A multicohort trial is currently underway, and the expansion will study a subcutaneous version of the vaccine in order to review adding sublingual boosts. In a second phase I study, the firms will examine adding an oral boost to the subcutaneous prime administration.

The expansions are due to positive results of recent data showing the bivalent vaccine resulted in potent stimulation of S- and N-specific T cells with a potent antibody release from memory B cells following viral challenge when an oral boost was added, the firms said. Also, the full immune system was activated by S and N proteins and resulted in complete viral clearance of SARS-CoV-2 in lung and nasal passages, they added.

ImmunityBio and NantKwest will enroll another 105 participants in U.S. trials this month at two sites in California. Based on the trial findings, the optimal combination of oral or sublingual boosts will be determined and entered into a phase II/III study.