Glaxo Stops RSV Tests in Pregnant Women on Safety Concern (1)

GlaxoSmithKline Plc, the U.K. drugmaker, stopped trials for a vaccine against the respiratory virus RSV in pregnant women due to potential risks days after announcing a pause.

The decision announced Monday signals a more permanent setback for Glaxo as the pharma giant targets a virus that can be especially serious for infants and older adults and pursues a potential multibillion-dollar market opportunity. The stock fell as much as 1.7% in London trading.

The drugmaker said in a statement that it’s analyzing safety data and has informed regulatory authorities. A spokesman cited the proportion of pre-term births in the group ...