South Korea-based Alteogen unveiled a licensing agreement with GSK subsidiary Tesaro to develop a subcutaneous formulation of programmed death-1 (PD-1) inhibitor Jemperli (dostarlimab) using its proprietary Hybrozyme enzyme technology. Tesaro acquires world-wide non-exclusive rights to use ALT-B4, Alteogen’s novel hyaluronidase, in return for a USD 20 million upfront payment and total development, regulatory, and commercial milestone commitments worth up to USD 285 million. Alteogen will also be granted royalties on future sales.

Jemperli is an anti-PD-1 monoclonal antibody first approved by the US FDA in 2021 as a second-line therapy for mismatch repair deficient (dMMR) recurrent or advanced endometrial cancer. The FDA expanded Jemperli’s indications to include chemotherapy followed by Jemperli in primary advanced or recurrent endometrial cancer, including both dMMR and microsatellite instability-high (MSI-H) tumors.

Alteogen’s ALT-B4 hyaluronidase enzyme enables the conversion of antibodies to subcutaneous formulations by temporarily increasing tissue permeability, facilitating drug absorption. The collaboration addresses a critical challenge in immuno-oncology: improving patient convenience for checkpoint inhibitor administration. By converting dostarlimab from an intravenous to a subcutaneous formulation, the partnership could significantly reduce treatment burden for patients with endometrial and microsatellite instability-high (MSI-H) cancers.

Competitive Context

The subcutaneous delivery approach represents an increasingly popular differentiation strategy for immuno-oncology drug developers. Merck & Co., previously partnered with Alteogen in 2020 for a subcuatenous formulation of Keytruda, branded Keytruda Qlex (pembrolizumab and berahyaluronidase alfa-pmph), securing US FDA approval for all of the drug’s solid tumor indications in September 2025. Other companies with subcutaneous PD-(L1) drugs either under development or on the market include Roche, AstraZeneca, and Bristol-Myers Squibb.