Drugs such as Ozempic (a brand name for semaglutide) are showing promise for weight loss. Another medication in the same class has impressed in a recent phase 2 clinical trial – and it only needs to be taken once a month.

Amgen's long-acting experimental obesity drug MariTide needs to be given at a low starting dose to limit side effects like vomiting, according to mid-stage trial results presented at a medical meeting on Monday that pushed the company's shares down nearly 6%.

Amgen shares fell sharply on Monday afternoon after the company released results from a weight-loss trial that showed that lots of patients had stopped taking Amgen’s experimental weight loss shot after experiencing gastrointestinal distress.