SERB to acquire Y-mAbs Therapeutics for $8.60 per share in cash

SERB Pharmaceuticals and Y-mAbs Therapeutics (YMAB) entered into a definitive merger agreement under which SERB will acquire Y-mAbs, including its lead commercial oncology asset, DANYELZA, in an all-cash transaction, representing an equity value for Y-mAbs of approximately $412 million. Under the terms of the merger agreement, SERB will commence an all-cash tender offer to purchase all outstanding shares of Y-mAbs common stock. Holders of Y-mAbs common stock would receive $8.60 per share in cash, representing a premium of approximately 105% to Y-mAbs’ closing share price on August 4, 2025, the last full trading day prior to the transaction announcement. The transaction was unanimously approved by the Y-mAbs Board of Directors following a review of strategic alternatives to maximize value for Y-mAbs stockholders, with the assistance of external advisors. The process included discussions with numerous potential buyers for Y-mAbs or for the DANYELZA or Radiopharmaceuticals businesses on a standalone basis. In addition, the Board reviewed potential sources of additional capital to support accelerating the further development of the Company’s pipeline. With a focus on pediatric oncology, Y-mAbs successfully developed and commercialized the anti-GD2 therapy, DANYELZA. DANYELZA is the first FDA-approved treatment for relapsed or refractory high-risk neuroblastoma – a rare and aggressive pediatric cancer – and was approved in the United States under accelerated approval based on overall response rate and duration of response. DANYELZA is indicated for the treatment of pediatric patients one year of age and older and adult patients with relapsed or refractory high-risk neuroblastoma in the bone or bone marrow who have demonstrated a partial response, minor response, or stable disease to prior therapy. In addition to inpatient use, doctors can choose to administer DANYELZA in an outpatient setting, which may reduce the logistical burden on patients and their families. Y-mAbs’ portfolio also includes an investigational therapy targeting GD2 in solid tumors and CD38 in circulating tumors in ongoing Phase 1 clinical trial from its Self-Assembly DisAssembly Pretargeted Radioimmunotherapy Platform. Under the terms of the merger agreement, SERB is obligated to commence a tender offer by August 19, 2025, to purchase all of Y-mAbs’ outstanding shares for $8.60 per share in cash. Assuming a majority of the outstanding Y-mAbs shares are tendered into, and not withdrawn from, the tender offer, and subject to the satisfaction of other customary conditions, including the receipt of a majority of Y-mAbs shares in the tender offer and expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act, SERB is required to close the tender offer, following which, Y-mAbs will be merged with a subsidiary of SERB. After such merger, Y-mAbs shares that were not tendered in the tender offer will be converted into the right to receive the same $8.60 per share in cash paid for shares in the tender offer, and Y-mAbs’ stock will no longer be listed on the Nasdaq exchange. Y-mAbs stockholders holding approximately 16% of Y-mAbs’ outstanding shares of common stock have entered into a tender and support agreement with SERB, pursuant to which such stockholders have agreed, among other things, to tender all of their shares of Y-mAbs common stock in the tender offer, subject to the terms and conditions of such agreement. The transaction is expected to close by the fourth quarter of 2025.