Respiratory Syncytial Virus, Glycoprotein F, Recombinant, Stabilised In The Pre-Fusion Conformation, Adjuvanted With As01E

This article summarizes several clinical trials investigating Arexvy, a new vaccine developed by GlaxoSmithKline to prevent respiratory syncytial virus (RSV) infections in adults. Arexvy contains a recombinant RSV protein called PreF3 and an adjuvant system called AS01E to boost immune responses. The trials are evaluating the safety, immune responses, and effectiveness of Arexvy in different adult populations, including healthy older adults, adults with increased risk factors, and immunocompromised patients. Key aspects being studied include optimal dosing schedules, co-administration with other vaccines, and protection against RSV disease.

What is Arexvy?
How Does Arexvy Work?
Who is Arexvy For?
Effectiveness
Dosing
Safety and Side Effects
Ongoing Research

What is Arexvy?

Arexvy is a new vaccine developed to prevent respiratory syncytial virus (RSV) infections in adults. It was created by GlaxoSmithKline and received approval for use in the European Union in 2023^[1]. The vaccine’s full name is “Respiratory Syncytial Virus Vaccine (recombinant, adjuvanted)” and it is also known by the code name RSVPreF3 OA^[2].

RSV is a common respiratory virus that usually causes mild, cold-like symptoms. However, it can be serious for infants and older adults. RSV is a leading cause of hospitalization in infants and can cause severe illness in older adults, especially those with chronic heart or lung disease^[1].

How Does Arexvy Work?

Arexvy is a subunit vaccine, which means it contains specific parts of the RSV virus rather than the whole virus. Specifically, it contains:

A recombinant form of the RSV F protein, which is found on the surface of the virus
An adjuvant called AS01E, which helps boost the immune response to the vaccine

The vaccine works by stimulating the body’s immune system to produce antibodies against the RSV F protein. These antibodies can then recognize and fight off RSV if the vaccinated person is exposed to the virus in the future^[2].

Who is Arexvy For?

Arexvy is currently approved in the European Union for adults 60 years of age and older^[1]. This age group is at higher risk for severe RSV disease.

Research is ongoing to evaluate the vaccine’s use in other populations, including:

Adults 18-49 years old who are at increased risk for RSV disease due to underlying medical conditions^[3]
Immunocompromised patients aged 18 years and older^[4]

Effectiveness

Clinical trials have shown that Arexvy is effective at stimulating an immune response against RSV. The vaccine produces:

Neutralizing antibodies against both major subtypes of RSV (RSV-A and RSV-B)
RSVPreF3-specific binding antibodies
RSV-specific T cell responses

In adults 60 years and older, a single dose of Arexvy produced a strong immune response that persisted for at least 12 months after vaccination^[5].

Dosing

Arexvy is given as an intramuscular injection, typically in the upper arm. The standard dose is 0.5 mL^[6].

For most adults 60 years and older, a single dose is recommended. However, some ongoing studies are evaluating different dosing schedules, including:

Annual revaccination
Revaccination after 2-3 years
Two-dose primary series for certain immunocompromised patients

The optimal timing and frequency of vaccination are still being determined through ongoing research^[7].

Safety and Side Effects

Clinical trials have shown that Arexvy is generally safe and well-tolerated. The most common side effects are similar to those seen with other vaccines and include:

Pain at the injection site
Fatigue
Headache
Muscle pain

These side effects are usually mild to moderate and resolve within a few days^[3].

As with any vaccine, there is a small risk of severe allergic reaction (anaphylaxis). People with a history of severe allergic reactions to any component of Arexvy should not receive the vaccine^[6].

Ongoing Research

Several clinical trials are currently underway to further evaluate Arexvy, including:

Studies on long-term effectiveness and the potential need for booster doses
Research on co-administration with other vaccines, such as COVID-19 vaccines
Trials in specific populations like immunocompromised patients
Studies to determine the optimal vaccination schedule

These ongoing studies will help provide more information on how to best use Arexvy to protect against RSV^[5].

Trial Number	Population	Key Objectives	Dosing Schedule
2023-503951-81-00	Lung and kidney transplant recipients ≥18 years, healthy adults ≥50 years	Evaluate immune response and safety, compare 1 vs 2 doses in transplant recipients	1 or 2 doses
2023-509455-13-00	Adults ≥60 years	Evaluate immunogenicity, safety, and occurrence of RSV-associated respiratory illness	Single dose
2023-509762-38-00	Adults ≥60 years	Evaluate immune response and safety of different revaccination schedules	Initial dose + revaccination at various intervals
2023-510190-34-00	Adults 18-49 years at increased risk, adults ≥60 years	Compare immune response in at-risk adults to older adults	Single dose
2023-510196-59-00	Adults ≥50 years	Evaluate co-administration with COVID-19 mRNA vaccine	Single dose (with or without COVID-19 vaccine)
2024-512291-34-00	Adults ≥60 years	Evaluate long-term immune responses and different revaccination schedules	Initial dose + various revaccination schedules
2024-513187-25-00	Immunocompromised patients ≥18 years, healthy adults ≥60 years	Evaluate immune response and safety in immunocompromised patients	1 or 2 doses for immunocompromised, 1 dose for healthy controls

Trial Number

Population

Key Objectives

Dosing Schedule

2023-503951-81-00

Lung and kidney transplant recipients ≥18 years, healthy adults ≥50 years

Evaluate immune response and safety, compare 1 vs 2 doses in transplant recipients

1 or 2 doses

2023-509455-13-00

Adults ≥60 years

Evaluate immunogenicity, safety, and occurrence of RSV-associated respiratory illness

Single dose

2023-509762-38-00

Adults ≥60 years

Evaluate immune response and safety of different revaccination schedules

Initial dose + revaccination at various intervals

2023-510190-34-00

Adults 18-49 years at increased risk, adults ≥60 years

Compare immune response in at-risk adults to older adults

Single dose

2023-510196-59-00

Adults ≥50 years

Evaluate co-administration with COVID-19 mRNA vaccine

Single dose (with or without COVID-19 vaccine)

2024-512291-34-00

Adults ≥60 years

Evaluate long-term immune responses and different revaccination schedules

Initial dose + various revaccination schedules

2024-513187-25-00

Immunocompromised patients ≥18 years, healthy adults ≥60 years

Evaluate immune response and safety in immunocompromised patients

1 or 2 doses for immunocompromised, 1 dose for healthy controls

Ongoing Clinical Trials on Respiratory Syncytial Virus, Glycoprotein F, Recombinant, Stabilised In The Pre-Fusion Conformation, Adjuvanted With As01E

Glossary

Respiratory Syncytial Virus (RSV): A common respiratory virus that can cause mild, cold-like symptoms in adults and older children, but can be serious in infants and older adults. It's a major cause of lower respiratory tract infections.
Arexvy: The brand name for GSK's new RSV vaccine containing a recombinant RSV F protein stabilized in its pre-fusion form (PreF3) and adjuvanted with AS01E.
PreF3: The main component of the Arexvy vaccine – a recombinant form of the RSV F (fusion) protein that's stabilized in its pre-fusion conformation to induce stronger antibody responses.
AS01E: An adjuvant system used in Arexvy to enhance the immune response to the vaccine. Adjuvants are substances added to vaccines to improve their effectiveness.
Immunogenicity: The ability of a substance, such as a vaccine, to provoke an immune response in the body. In these trials, it refers to the antibody and cellular immune responses induced by Arexvy.
Neutralizing antibodies: Antibodies that can bind to a virus and prevent it from infecting cells or replicating. The levels of RSV-specific neutralizing antibodies are a key measure of Arexvy's effectiveness.
Seroresponse: A significant increase in antibody levels following vaccination, often defined as a 4-fold or greater rise in antibody titers.
Cellular immune response: The activation of immune cells, particularly T cells, in response to a vaccine or infection. This is measured by looking at RSV-specific CD4+ and CD8+ T cells in some of the Arexvy trials.
Adverse event (AE): Any unfavorable medical occurrence in a clinical trial participant, whether or not it's caused by the study treatment. These are carefully monitored and recorded in vaccine trials.
Serious Adverse Event (SAE): An adverse event that results in death, is life-threatening, requires hospitalization, causes significant disability, or is otherwise medically significant.
Potential Immune-Mediated Disease (pIMD): A group of conditions or symptoms that may be related to the immune system and are monitored closely in vaccine trials as events of special interest.

References

http://clinicaltrials.eu/trial-id/2023-509455-13-00
http://clinicaltrials.eu/trial-id/2023-503951-81-00
http://clinicaltrials.eu/trial-id/2023-510190-34-00
http://clinicaltrials.eu/trial-id/2024-513187-25-00
http://clinicaltrials.eu/trial-id/2023-509762-38-00
http://clinicaltrials.eu/trial-id/2023-510196-59-00
http://clinicaltrials.eu/trial/study-on-the-safety-and-immune-response-of-rsvpref3-vaccine-for-respiratory-syncytial-virus-in-adults-aged-60-and-above/

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