VBI Vaccines Announces Positive Final Phase 1 Study Results of Preventative CMV Vaccine
VBI Vaccines announced positive final top-line results from the randomized, placebo-controlled Phase 1 study of VBI-1501, the company’s prophylactic cytomegalovirus (CMV) vaccine candidate. VBI-1501 was developed using the company’s proprietary enveloped virus-like particle (eVLP) technology and presents a modified form of the glycoprotein B (gB) found on CMV. The final Phase 1 study results demonstrated that VBI-1501 was safe and well-tolerated at all doses. The highest dose of VBI-1501, 2.0μg, elicited protective CMV-neutralizing antibodies against fibroblast cell infection in 100% of subjects after the third vaccination, inducing titers comparable to those observed in patients protected as a result of natural infection. Neutralizing antibodies against epithelial cell infection were also seen in 31% of subjects receiving the same dose.
“These clinical results further demonstrate that our eVLP technology is a highly potent platform for antigen delivery that is safe and well-tolerated,” said Jeff Baxter, president and CEO of VBI. “We are extremely excited that we were able to show a robust immunologic response at a dose that is one-tenth the amount of other organizations’ CMV vaccine candidates. We believe this speaks to the unique antigen presentation capabilities of the eVLP platform. We look forward to the next stage of clinical development of VBI-1501 as we work diligently to address the significant unmet needs in CMV infection, a leading cause of birth defects worldwide.”
Final immunogenicity data from VBI’s Phase 1 study included gB antibody binding titers and neutralizing antibody seroconversion in both fibroblast and epithelial cells, two cell types CMV infects that are widely used to gauge the potency of CMV vaccine candidates.
- VBI-1501 induced gB antibody binding titers at all dose levels, with clear evidence of dose-dependent boosting after each vaccination.
- In fibroblast cells, the highest dose of VBI-1501 (0μg of gB-G content with alum) demonstrated an 85% neutralizing antibody seroconversion rate after two vaccinations and 100% after three vaccinations. Neutralizing antibody titers were comparable to those from CMV-positive controls (immunity induced by natural infection).
- In epithelial cells, which have historically been the much harder cell type to protect against infection, the highest dose of VBI-1501 with alum demonstrated a 31% neutralizing antibody seroconversion rate after three vaccinations, up from 17% after two vaccinations.
David E. Anderson, Ph.D., VBI Chief Scientific Officer, commented, “Given that CMV infects many cell types, one objective of our trial was to induce functional, neutralizing antibody responses that could block infection in multiple cell types. We are pleased to see activity against both fibroblast and epithelial cell infection, and expect that higher doses of VBI-1501 should further improve upon these positive and encouraging results.”
Joanne Langley, M.D., an Associate Director with the Canadian Center for Vaccinology located at Dalhousie University, the IWK Health Centre, and the Nova Scotia Health Authority, and Principal Investigator of the study further commented, “The safety profile of this vaccine is such that there is little concern about evaluating VBI-1501 at higher doses in the next stage of clinical development. With the functional activity we’ve seen, even at a low dose, these results are incredibly encouraging.”