A Trial Investigating the Safety and Effects of Four BNT162 Vaccines Against COVID-19 in Healthy and Immunocompromised Adults

Originally, the study was planned to include two parts, i.e., Part A and Part B, however Part B was cancelled due to changes in the overall clinical development plan. The objectives originally described for Part B have been implemented in the ongoing development via a pivotal Phase I/II/III trial BNT162-02/C4591001 (ClinicalTrials.gov NCT: 04368728). The conducted Part A was a dose-finding part to investigate the optimal dose of four different vaccines (BNT162a1, BNT162b1, BNT162b2, and BNT162c2), allowing dose adjustments upwards and downwards in younger participants. Doses tested in older participants and expansion cohorts were chosen based on acceptability of dosing in younger participants. The vaccines BNT162a1, BNT162b1, BNT162b2, and BNT162c2 were administered using a Prime/Boost (P/B) regimen with two doses given \~21 days apart. The vaccine BNT162c2 was also administered using a Single dose (SD) regimen. Four additional expansion cohorts (cohorts 11, 12, 13, and 14) aged from 18 to 85 years received BNT162b2 using a P/B regimen only. In cohort 11, participants received BNT162b2 using one 3 μg prime dose (Dose 1) and one 30 μg boost dose (Dose 2) of BNT162b2. Participants in cohorts 12, 13, and 14 received two doses of BNT162b2 30 µg, each.