Recombinant hyaluronidase (Alteogen)

To sweeten the deal, GSK and Tesaro are offering up to $265 million more tied to certain development, regulatory and sales milestones. With star checkpoint inhibitors like Keytruda and Opdivo now sporting subcutaneous formulations, GSK has struck a deal aimed at ensuring its own PD-1 stalwart doesn’t miss out on the action.GSK, through its oncology subsidiary Tesaro, is handing over $20 million upfront to Alteogen for global rights to the Korean biotech’s novel hyaluronidase enzyme ALT-B4. Tesaro plans to use the tech to develop and potentially market a subcutaneous form of Jemperli (dostarlimab).To sweeten the deal, GSK and Tesaro are offering up to $265 million more tied to certain development, regulatory and sales milestones, Alteogen said in a Jan. 20 press release. Alteogen will also be in line to earn royalties on sales of subcutaneous Jemperli, should it win approval and go to market.The South Korean drugmaker will provide both clinical and commercial supply of its hyaluronidase ALT-B4 to Tesaro, Alteogen added.Alteogen developed ALT-B4 using its bespoke Hybrozyme technology, which the company notes has been designed to boost the flexibility and stability of protein structures while preserving the enzyme's original mechanism of action.By wedding this technology to a type of human hyaluronidase known as PH20, Alteogen says it has developed a new human hyaluronidase that can break down hyaluronic acid in subcutaneous tissue, enabling a shift from intravenous to subcutaneous drug administration."We are excited to expand our Hybrozyme technology by collaborating with Tesaro in the oncology field and look forward to developing and bringing this potential subcutaneous medicine to market," Alteogen’s CEO, Tae-Yon Chun, Ph.D., said in a statement. First approved in 2021 to treat patients with advanced or recurrent mismatch repair-deficient endometrial cancer, Jemperli has significantly expanded in its inaugural indication and also picked up a nod to treat mismatch repair-deficient solid tumors.The drug generated around $598 million in full-year 2024 sales and had lassoed 600 million pounds sterling (then worth around $792 million) as of the first nine months of last year, putting Jemperli squarely in the running to break through the blockbuster sales threshold in 2025. GSK is due to report its 2025 fourth-quarter results on Feb. 4. Jemperli was a latecomer to the PD-1 party, and it follows in the footsteps of Keytruda and other checkpoint inhibitor giants once more as GSK and Tesaro embark on their subQ development journey.In September, Merck & Co. secured an FDA green light for its own under-the-skin version of megablockbuster Keytruda, which will be sold in the subcutaneous format under the brand name Keytruda Qlex. The FDA approval covers all the solid tumor indications included under the intravenous Keytruda label.Prior to that nod, the FDA also approved subcutaneous versions of immunotherapy juggernauts Tecentriq, from Roche, and Bristol Myers Squibb’s Opdivo.Meanwhile, AstraZeneca last year struck a similar deal with Alteogen to use the biotech’s ALT-B4 hyaluronidase to develop subcutaneous versions of “several oncology assets.” While AZ did not disclose financial details or provide further information on the assets it hopes to develop through the deal, an Alteogen filing on the Korea Exchange revealed that it had struck two separate agreements with AZ, potentially totaling $1.35 billion. 

DAEJEON, South Korea, Jan. 20, 2026 /PRNewswire/ -- Alteogen Inc. (KOSDAQ: 196170) announced today that the company has entered into an exclusive license agreement with Tesaro, Inc., a subsidiary of GSK. Under the terms of the agreement, Tesaro will acquire world-wide rights to use ALT-B4, Alteogen's novel hyaluronidase utilizing Hybrozyme™ technology, for the development and commercialization of a subcutaneous formulation of dostarlimab, a programmed death receptor-1 (PD-1) blocking antibody. Alteogen will receive an upfront payment of US$20 million and is eligible to receive milestone payments up to US$265 million upon achievement of specified development, regulatory and sales milestones. Additionally, Alteogen will be entitled to receive royalties on the sales of the commercialized product. Alteogen will be responsible for clinical and commercial supply of ALT-B4 to Tesaro. "We are excited to expand our Hybrozyme™ technology by collaborating with Tesaro in the oncology field, and look forward to developing and bringing this potential subcutaneous medicine to market," said Tae-Yon Chun, Ph.D., CEO of Alteogen. ALT-B4 ALT-B4 is Alteogen's proprietary human recombinant hyaluronidase enzyme developed utilizing Hybrozyme™ technology. ALT-B4 can enable the large volume subcutaneous administration of drugs that are typically administered as an IV infusion. ALT-B4 does this by temporarily hydrolyzing hyaluronan in the extracellular matrix. About Alteogen Inc. Alteogen Inc. is a South Korea-based biopharmaceutical company that focuses on the development and commercialization of novel biologics such as Antibody-Drug Conjugates (ADCs), biobetters, and biosimilars. Alteogen's portfolio includes clinical-stage long-acting therapeutic proteins and next-generation ADCs, developed by its proprietary NexP™-fusion and NexMab™ platform technology, respectively. It also developed a proprietary recombinant human hyaluronidase enzyme utilizing Hybrozyme™ technology, which enables the large volume subcutaneous administration of drugs that are typically administered as an IV infusion. The company was founded in 2008 and listed on KOSDAQ (196170.KQ). Contact Vivek Shenoy, Ph.D., MBA Chief Business Officer Phone: +1 805 570 8998 E-mail: [email protected] SOURCE Alteogen Inc. 21% more press release views with Request a Demo