Ozempic maker Novo Nordisk said on Tuesday it is suing arch US rival Eli Lilly over “false and materially misleading” adverts for its competing weight-loss and anti-diabetes treatments.

The Danish pharmaceuticals heavyweight complained that the US group – which makes rival weight-loss treatments Zepbound and Mounjaro – “intentionally selected outdated studies” that compared Lilly’s highest doses against lower doses of Novo Nordisk’s medicines.