A Phase 2 Study to Evaluate the Safety, Tolerability, and Immune Response of AFX3772 Vaccine in Healthy Infants

A Phase 2, Randomized, Double-blind, Multi-dose, Dose Finding Study to Evaluate the Safety, Tolerability and Immunogenicity of AFX3772 Compared With PCVs in Healthy Infants

This is a Phase 2 clinical study to support the use of AFX3772 in healthy infants for the prevention of pneumococcal disease. The purpose of this study is to determine the safety, tolerability, and immunogenicity of 3 different formulations of AFX3772 compared with Prevnar 13 (PCV13) and Prevnar 20 (PCV).

Part 1 is the dose escalation, lead-in portion of the study in which infants at each dose level will be randomized 3:1 in sequential cohorts of increasing doses of AFX3772 or PCV13.

In Part 2, infants will be randomized to receive either one of two dose levels of AFX3772 or PCV20.

Inclusion Criteria:

• Is a full-term infant approximately 2 months of age at time of obtaining the informed consent.

Exclusion Criteria:

• Had prior administration of any pneumococcal vaccine.
• Has a known or suspected hypersensitivity to AFX3772, PCV13, PCV20 or any components of the formulations used.
• Has a known or suspected immunodeficiency or other conditions associated with immunosuppression that may require immunosuppressive drugs. In addition, the participant's biological mother has known HIV infection or known to be hepatitis B surface antigen positive.
• Has any clinically significant allergic condition or history prior to the first vaccination for primary immunization series.
• Has a history of microbiologically proven invasive disease caused by S. pneumoniae.
• Has received immunoglobulins.
• Has a bleeding diathesis or condition associated with prolonged bleeding that would contraindicate intramuscular injection.
• Has received systemic corticosteroids for a period of more than 14 days and has not completed the treatment for at least 30 days before study vaccine.