SERB Pharmaceuticals has agreed to acquire Y-mAbs Therapeutics, including its lead oncology asset Danyelza, in an all-cash transaction valued at around $412m.
The acquisition will enhance SERB’s portfolio in rare diseases and medical emergencies, strengthening its position in the global pharmaceutical market.
Under the merger terms, SERB will initiate an all-cash tender offer to purchase all outstanding shares of Y-mAbs common stock.
Y-mAbs shareholders will receive $8.60 per share, reflecting a 105% premium over its last closing share price on 4 August 2025.
The Y-mAbs Board of Directors unanimously approved the transaction after exploring strategic alternatives to maximise shareholder value.
The process involved discussions with potential buyers for Y-mAbs or its Danyelza and Radiopharmaceuticals businesses.
The parties also evaluated additional capital sources for pipeline development.
The transaction is anticipated to close by the fourth quarter of this year.
SERB CEO Vanessa Wolfeler: “High-risk neuroblastoma is not only a rare and devastating pediatric cancer but also one of the most difficult to treat.
Danyelza is recognised as a critical treatment option for patients and expands the treatment pathways available to providers in an outpatient setting.
“Working together with the team from Y-mAbs, I believe we can continue generating data for this product, expand partnerships to additional oncology centers, and have a positive impact on the lives of more neuroblastoma patients and their families.”
Y-mAbs has developed Danyelza, the first FDA-approved treatment for relapsed or refractory high-risk neuroblastoma, a rare paediatric cancer.
The drug is indicated for patients aged one year and older with specific neuroblastoma conditions, offering outpatient administration options.
The acquisition of Danyelza complements SERB’s existing rare oncology portfolio, which includes Voraxaze, Vistogard, and Xermelo.
With the acquisition, SERB aims to enhance its global presence in rare diseases and emergency medicine, providing improved care standards for patients worldwide.
SERB chairman Jeremie Urbain said: “Danyelza is an excellent strategic fit for SERB as it strengthens our existing rare oncology portfolio and will allow us to leverage our existing global footprint and our medical, regulatory, and commercial expertise to expand the reach of Danyelza to new markets.”
Danyelza, in combination with GM-CSF, is indicated for specific neuroblastoma patients, with approval contingent on confirmatory trials.
Rothschild & Co. served as financial advisor, and Freshfields US as legal counsel to SERB, while Centerview Partners served as advisor, and Cooley as legal counsel to Y-mAbs, on this transaction.
H/Advisors Abernathy served as strategic communications advisors for SERB and Joele Frank, Wilkinson Brimmer Katcher for Y-mAbs.
Y-mAbs president, CEO and board of directors’ member Michael Rossi said: “Our Board regularly reviews our business, including our strategy, the current state of the biopharmaceutical sector and the time and resources required to execute on our strategic plans.
“Following the thorough process to explore all of the potential paths forward for the Company, we are now moving forward with this agreement with SERB that we believe reflects the most attractive option available to Y-mAbs, providing significant, immediate and certain value to our stockholders.”
