** Shares of drug developer Vor Biopharma VOR.O rise 7% to $33.47 premarket

** Brokerage Stifel upgrades stock rating to "buy" from "hold," citing it is positive on telitacicept's prospects across autoimmune diseases

** Stifel sets PT of $55 after the co's stock began trading on a split-adjusted basis; it had a previous PT of 30 cents per share

** Under the reverse stock split announced last week, every 20 shares of Vor were converted into one share

** Brokerage says telitacicept is "poised to potentially emerge as a best-in-class dual BAFF/APRIL antagonist," citing its mechanism and clinical promise

** Telitacicept already has three regulatory approvals in China with two more filings planned

** Stifel now estimates about $5 billion in peak sales from telitacicept

** As of last close, stock up 40% YTD

(Reporting by Kamal Choudhury in Bengaluru)

((Kamal.Choudhury@thomsonreuters.com;))