Citi analyst Andrew Baum upgraded Merck (MRK) to Buy and raised his price target for the shares to $72 from $65. The healthcare giant closed yesterday down 12c to $63.22.

While Merck's non-Keytruda business continues to erode, the market is undervaluing both the ultimate patient derived xenograft market size and Merck's likely market share with Keytruda, Baum tells investors in a research note. The analyst revised his initial PDx market estimates of $35bn to at least $50bn and increased his 2025 Keytruda forecasts from $9B to$15B. The analyst prefers Eli Lilly (LLY), Bristol-Myers (BMY) and Merck among the U.S. pharmaceutical majors. He also downgraded Roche (RHHBY) this morning to Neutral.