** Brokerage Stifel cuts rating on Neumora Therapeutics NMRA.O to "hold" from "buy" after Johnson & Johnson JNJ.N scrapped trials of a depression drug similar to NMRA's navacaprant

** Stifel among six joint-bookrunners of NMRA's IPO in 2023; at least two others including JP Morgan and RBC have cut ratings on Neumora in recent months

** J&J said on Thursday it will stop late-stage studies of its experimental drug, aticaprant, for major depressive disorder due to a lack of sufficient efficacy

** "We had always seen the success of aticaprant ... as an important source of validation for the KORA mechanism," says Stifel, referring to the class of drugs known as KOR antagonists

** NMRA stock plunged about 80% in early January after its experimental drug navacaprant flunked a late-stage trial in depression patients

** Stifel cuts PT to $2 from $6, a ~31% upside to stock's last close; shares down about 90% since IPO in September 2023

(Reporting by Manas Mishra)

((Manas.Mishra@thomsonreuters.com; www.twitter.com/Manaswrites15;))