AstraZeneca offered $10 billion for Rhythm, sources say

AstraZeneca made an approximately $10 billion offer to acquire US biotech company Rhythm Pharmaceuticals, according to people familiar with the matter. The approach follows earlier interest in Rhythm that AstraZeneca renewed in recent months, The Wall Street Journal said.

The Journal said AstraZeneca offered $124 a share in October 2026, as The Guardian wrote. Separately, Reuters cited people familiar with the matter as saying the non-binding proposal offered as much as $134 a share, including payments tied to milestones.

Rare-disease treatments

Rhythm develops therapies for rare neuroendocrine disorders, which involve the systems that produce and regulate hormones. Acquiring the company would expand AstraZeneca’s rare-disease treatment portfolio, the Journal said.

In March 2026, the US Food and Drug Administration expanded approval of Rhythm’s Imcivree for a rare form of obesity caused by brain damage. It was the first treatment approved in the US for that condition.

Shares rise after offer reported

Rhythm shares closed up 28% at $110.68 on 4 November after the offer was reported. They were about 3% lower in November 5 pre-market trading, a preliminary indication rather than a closing price.

AstraZeneca declined to comment, and Rhythm representatives did not respond to Reuters’ request for comment. Whether negotiations are continuing, or when either company might make a decision, remains unclear.