Positive Interim Phase 1 Data for DepoVax™-based Respiratory Syncytial Virus (RSV) Vaccine Candidate

6 July 2016

VIB-UGent research at the basis of this vaccine candidate ​

Immunovaccine Inc. (“Immunovaccine” or the “company”) (TSX: IMV; OTCQX: IMMVF), a clinical stage vaccine and immunotherapy company, announced that a team of investigators has completed an interim analysis of the safety and immunogenicity of its DepoVax™ prophylactic respiratory syncytial virus (RSV) vaccine candidate (DPX-RSV) in a Phase 1 clinical trial in healthy older adult volunteers. The safety analysis indicates that the DPX-RSV was well tolerated among all study participants, with no serious adverse events (SAEs) recorded. Furthermore, immunogenicity data supported DPX-RSV’s ability to generate a relevant immune response; the vaccine candidate obtained antigen-specific antibody responses in 75 percent of subjects vaccinated with the lower dose, and 100 percent of those vaccinated with the higher dose.

“Having the interim DPX-RSV data in hand marks a critical milestone for Immunovaccine. It represents our first clinical demonstration, outside of cancer trials, of the ability of DepoVax™-based vaccines to generate relevant immune responses in humans,” said Frederic Ors, Immunovaccine’s Chief Executive Officer.  “Deploying DepoVax™ in key areas of infectious disease remains a cornerstone of our strategy. We are encouraged by this data and look forward to continuing to explore the ways in which DepoVax™ can positively impact treatment developments in areas of unmet medical need in infectious diseases, including RSV.”

Principal Investigator Joanne Langley, BA, MD MSc FRCPC, led the study, which was conducted at the Canadian Center for Vaccinology (CCfV) and funded in an industry-academic collaboration by the Canadian Institutes of Health Research and Immunovaccine. The DPX-RSV trial included 40 healthy older adult volunteers and two dose cohorts, with 20 subjects in each cohort. Investigators analyzed the safety and immune response data of all participants up to study day 84.

Immunovaccine’s vaccine delivery approach focuses on targeting the ectodomain of the SH protein of RSV. Ectodomains are the parts of the protein exposed on the surface of the cell or virus. Prior preclinical research related to this study conducted by VIB and Ghent University scientists showed that antibody responses against the SH ectodomain were protective in animal models.

Targeting the SH antigen is a significant differentiator from other RSV vaccine programs for two reasons: 
1. Typical RSV vaccine efforts are focused on targeting the F and G proteins of the virus. However, people can remain susceptible to RSV infection even when they exhibit high levels of antibodies that target the F and G antigens.  

2. During RSV infection, infected cells are shed into the respiratory tract. If not cleared by the immune system, this process can cause airway obstruction and complications that linger post-infection. Immune responses targeting SH antigen were able to recognize the target protein on the virally infected cells, and were functional in activating immune mechanisms that may act to clear infected cells from the airways.

“We are pleased that the interim data from this study indicates that DPX-RSV is generally well-tolerated, and induces a robust immune response,” said Dr. Langley. “To the best of our knowledge, this is the first clinical-phase demonstration of a vaccine targeting the SH antigen and we believe that this analysis provides the rationale to continue clinical testing DPX-RSV in future human trials.”

“It is very rewarding to see that the basic research findings for an RSV vaccine candidate that was developed in my group at VIB and Ghent University contributed to this first-in-man study,” said Dr. Saelens, group leader at VIB and Ghent University (Ghent Belgium). “SH ectodomain-specific antibody responses can clearly be induced in humans by DPX-RSV and our results suggest that these antibodies can exert an anti-RSV effect.”

“This is a validating study for Immunovaccine,” stated Marianne Stanford, PhD, Director of Research at Immunovaccine. “It indicates that our first infectious disease vaccine candidate, DPX-RSV, exhibits unique features that both address unmet medical need related to the RSV virus, and also overcomes limitations of other vaccine candidates in development. This creates a potential benefit for future patients as well as a competitive advantage that will drive value to our investors.”

Immunovaccine has exclusive worldwide licenses on applications that target the SH ectodomain antigen in RSV.

Xavier Saelens & Bert Schepens