London-listed Puretech Health PLC (LON:PRTC) hailed the first US approval for a drug it helped to develop.
Gelesis, which is 20.5% owned by Puretech, received the go-ahead for weight reduction aid Plenity earlier than expected and with a much wider marketing label.
Plenity has been cleared for the BMI 25-40 kg/M2 category, the widest category of adults suffering from obesity.
The orally-delivered treatment will now be available alongside diet and exercise to millions of overweight people who previously would not have had a prescribed treatment, said Puretech.
Broker Peel Hunt added the wide label roughly doubles the addressable market it had expected and has raised its target price for Puretech shares to 344p from 320p.
Puretech specialises in microbiome-derived treatments and conceived and developed the platform technology behind Plenity.
Shares rose 7% to 175p.