Y-mAbs Therapeutics Acquisition Finalized by SERB Pharmaceuticals

Y-mAbs Therapeutics US9842411095

Y-mAbs Therapeutics has ceased to exist as an independent publicly traded entity. The biopharmaceutical company’s acquisition by SERB Pharmaceuticals has been completed, providing shareholders with a definitive cash exit from their investment.

The deal, which received unanimous approval from Y-mAbs’ board of directors, was formally closed on September 16, 2025. SERB Pharmaceuticals paid $8.60 in cash for each share of Y-mAbs, valuing the total transaction at $412 million. This per-share price represented a substantial 105% premium over Y-mAbs’ closing stock price on August 4, 2025—the last full trading day before the transaction was announced.

Consequently, Y-mAbs shareholders have received $8.60 for every share they held. The company’s equity will no longer trade independently on any stock exchange, marking the conclusion of its journey as a standalone listed company.

Strategic Rationale for SERB

This acquisition represents a strategic expansion for SERB Pharmaceuticals, significantly bolstering its portfolio in the field of rare oncology treatments. The centerpiece of the deal is Y-mAbs’ commercialized asset, DANYELZA® (naxitamab-gqgk), a therapy approved for the treatment of relapsed or refractory high-risk neuroblastoma. Beyond this key drug, SERB also gains ownership of Y-mAbs’ innovative technology platforms, including a preclinical radioimmunotherapy platform.

Key Acquisition Facts:
* Acquiring Entity: SERB Pharmaceuticals
* Price Per Share: $8.60 (all-cash)
* Total Enterprise Value: $412 million
* Share Price Premium: 105% above the August 4, 2025 close
* Closing Date: September 16, 2025

A New Chapter Begins

Moving forward, Y-mAbs Therapeutics will operate as a fully integrated unit within SERB. The company’s final quarterly report as an independent entity, released in August 2025, now stands as a historical footnote. That report detailed a net loss of $3.2 million on revenue of $19.5 million. The future development and commercialization of the acquired assets and platforms are now under the stewardship of the new owner.