INOVIO announced that data from a Phase 1b trial evaluating INO-4201 as an Ebola booster vaccine candidate for rVSV-ZEBOV (Ervebo) (NCT04906629) was presented at the 33rdEuropean Congress of Clinical Microbiology and Infectious Diseases (ECCMID). Dr. Angela Huttner, Infectious Disease Consultant, Geneva University Hospitals, and lead investigator for the trial, gave the oral presentation. In February 2023, INOVIO announced positive initial results from the Phase 1b trial that evaluated INO-4201 as a booster in healthy adult participants who previously received a single injection of Ervebo.

These initial results showed that INO-4201 was well-tolerated and boosted humoral responses in 100% (36 of 36) of treated participants. Today, the full data set was presented at ECCMID, including new humoral and cellular response data that indicates the potential of INO-4201 to restore antibody titers to levels thought to be required to provide protection against Zaire ebolavirus infection. These new data include the assessment of binding antibodies showing that all 36 vaccine recipients responded to the boost: Binding antibodies were assessed via ELISA at the Galveston National Laboratory, using an assay designed by director Dr. Gary Kobinger.

Geometric mean titers (GMT) at baseline were lower in vaccine recipients than in placebo recipients (157.8 [95% CI 87.2-285.5] versus 712.7 [388.0-1309.3], p=.022). In vaccine recipients, however, GMTs rose significantly after boosting for each time point measured, peaking at week 2 (GMT 1514.8 [95% CI 1215-1888.0] versus 578.5 [95% CI 262.0-1278.9] p=.002) and remaining significantly higher at week 4 (1236.5 [957.9-1596.0] versus 670.0 [CI 95% 347.3-1292.4], p=.029). Mean neutralizing antibody titers in vaccine recipients rose from 23.4 [95% CI -12.5-23.6] to 62.8 [95% CI 23.6-101.9] by week 4 and remained high and constant until the end of the 24-week trial period (50.4 [95% CI 15.1-85.8).

Neutralizing antibodies were assessed with EBOV GP pseudo-typed particles. Cellular responses observed in participants included an increase in Th1 cytokine production (IFN?, IL2, TNFa) from CD4+ and CD8+ T cells following boost with INO-4201. The Phase 1b trial for INOVIO's vaccine candidate, INO-4201, was spearheaded by Global Urgent and Advanced Research and Development (GuardRX), sponsored by Geneva University Hospitals, and funded by the U.S. Defense Advanced Research Projects Agency.

INO-4201 is INOVIO's DNA vaccine targeting Zaire Ebola virus (ZEBOV) glycoprotein (GP), designed to prevent ZEBOV infection. INO-4201 encodes for a synthetic consensus antigen that encompasses ZEBOV genetic variability from various outbreak strains to broaden immune coverage for divergent ZEBOV virus variants.