** Shares of drugmaker Merck MRK.N rise 1.5% to $117.67 premarket

** Partner Sichuan Kelun-Biotech Biopharmaceutical 6990.HK late on Thursday said their experimental cancer treatment combined with Merck's Keytruda met the main goal of a late-stage study

** The combination reduced the risk of lung cancer progression or death by about 65%, the company said

** Merck is developing sac-TMT, an antibody-drug conjugate (ADC), with Chinese biotech firm Kelun-Biotech

** Shares of Summit Theraputics SMMT.O, which is also developing a lung cancer treatment called ivonescimab, fell 4.9% to 416.60

** "SMMT is indicating down post-market on these data being interpreted as a competitive headwind to ivonescimab, which doesn't make much sense to us because ivo is meant to replace pembro (Keytruda) while the role of ADCs versus chemo needs to be sorted separately" - Guggenheim

** Up to last close, MRK up 10.1% and SMMT down 0.11% YTD