Ahead of GSK are Bristol Myers Squibb and Merck, which have already won FDA approvals for subcutaneous formulations of their respective PD-1 blockers Opdivo and Keytruda.
GSK has fronted $20 million to partner with South Korea’s Alteogen in a bid to develop a subcutaneous version of its cancer drug Jemperli, pursuing a similar strategy as other PD-1 leaders like Merck and Bristol Myers Squibb.
Aside from its upfront commitment, GSK, through its Tesaro subsidiary, is on the hook for up to $265 million in development, regulatory and sales milestones, according to a Tuesday release. Alteogen, meanwhile, brings to the table ALT-B4, a recombinant hyaluronidase enzyme that uses the biotech’s proprietary Hybrozyme technology to enable subcutaneous delivery of therapies originally formulated for intravenous dosing.
Alteogen applies its Hybrozyme technology to the hyaluronidase PH20, resulting in what the biotech claims is “a new human hyaluronidase” with better stability and stronger enzymatic activity. This new enzyme can then more effectively digest hyaluronic acid under the skin, enabling the subcutaneous delivery of certain therapies.
GSK will apply this platform to its PD-1 blocker Jemperli, indicated for endometrial cancer and certain solid tumors. In the first nine months of 2025, Jemperli emerged as the pharma’s top-selling cancer product, with £600 million ($806 million) in earnings worldwide.
Under the terms of Tuesday’s agreement, Alteogen will also be entitled to certain sales-based royalties on subcutaneous Jemperli.
GSK’s agreement with Alteogen puts it in the same league as Merck and Bristol Myers Squibb, which in recent years have been pushing to reformulate their intravenous PD-1 blockers into a more patient-friendly under-the-skin injection.
In September last year, Merck scored a key victory with the FDA’s approval of subcutaneous Keytruda, branded Keytruda Qlex, for 38 different malignancies. The new formulation will help Merck weather the sales decline that will come with Keytruda’s loss of exclusivity in 2028. Keytruda Qlex also uses Alteogen’s Hybrozyme technology.
BMS has likewise secured FDA approval for an under-the-skin formulation of its checkpoint inhibitor Opdivo. The nod, which came in December 2024, applied to all of Opdivo’s indications for renal cell carcinoma, melanoma, non-small cell lung cancer, urothelial carcinoma and many other cancers.
Subcutaneous Opdivo was developed using key technologies from Halozyme and is marketed under the brand name Opdivo Qvantig.
