Eli Lilly has cut the price for vials of its weight-loss drug Zepbound sold online and expanded the range of doses in an attempt to stave off stiff competition from compounding pharmacies and rival Novo Nordisk.

Few big pharma stocks have been bigger winners over the last three years than Eli Lilly and Novo Nordisk. Lilly now ranks as the largest drugmaker in the world, with a market cap of $844 billion, after its shares skyrocketed more than 270%. Novo Nordisk stock is up around 75% despite a pullback in recent months.

The American pharmaceutical company has started selling higher doses of Zepbound, as it seeks to spur demand for the medicine