** Shares of obesity drug developers Structure Therapeutics GPCR.O and Viking Therapeutics VKTX.O fall between 7% and 8% in premarket trading

** GPCR down 7.2% at $29.20 and VKTX down 8.3% at $42.80

** Merck MRK.N signed a deal worth up to $2 bln with Hansoh Pharma 3692.HK to develop and sell the Chinese biotech's experimental oral obesity drug

** "We wonder whether this was the right deal for them, given the highly competitive nature of the space" - Brokerage BMO Capital Markets

** "This asset is preclinical and well behind Lilly's orforglipron, Structure's '1290, and Pfizer's danuglipron" - brokerage

** "Consequentially, we expect GPCR shares to be under pressure today" - BMO Capital Markets

** "From our conversations with clients, Merck represents one of the most likely acquirers of Viking; as a result, Viking shares will understandably sell off today" - Brokerage William Blair

** Companies such as GPCR and VKTX, as well as Novo Nordisk NOVOb.CO and Eli Lilly LLY.N, are developing oral weight-loss treatments in the hopes of providing patients with a convenient dosing option

** Up to last close, GPCR down 22.8% while VKTX up 150.9% YTD

(Reporting by Sneha S K)

((Sneha.SK@thomsonreuters.com;))