RSV is responsible for respiratory infections such as bronchiolitis and viral pneumonia in infants.
It is estimated that in the world, 33 million cases of RSV occur in children who are aged below five years of age, and over 1.4 infants under six months of age get hospitalised.
GSK has designed the vaccine candidate with an aim of preventing medically assessed RSV-associated lower respiratory tract illnesses (LRTIs) in infants during the first six months of life by transfer of maternal antibodies.
The candidate vaccine consists of a recombinant subunit pre-fusion RSV antigen (RSVPreF3), which has demonstrated promising safety and immunogenicity in a phase 1/2 study in non-pregnant women.
According to the company, the data of phase ½ study demonstrated that the vaccine candidate was well-tolerated and able to quickly enhance the pre-existing immunity in non-pregnant women.
The double-blind phase 3 investigational RSV maternal vaccine study, called GRACE (investiGational RSV mAternal vacCinE) has been designed to assess efficacy of a single dose of the RSV maternal unadjuvanted vaccine candidate.
The vaccine candidate will be administered intramuscularly to pregnant women who are in good general maternal health and aged between 18 and 49 years to prevent medically assessed RSV-associated LRTIs in their new-born infants.
As infants are considered to be too young to be immunised in their first months of life, and therefore maternal immunisation is expected to be helpful protecting babies from RSV infections.
The study, which will recruit up to 10,000 pregnant women, will also examine the safety of the candidate vaccine both in vaccinated mothers and in their infants.
GSK intends to complete the trial in early 2024, and expects to reveal the interim results by the second half of 2022.
GSK R&D vaccines head and senior vice president Emmanuel Hanon said: “RSV burden is high amongst young infants – a vaccine which protects them from birth would represent significant progress in addressing the burden of RSV, preventing infant illness and families’ distress, as well as reducing the associated burden for society.
“Advancing our portfolio of RSV vaccine candidates based on robust available data is a major step towards GSK’s goal of reducing the RSV-associated disease burden around the world.”
In October, GSK) and Vir Biotechnology announced their plans to expand the study of a VIR-7831 (GSK4182136) monoclonal antibody to treat Covid-19.