Lundbeck A/S has expressed interest in acquiring Xeris Biopharma Holdings Inc., a commercial-stage drugmaker, according to people familiar with the matter. The Danish pharmaceuticals company has been working with advisers to explore a takeover of Chicago-based Xeris. Shares in Xeris have risen more than 20% in New York trading over the last 12 months, giving the company a market value of about $1.8 billion. Lundbeck has a market capitalization of roughly 43.3 billion Danish kroner ($6.6 billion).

There’s no guarantee Lundbeck’s interest will result in a deal, the people said. A representative for Lundbeck didn’t provide comment. A spokeswoman for Xeris said the company is “not for sale” and is “laser focused on improving patient lives by developing and commercializing” its medicines. Xeris focuses on treatments for endocrine and rare diseases and has three approved drugs on the market including Recorlev.

Xeris generated $92 million of revenue in the three months that ended in June but surprised analysts with a net loss in the quarter. Lundbeck specializes in treatments for neurological and psychiatric disorders. Mid-cap pharmaceuticals companies like Lundbeck have become more acquisitive in recent years as they’ve sought to boost revenue by adding to their pipelines of medicines.