** Shares of drugmaker Amgen AMGN.O fall 5.8% to $272.64

** Company says people started on a low dose of its experimental obesity drug, MariTide, achieved weight loss comparable to those on higher doses, while experiencing milder side effects in a mid-stage clinical trial

** Company adds that vomiting was reported in nearly 90% of patients started at the highest tested dose, compared with 50% of patients who ramped up to a full dose in one step and 22% of those brought to their target dose over eight weeks

** In late-stage trials, Novo Nordisk's NOVOb.CO GLP-1 obesity drug Wegovy had a vomiting rate of 24%, while Eli Lilly's LLY.N Zepbound had a rate of 13%

** Amgen says trial discontinuation rates due to gastrointestinal issues of up to 7.8% were lower for groups treated with escalating doses

** Amgen plans to initiate additional late-stage studies this year to test MariTide in patients with various serious health conditions

** Including session moves, stock up 5.2% YTD

(Reporting by Sneha S K)