AstraZeneca has made an offer of about $10 billion to acquire Rhythm Pharmaceuticals, the US maker of a treatment for rare forms of obesity, according to Reuters, which cited three people familiar with the matter. The proposal is non-binding and would be worth as much as $134 a share once milestone payments are included.

The Wall Street Journal had earlier reported that AstraZeneca made a $124-a-share offer for the company last month. News of the approach sent Rhythm's shares up 28% to $110.68 on Wednesday 4 November, giving the company a market value of about $7.64 billion. The gap between the market price and the reported offer leaves room for a rival bidder or a revised deal.

The acquisition would be pursued through Alexion, AstraZeneca's rare-disease business, which it bought for $39 billion in 2021 to expand beyond its core oncology and biopharmaceutical franchises. Rhythm develops therapies for rare neuroendocrine disorders, including IMCIVREE (setmelanotide), a treatment for severe obesity driven by the body's melanocortin-4 receptor pathway. Rhythm reported $92.1 million in third-quarter product revenue, up 80% on a year earlier, after US regulators approved IMCIVREE in March 2026 for acquired hypothalamic obesity.

Neither company has confirmed a transaction, and the reports do not establish a signed agreement, a final price or the conditions governing the milestone payments. Rhythm has also secured up to $750 million in term-loan capacity led by KKR's HealthCare Royalty, with Blackstone, as it continues to fund its pipeline while talks continue, according to AInvest. Any deal would still face possible competing bids and regulatory review.