Britain's GSK said on Monday it had halted enrolment and vaccination in three trials of its experimental vaccine against the respiratory syncytial virus (RSV) in pregnant women, the latest setback in developing a vaccine for the microbe.
GSK said on Feb. 18 that it had paused a late-stage trial, dubbed "GRACE," as well as two other studies, based on safety recommendations from an independent committee but did not give further details on what had prompted the recommendations.
RSV is a leading cause of pneumonia in toddlers and the elderly, but vaccine development has been plagued by setbacks for decades. However, many drugmakers are now working to bring a candidate to the market over the next few years.
GSK, the world's biggest vaccine maker by sales, reiterated on Monday that the halts did not affect another trial of its RSV vaccine candidate for adults aged 60 and over, adding that analysis of the safety data from the maternal trials is ongoing.
RSV vaccines are seen as an opportunity for GSK to deliver on pledges to boost its drug development success rate, where it has long lagged industry peers. GSK's shot for pregnant women was aimed at conferring immunity to protect unborn children.
Its vaccine for the elderly, another major vulnerable population, has been regarded by analysts as a potential big RSV market, with trial results expected in the first half this year.