GSK announced on January 20 that its portfolio company, Tesaro, will acquire Alteogen’s novel hyaluronidase enzyme ALT-B4 for $20 million.
Alteogen developed ALT-B4 using its bespoke Hybrozyme technology, which the company notes was designed to boost the flexibility and stability of protein structures while preserving the enzyme’s original mechanism of action.
Tesaro is a biopharmaceutical company whose major marketed product, Zejula (niraparib), an oral poly ADP ribose polymerase (PARP) inhibitor, is currently approved for use in ovarian cancer. It is owned by GSK.
The original press release notes that Tesaro plans to use the tech to develop and potentially market a subcutaneous form of Jemperli (dostarlimab). Alteogen also added that Tesaro will provide both clinical and commercial supply of its hyaluronidase ALT-B4 to Tesaro.
According to data captured in the LevinPro HC database, this represents the 10th Biotechnology transaction of the year. There were 135 Biotechnology acquisitions recorded in 2025, with GSK announcing three acquisitions.
Additionally, this is GSK’s second transaction of the year. On the same day, in a separate press release and transaction, GSK acquired Rapt Therapeutics, a clinical-stage immunology-based biopharmaceutical company, for $2.2 billion.
