STREPTOCOCCUS AGALACTIAE, SEROTYPE IA, CAPSULAR POLYSACCHARIDE, CONJUGATED TO CRM197

Table of contents

• What is Streptococcus Agalactiae?
• How does Streptococcus Agalactiae work?
• Which conditions is Streptococcus Agalactiae being studied for?
• How is Streptococcus Agalactiae given?
• What do the clinical trials show?
• Who can take part in these trials?

What is streptococcus Agalactiae?

Streptococcus Agalactiae, also known as group B streptococcus (GBS) serotype Ia, is a capsular polysaccharide from the surface of the GBS bacterium. In the vaccine studied here, this polysaccharide is conjugated to CRM197, a non-toxic carrier protein used in several licensed vaccines to strengthen the immune response. The full substance name is STREPTOCOCCUS AGALACTIAE, SEROTYPE IA, CAPSULAR POLYSACCHARIDE, CONJUGATED TO CRM197. In the registered trial, this substance is one component of a six-valent polysaccharide conjugate vaccine called GBS6, which includes serotypes Ia, Ib, II, III, IV, and V.^[1] Streptococcus Agalactiae is an investigational substance with no marketing authorisation in these records.

How does streptococcus Agalactiae work?

The capsular polysaccharide from GBS serotype Ia is the part of the bacterium that the immune system can recognise. Conjugating this polysaccharide to the CRM197 carrier protein helps the immune system mount a stronger antibody response, particularly in pregnant women whose antibodies can cross the placenta. When a pregnant woman receives the vaccine, her body produces antibodies against the GBS capsular polysaccharides, including serotype Ia. These antibodies can pass to the infant before birth, providing passive protection against invasive GBS disease in the first months of life.^[1]

Which conditions is streptococcus Agalactiae being studied for?

• Group B streptococcus (GBS) disease — an infection caused by the GBS bacterium that can cause serious illness, including bloodstream infection and meningitis, in newborn infants.^[1]

How is streptococcus Agalactiae given?

In the registered trial, the GBS6 vaccine containing Streptococcus Agalactiae serotype Ia polysaccharide is given as an intramuscular injection. The trial records list the pharmaceutical form as a solution for injection.^[1]

What do the clinical trials show?

One clinical trial is registered for this substance. The study is a Phase 3 interventional trial with the identifier NCT07160244, currently in Authorised status, meaning it has received approval but has not yet started recruiting participants.^[1] The trial plans to enrol 12,000 healthy pregnant women and their infants.^[1]

The primary outcomes include prespecified local reactions such as redness, swelling, and pain at the injection site, as well as systemic events including fever, nausea, vomiting, diarrhoea, headache, fatigue, muscle pain, and joint pain.^[1] The study also measures adverse events, serious adverse events, medically attended adverse events, and adverse events of special interest.^[1] A key efficacy measure is the GBS serotype-specific anti-CPS IgG antibody concentration measured at birth in infant participants.^[1] The trial aims to evaluate whether the antibody levels induced by maternal vaccination are predicted to provide protection against invasive GBS early-onset disease (EOD) and late-onset disease (LOD) caused by the six vaccine serotypes.^[1]

Who can take part in these trials?

The Phase 3 trial enrols healthy pregnant women and their infants. The study is designed to assess the safety and tolerability of GBS6 in maternal participants and to assess the safety of maternal immunisation in infant participants born to pregnant individuals who were vaccinated with GBS6 during pregnancy.^[1]