** Brokerage H.C. Wainwright upgrades cancer therapy developer Lyell Immunopharma's LYEL.O rating to "buy" from "neutral"; raises PT to $45 from $20

** New PT represents a 45.3% upside to the stock's Monday close

** Brokerage says Lyell's Ronde-cel "has established itself as the durability leader" among rival cell therapies for large B-cell lymphoma, an aggressive type of blood cancer

** Ronde-cel is the only therapy to report an 18-month median progression-free survival, a key measure of how long patients live without their disease worsening, H.C. Wainwright notes

** Brokerage also sees big potential in Lyell's LYL273 therapy for colorectal cancer, saying its 25-month survival data more than doubles the benchmark and its 67% response rate far surpasses current standard-of-care options that offer "response rates below 6%"

** Market is "severely underestimating" LYL273's chance to become a standard-of-care option in a multi-billion-dollar segment - brokerage

** Ronde-cel is being tested in two major trials - one comparing it with existing treatments for earlier-stage lymphoma, and another in patients whose cancer has returned after several therapies

(Reporting by Kanishka Ajmera in Bengaluru)

((Kanishka.Ajmera@thomsonreuters.com))