** Shares of Summit Therapeutics SMMT.O settle 36% lower to $23.47 at close, last up 3.81% to $24.36 in after-market trade

** Co says in the submission for cancer drug ivonescimab in China by partner Akeso 9926.HK, the regulators asked for an interim analysis of overall survival

** The drug was approved in China based on a trial that studied it against Merck's MRK.N Keytruda in patients with a type of lung cancer

** The analysis showed a potential 22% reduced risk of death, with a hazard ratio of 0.777, which is not statistically significant, two analysts said

** The simple fact that this still early cut is not statistically significant is triggering a massive sell-off - Evercore ISI

** Summit said the interim analysis was conducted at 39% data maturity

** Brokerage Truist expects overall survival benefit will reach statistical significance by the final analysis, if not potentially earlier

** SMMT shares peaked in September 2024 after results from a study in China showed some lung cancer patients had better survival rates than Keytruda

** Stock up 31.5% YTD

(Reporting by Sriparna Roy in Bengaluru)

((Sriparna.Roy@thomsonreuters.com;))