A Multi-site, Phase I/II, 2-Part, Dose-Escalation Trial Investigating the Safety and Immunogenicity of Four Prophylactic SARS-CoV-2 RNA Vaccines Against COVID-2019 Using Different Dosing Regimens in Healthy and Immunocompromised Adults

This trial has two parts. Part A and Part B. Due to changes in the overall clinical
development plan, Part B will no longer be conducted. 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).

Part A is for dose ranging of four different vaccines (BNT162a1, BNT162b1, BNT162b2, and
BNT162c2) which will be undertaken with dose escalation and de-escalation plus the evaluation
of interim dose levels. It also includes dose ranging in older participants.

The vaccines BNT162a1, BNT162b1, BNT162b2, and BNT162c2 will be administered using a
Prime/Boost (P/B) regimen. The vaccine BNT162c2 will also be administered using a Single dose
(SD) regimen. Three additional cohorts aged from 18 to 85 years receiving BNT162b2 only.

BNT162b2 has entered a Phase II/III evaluation of efficacy, with the intent to support an
application for marketing authorization. The dosing regimen under investigation is two
BNT162b2 doses given ~21 d apart.