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.

Study Overview

• Status: Completed
• Conditions: Pneumococcal Infections; Pneumonia, Pneumococcal; Pneumonia, Bacterial
• Intervention / Treatment: Biological: AFX3772; Biological: Prevnar 13; Biological: Prevnar 20

• Study Type: Interventional
• Enrollment (Actual): 388
• Phase: Phase 2

Contacts and Locations

Study Locations

• Puerto Rico
  • Bayamón, Puerto Rico, 960
    • GSK Investigational Site
  • Caguas, Puerto Rico, 00725
    • GSK Investigational Site
  • Ponce, Puerto Rico, 00716
    • GSK Investigational Site
  • San Juan, Puerto Rico, 00935-6528
    • GSK Investigational Site
• United States
  • Arkansas
    • Jonesboro, Arkansas, United States, 72401
      • GSK Investigational Site
  • California
    • Los Angeles, California, United States, 90057
      • GSK Investigational Site
  • Florida
    • Miami, Florida, United States, 33184
      • GSK Investigational Site
    • Pensacola, Florida, United States, 32503
      • GSK Investigational Site
    • Saint Augustine, Florida, United States, 32086
      • GSK Investigational Site
    • Tampa, Florida, United States, 33613
      • GSK Investigational Site
  • Idaho
    • Nampa, Idaho, United States, 83702
      • GSK Investigational Site
  • Kentucky
    • Bardstown, Kentucky, United States, 40004
      • GSK Investigational Site
    • Lexington, Kentucky, United States, 40517
      • GSK Investigational Site
    • Louisville, Kentucky, United States, 40291
      • GSK Investigational Site
  • Louisiana
    • Covington, Louisiana, United States, 70433
      • GSK Investigational Site
    • Haughton, Louisiana, United States, 71037
      • GSK Investigational Site
    • Lafayette, Louisiana, United States, 70508
      • GSK Investigational Site
    • New Orleans, Louisiana, United States, 70119
      • GSK Investigational Site
  • Minnesota
    • Mankato, Minnesota, United States, 56001
      • GSK Investigational Site
  • Montana
    • Missoula, Montana, United States, 59804
      • GSK Investigational Site
  • Nebraska
    • Hastings, Nebraska, United States, 68901
      • GSK Investigational Site
  • Ohio
    • Cincinnati, Ohio, United States, 45245
      • GSK Investigational Site
  • Oklahoma
    • Tulsa, Oklahoma, United States, 74104
      • GSK Investigational Site
  • Pennsylvania
    • Cranberry Township, Pennsylvania, United States, 16006
      • GSK Investigational Site
    • Jefferson Hills, Pennsylvania, United States, 15025
      • GSK Investigational Site
    • N. Huntingdon, Pennsylvania, United States, 15642
      • GSK Investigational Site
    • Pittsburgh, Pennsylvania, United States, 15213
      • GSK Investigational Site
    • Pittsburgh, Pennsylvania, United States, 15217
      • GSK Investigational Site
    • Pittsburgh, Pennsylvania, United States, 15234
      • GSK Investigational Site
  • South Carolina
    • Charleston, South Carolina, United States, 29407
      • GSK Investigational Site
    • Greenville, South Carolina, United States, 29607
      • GSK Investigational Site
    • Spartanburg, South Carolina, United States, 29301
      • GSK Investigational Site
  • Texas
    • Brownsville, Texas, United States, 78520
      • GSK Investigational Site
    • Dallas, Texas, United States, 75230
      • GSK Investigational Site
    • Dickinson, Texas, United States, 77539
      • GSK Investigational Site
    • Houston, Texas, United States, 77087
      • GSK Investigational Site
    • Houston, Texas, United States, 77065
      • GSK Investigational Site
    • Houston, Texas, United States, 77077
      • GSK Investigational Site
    • McAllen, Texas, United States, 78504
      • GSK Investigational Site
    • Richmond, Texas, United States, 77469
      • GSK Investigational Site
  • Utah
    • Layton, Utah, United States, 84041
      • GSK Investigational Site
    • Roy, Utah, United States, 84067
      • GSK Investigational Site
    • Salt Lake City, Utah, United States, 84107
      • GSK Investigational Site
    • South Jordan, Utah, United States, 84095
      • GSK Investigational Site
    • Syracuse, Utah, United States, 84075
      • GSK Investigational Site
  • Virginia
    • Norfolk, Virginia, United States, 68701
      • GSK Investigational Site

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 month to 2 months (Child)
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Quadruple

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Part 1 Group 1; Infants are scheduled to receive up to three doses of 1 mcg AFX3772 as part of the primary series, followed by a booster dose. Those who do not receive the planned AFX3772 dose are administered PCV13 as standard of care (SOC).	Biological: AFX3772; AFX3772 administered intramuscularly.; Biological: Prevnar 13; PCV13 administered intramuscularly.; Other Names: PCV13
Experimental: Part 1 Group 2; Infants are scheduled to receive up to three doses of 2 mcg AFX3772 as part of the primary series, followed by a booster dose. Those who do not receive the planned AFX3772 dose are administered PCV13 as SOC.	Biological: AFX3772; AFX3772 administered intramuscularly.; Biological: Prevnar 13; PCV13 administered intramuscularly.; Other Names: PCV13
Experimental: Part 1 Group 3; Infants are scheduled to receive up to three doses of 5 mcg AFX3772 as part of the primary series, followed by a booster dose. Those who do not receive the planned AFX3772 dose are administered PCV13 as SOC.	Biological: AFX3772; AFX3772 administered intramuscularly.; Biological: Prevnar 13; PCV13 administered intramuscularly.; Other Names: PCV13
Active Comparator: Part 1 Group 4; PCV13 administered intramuscularly within 12 months.	Biological: Prevnar 13; PCV13 administered intramuscularly.; Other Names: PCV13
Experimental: Part 2 Group 5; Infants are scheduled to receive up to three doses of 2 mcg AFX3772 as part of the primary series, followed by a booster dose. Those who do not receive the planned AFX3772 dose are administered PCV20 as SOC.	Biological: AFX3772; AFX3772 administered intramuscularly.; Biological: Prevnar 20; PCV 20 administered intramuscularly.; Other Names: PCV20
Experimental: Part 2 Group 6; Infants are scheduled to receive up to three doses of 5 mcg AFX3772 as part of the primary series, followed by a booster dose. Those who do not receive the planned AFX3772 dose are administered PCV20 as SOC.	Biological: AFX3772; AFX3772 administered intramuscularly.; Biological: Prevnar 20; PCV 20 administered intramuscularly.; Other Names: PCV20
Active Comparator: Part 2 Group 7; PCV20 administered intramuscularly within 12 months.	Biological: Prevnar 20; PCV 20 administered intramuscularly.; Other Names: PCV20

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants with solicited injection site events	The assessed solicited injection site events are tenderness, redness/erythema and swelling.	Day 1 through Day 7 post-vaccination
Percentage of participants with solicited systemic events	The assessed solicited systemic events are irritability, fever, decrease of appetite, increased sleep, and decrease in sleep.	Day 1 through Day 7 post-vaccination
Percentage of participants with AEs	An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study intervention.	Day 1 through Day 30
Percentage of participants with serious adverse events (SAEs)	An SAE is any untoward medical occurrence that, at any dose, results in death, is life-threatening, requires in patient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity. Medical or scientific judgment will be exercised by the investigator in deciding whether SAE reporting is appropriate in other situations such as significant medical events that may jeopardize the participant or may require medical or surgical intervention to prevent one of the other outcomes listed in the above definition.	Day 1 through 6 months post dose three

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of participants with a pneumococcal serotype-specific Immunoglobulin G (IgG) concentration of greater than or equal to (>=) 0.35 μg/mL or corresponding threshold	Immunological responses were assessed in terms of percentage of participants with a pneumococcal serotype-specific IgG concentration >= 0.35 μg/mL or corresponding threshold.	30 days post-dose two, 30 days post-dose three
Geometric mean concentration for serotype-specific IgG	Immunological responses were assessed in terms of IgG GMCs and expressed as titers.	30 days post-dose two, 30 days post-dose three

Collaborators and Investigators

• Sponsor: GlaxoSmithKline
• Collaborators: Affinivax, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): June 16, 2022
• Primary Completion (Actual): September 18, 2025
• Study Completion (Actual): September 18, 2025

Study Registration Dates

• First Submitted: June 3, 2022
• First Submitted That Met QC Criteria: June 7, 2022
• First Posted (Actual): June 9, 2022

Study Record Updates

• Last Update Posted (Estimated): October 21, 2025
• Last Update Submitted That Met QC Criteria: October 17, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Pneumonia; Infections; Streptococcal Infections; Pneumonia, Pneumococcal
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Respiratory Tract Diseases; Lung Diseases; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Pneumonia; Infections; Pneumococcal Infections; Pneumonia, Pneumococcal; Pneumonia, Bacterial; Streptococcal Infections; Immunologic Factors; Physiological Effects of Drugs; 13-valent pneumococcal vaccine
• Other Study ID Numbers: 219651; 2023-000423-36 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: GSK will assess requests from qualified researchers for anonymized individual patient-level data and related study documents. Data sharing is subject to certain criteria, conditions, and exceptions. For further information, refer to https://www.gsk-studyregister.com/About_GSK_Patient_Level_Data_Sharing_Final_13July2023.pdf
• IPD Sharing Time Frame: Anonymized IPD will be made available within 6 months of publication of primary, key secondary and safety results for studies in product with approved indication(s) or terminated asset(s) across all indications.
• IPD Sharing Access Criteria: Anonymized IPD is shared with researchers whose proposals are approved by an Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension may be granted, when justified, for up to 6 months.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No