In short
PF-07831695 is an investigational vaccine being studied to protect against pneumococcal infections, a type of bacterial infection that can cause pneumonia and other serious illnesses. It is a pneumococcal polysaccharide conjugate vaccine given by intramuscular injection. One completed Phase 2 trial in 100 healthy toddlers has assessed its safety and immunogenicity, while the broader research programme includes larger Phase 3 studies in infants and children.
Key points
- PF-07831695 is an investigational pneumococcal conjugate vaccine developed by Pfizer.
- It is given as a 0.5 ml intramuscular injection in a suspension for injection.
- A Phase 2 trial in 100 healthy toddlers aged 11 to 15 months has been completed.
- The Phase 2 trial measured local reactions, systemic events, adverse events and serious adverse events.
- PF-07831695 has no marketing authorisation and remains an investigational substance.
- The completed trial compared PF-07831695 with Synflorix, an authorised pneumococcal vaccine.
What is PF-07831695?
PF-07831695 is an investigational pneumococcal polysaccharide conjugate vaccine. It is classified in the registry as a structurally diverse substance of vaccine origin, and its therapeutic area covers bacterial infections and mycoses as well as respiratory tract diseases. The substance is supplied by Pfizer Inc. and has no marketing authorisation in the product records, meaning it is still an investigational vaccine. In the completed Phase 2 trial, PF-07831695 is described as a monovalent pneumococcal conjugate candidate, indicating that it targets a single pneumococcal serotype.
How does PF-07831695 work?
Pneumococcal conjugate vaccines work by linking pneumococcal polysaccharides to a carrier protein, which helps the immune system recognise and respond to the bacteria. PF-07831695 is a monovalent pneumococcal conjugate candidate, meaning it is designed to target one specific pneumococcal serotype. In the same trial, the comparison arm included a pneumococcal polysaccharide serotype 3 conjugated to CRM197, a carrier protein commonly used in conjugate vaccines. The trial measured immunogenicity, which refers to the ability of the vaccine to generate an immune response.
Which conditions is PF-07831695 studied for?
PF-07831695 is being studied for the prevention of pneumococcal infections. The registry places it in the therapeutic areas of bacterial infections and mycoses and respiratory tract diseases.
- Pneumococcal infections — infections caused by the bacterium Streptococcus pneumoniae, which can lead to pneumonia, meningitis and bloodstream infections. The completed Phase 2 trial enrolled healthy toddlers to assess the safety and immunogenicity of PF-07831695 in this condition.
How is PF-07831695 given?
PF-07831695 is formulated as a suspension for injection and is given by intramuscular use. In the completed Phase 2 trial, the dose was 0.5 ml administered as part of a 2-dose series in children aged 11 to 15 months.
What do the clinical trials show?
One completed Phase 2 trial has evaluated PF-07831695. The trial enrolled 100 healthy toddlers aged 11 to 15 months and compared PF-07831695 with Synflorix, an authorised pneumococcal polysaccharide conjugate vaccine. The primary outcomes measured prompted local reactions such as redness, swelling and pain at the injection site, prompted systemic events including fever, decreased appetite, drowsiness and irritability, as well as adverse events and serious adverse events. The trial status is completed.
The trial included multiple arms. In addition to PF-07831695, separate arms received Synflorix and a pneumococcal polysaccharide serotype 3 conjugated to CRM197 adsorbed on aluminium phosphate. The study was designed to describe the safety profile of the monovalent pneumococcal conjugate candidate when administered as a 2-dose series.
What side effects are known?
The registry records for the completed Phase 2 trial list the safety outcomes that were measured, but do not report results. These outcomes included prompted local reactions at the injection site, prompted systemic events, adverse events and serious adverse events. No supplementary sources describing the side effect profile of PF-07831695 were provided.