Interim data from Phase ½ study demonstrates that the two candidate vaccines induced enhanced immune response and are well-tolerated


GSK's head office in Brentford, London. (Credit: Ian Wilson/Wikipedia.)

GlaxoSmithKline (GSK)’s Respiratory Syncytial Virus (RSV) vaccines for immunisation in maternal and older adults were well-tolerated and showed high immune response in Phase ½ clinical studies.

RSV is a virus that causes respiratory tract infections including bronchiolitis and pneumonia in infants and older adults. The virus is estimated to cause hospitalisation of around 3 million children, aged below 5 years globally, and 177,000 older people in the US.

The British drugmaker developed the two vaccine candidates to comprise a recombinant subunit pre-fusion RSV antigen (RSVPreF3) which is through to induce the desired immune response.

Vaccine for older adults additionally features the company’s AS01 adjuvant system to enhance immune response, as they show immune response to vaccination compared to younger adults.

The vaccines are part of the company’s customised portfolio of three RSV candidate vaccines, maternal, paediatric and older adults, which have been granted FDA fast-track designation.

GSK senior vice-president and vaccines R&D head Emmanuel Hanon said: “RSV is an infectious disease that can have a very serious impact on families and societies.

“We are delighted to see these positive results confirming our approach to develop dedicated vaccines building on the strategic use of our platform technologies for the populations most at risk from RSV infections, young infants and older adults.

“Our portfolio strategy takes into account the unique needs of the immune system of these vulnerable populations and we look forward to progressing these assets to Phase III trials to evaluate their potential efficacy.”

RSV vaccines for maternal and older adults showed high immune response

The vaccine candidate for older adults was first tested in 48 healthy adults, aged between 18 and 40 years, and then in 1,005 healthy older adults, aged between 60 and 80 years, with different dosages of antigen and adjuvant versus placebo.

The interim one month data after immunisation showed that the candidate vaccine for older adults resulted in high humoral and cellular immunity when compared to baseline.

Also, the immunisation increased protective RSVPreF3 IgG and RSV-A neutralising antibodies by nearly tenfold, and boosted the cellular immunity similar to that of younger adults, regardless of the initial reduced level.

RSV candidate vaccine for maternal immunisation was evaluated in 502 healthy non-pregnant women over monthly visits at Day 8, Day 31 and Day 91, using 3 different doses, compared with placebo.

The data show that, the potential vaccine was is capable of boosting the pre-existing immunity at all dose levels, enhancing the levels of protective neutralising antibodies, compared with baseline.

The vaccine increased RSV-A and RSV-B neutralising antibodies titers by 14 times, at Day 8, said the company.

GSK intends to begin Phase 3 clinical trials for both older adults and maternal RSV candidate vaccines in months, based on available data and engagement with regulators.