Arexvy

The RSVPreF3 antigen in Arexvy is derived from the laboratory-adapted RSV-A A2 strain, stabilised in the pre-fusion conformation of the naturally occurring F protein for which both RSV-A and B subtypes share high amino acid sequence homology. The risk of developing RSV-associated lower respiratory tract disease (LRTD) increases with age and with presence of underlying comorbidities. Arexvy induces the functional humoral immune responses against the RSV-A and RSV-B subtypes and the antigen-specific cellular immune responses which contribute to protect against RSV-associated LRTD (see Immunogenicity of Arexvy in the Product Information).
In a Phase I/II clinical trial, formulation adjuvanted with AS01E showed the ability to induce RSVPreF3-specific CD4+ T cells in adults 60 to 80 years of age to levels similar to those observed in young adults, despite lower baseline levels in the older adults.
Nonclinical data show that AS01E induces a local and transient activation of the innate immune system. The adjuvant effect of AS01E is the result of interactions between MPL and QS-21 formulated in liposomes. This facilitates the recruitment and activation of antigen presenting cells carrying vaccine-derived antigens in the draining lymph node, which in turn leads to the generation of RSVPreF3-specific CD4+ T cells and induction of RSV-A and RSV-B neutralising antibody responses. In addition, RSVPreF3 formulated with AS01E can elicit specific binding antibodies directed to site Ø, a highly neutralising sensitive epitope, exposed only on the pre fusion conformation of the F protein.