VBI Vaccines Inc. announced interim data from the Phase 1 clinical study of its multivalent pan-coronavirus vaccine candidate, VBI-2901, which expresses the ancestral COVID-19, SARS, and MERS spike antigens. The Phase 1 clinical study enrolled 101 adults, aged 18-64 years who had received either two or three doses of a messenger RNA (mRNA) COVID-19 vaccine licensed by Health Canada, and assessed both one and two dose booster regimens of VBI-2901. Based on interim data, however, peak responses were achieved with only a single 10µg dose of VBI-2901.

Breadth of Immune Response All participants saw boosting and/or high neutralizing responses against a panel of COVID-19 variants, including Wuhan, Delta, Beta, Omicron BA.5, as well as multiple animal coronaviruses including bat and pangolin variants Participants with low baseline neutralization titers (geometric mean titer (GMT): 148 IU50/mL), who are at the highest risk of infection, saw the greatest vaccine-induced boosting effects across all variants tested at Day 28, after one dose, with increases of: 8.5x against Wuhan, 9.1x against Delta, 14.2x against Beta, and 5.8x against Omicron BA.5 Durability of Immune Response All participants who received one dose had enhanced persistence of neutralizing responses, with only about 25% reduction in GMT against Wuhan after 5 months vs. peak responses Similar enhanced durability trends were observed against all tested variants By comparison, a recently published study [Gilboa et al., 2022] evaluating immune responses after a third dose of a licensed mRNA vaccine in nearly 4,000 healthcare workers in Israel demonstrated an approximate 77% decline in GMT against Wuhan after 5 months vs. peak responses1 In the same study [Gilboa et al., 2022], durability trends against other variants, including Omicron, were seen to wane even more aggressively, with 4-fold to 10-fold lower neutralization titers within 4 months of the third dose About the Phase 1 Study The Phase 1 randomized, open-label study enrolled 101 subjects across three cohorts, randomized 1:1:1, to compare either two intramuscular doses of VBI-2901 at a low- (5µg) or high- (10µg) dose level, or one dose of VBI-2901 at the high-dose level (10µg) healthy adults age 18-64 who have previously received two or three immunizations with COVID-19 vaccines licensed by Health Canada.

Each participant had received their previous dose of a licensed COVID-19 vaccine at least six months prior to study enrollment.