-specific CD8+ T cells, CD4 responses against a T helper peptide included in the vaccine were also detected. The CD4 responses correlated with antigen-specific CD8+ T cell responses in the same assay, supporting the hypothesis that the CD4 responses may have facilitated the generation of the specific CD8+ T cells observed. The CD4 or “helper” epitope, which was included in the vaccine to assist in the activation of CD8+ T cells, constitutes an important vaccine feature included in DPX-0907.

Additional new data in the publication demonstrated a key association between the achievement of immune responses during the study and the patients’ level of disease burden. A detailed analysis showed that the different study patient populations possessed key differences, namely that the breast and ovarian cancer patients had responded favorably to previous treatments (stable disease or complete response), whereas the majority of prostate cancer patients presented with late stage (Stage IV) disease and rising prostate specific antigen (PSA) levels even though they had all undergone at least three previous treatments. These dynamics, combined with the fact that advanced ovarian and breast cancer patients had high immune response rates while advanced prostate cancer patients had lower immune response rates, suggest that patients with a history of favorable responses to therapy, and in a state of minimal residual disease, are likely preferred candidates for DPX-0907 immunotherapy. These findings support the belief that DPX-0907 holds therapeutic potential in treating properly selected patients with either ovarian, breast or prostate cancer. The Company intends to leverage this information to guide future clinical studies of DPX-0907 and all immunotherapies incorporating its DepoVax adjuvanting technology.

“We believe that the breadth of positive data generated by this very first clinical study of DPX-0907 and the DepoVax technology provides support for the potential therapeutic value of both the product and the platform. Importantly, the valuable information that we’ve learned from this study, in terms of safety, immune response and patient profile, provides Immunovaccine with critical insight into how best to proceed with the clinical development of this novel approach to cancer immunotherapy,” said Marc Mansour, Ph.D., Immunovaccine’s chief science officer. “The timing of this publication is particularly exciting with the recent resurgence in interest in cancer immunotherapy and the presentation of promising data from various studies at the recent annual ASCO conference.”

About the DPX-0907 Phase I Clinical Trial
The completed DPX-0907 Phase I trial was an open-label, dose-escalation trial conducted at five centers in the U.S. with patients receiving three injections (0.25 mL or 1 mL doses) of the active immune therapy DPX-0907, three weeks apart. Safety was assessed in eleven patients in the 0.25 mL dose group and eleven patients in the 1 mL dose group. The immunogenicity results were based on an analysis of nine evaluable patients in the 0.25 mL dose group and nine evaluable patients in the 1 mL dose group.

The study met the primary objective of safety with overall results demonstrating that DPX-0907 is generally well tolerated by all patients and is considered safe at both dose levels with no vaccine related serious adverse effects reported. The study also met its secondary endpoint, demonstrating antigen-specific CD8+ T cell responses following vaccination. These safety and immunogenicity findings validate the proprietary DepoVax liposome-in-oil platform, which is designed to augment vaccine antigens by incorporating adjuvants and other vaccine enhancement features while simplifying the use of oil-based depot vaccines, through an emulsion-free approach.


About Immunovaccine
Immunovaccine Inc. applies its novel vaccine delivery platform to the development of vaccines for cancer therapy and infectious diseases. The Company’s DepoVax™ platform is a patented lipid delivery system that presents antigens plus adjuvant to the immune system for a prolonged period and has the potential to enhance immune responses. Immunovaccine has advanced its platform technology and proprietary cancer vaccine into Phase I human clinical trials and has demonstrated both safety and immunogenicity potential. The Company is also capitalizing on the broad potential of its delivery platform by creating new DepoVax-based vaccines through multiple development collaborations. In addition to the Company’s human health vaccine strategy, it continues to capture value from animal health vaccine applications. Immunovaccine has several key partnerships in the animal health sector including an agreement with Pfizer Animal Health, which has licensed the Company’s delivery technology platform to develop vaccines for livestock. Connect at www.imvaccine.com.
 

Tim Brons, Vice President
415-675-7402 [Office]; 646-319-8981 [Cell]
tbrons@vidacommunication.com

Posted: August 2012

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