Drug Overview
ChAd155-RSV is a chimpanzee-derived adenovector vaccine encoding the F, N, and M2-1 proteins. The vaccine is in Phase II development for the prevention of serious lower respiratory tract disease caused by RSV in pediatric patients. GlaxoSmithKline had previously investigated a related PanAd3 vector in a prime-boost schedule with a modified vaccinia virus Ankara (MVA) vector, both of which encoded the same RSV proteins; however, the company has decided to progress with ChAd155-RSV in a standard two-dose schedule.
Analyst Outlook
ChAd155-RSV (GlaxoSmithKline) is a replication-deficient chimpanzee-derived adenovector vaccine which expresses the respiratory syncytial virus (RSV) fusion (F), nucleocapsid (N), and matrix (M2-1) proteins. In preclinical studies and a single first-in-human Phase I study, related adenoviral vectors have displayed promising immunogenicity as measured by the stimulation of antigen-specific T-cell and serum-antibody responses; however, their protective efficacy is yet to be established. Importantly, the adenoviral vector is not neutralized by pre-existing antibodies, potentially allowing the vaccine to be used in neonates and young infants who are at a high risk of developing severe RSV disease, as well as in the seropositive elderly population. This is a key advantage over rival live-attenuated vaccines (LAVs), which, to date, have struggled to demonstrate immunogenicity in very young infants and seropositive individuals due to the pre-existence of neutralizing antibodies.
ChAd155-RSV is a chimpanzee-derived adenovector vaccine encoding the F, N, and M2-1 proteins. The vaccine is in Phase II development for the prevention of serious lower respiratory tract disease caused by RSV in pediatric patients. GlaxoSmithKline had previously investigated a related PanAd3 vector in a prime-boost schedule with a modified vaccinia virus Ankara (MVA) vector, both of which encoded the same RSV proteins; however, the company has decided to progress with ChAd155-RSV in a standard two-dose schedule.
Analyst Outlook
ChAd155-RSV (GlaxoSmithKline) is a replication-deficient chimpanzee-derived adenovector vaccine which expresses the respiratory syncytial virus (RSV) fusion (F), nucleocapsid (N), and matrix (M2-1) proteins. In preclinical studies and a single first-in-human Phase I study, related adenoviral vectors have displayed promising immunogenicity as measured by the stimulation of antigen-specific T-cell and serum-antibody responses; however, their protective efficacy is yet to be established. Importantly, the adenoviral vector is not neutralized by pre-existing antibodies, potentially allowing the vaccine to be used in neonates and young infants who are at a high risk of developing severe RSV disease, as well as in the seropositive elderly population. This is a key advantage over rival live-attenuated vaccines (LAVs), which, to date, have struggled to demonstrate immunogenicity in very young infants and seropositive individuals due to the pre-existence of neutralizing antibodies.
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