SERB Pharmaceuticals has agreed to acquire Y-mAbs Therapeutics in an all-cash transaction valued at about $412 million, or $8.60 a share. The price represents a 105% premium to Y-mAbs’ closing level on 4 Aug. 2025 and was unanimously backed by the target’s board. The deal gives SERB control of DANYELZA, the first U.S. Food and Drug Administration-approved therapy for relapsed or refractory high-risk neuroblastoma, and broadens the buyer’s rare-oncology portfolio, which already includes Voraxaze, Vistogard and Xermelo. Roughly 16% of Y-mAbs shareholders have signed agreements to tender their stock. SERB plans to start the tender offer by 19 Aug., with completion expected in the fourth quarter pending customary conditions, including clearance under the Hart-Scott-Rodino Act. Y-mAbs shares will be delisted from Nasdaq once the transaction closes.