Japan approved the manufacturing and marketing of MSD’s Keytruda SC, marketed as Kiject, making it the country’s first approved subcutaneous immune checkpoint inhibitor. The product combines pembrolizumab with Alteogen’s ALT-B4, a recombinant human hyaluronidase that enables high-volume biologic drugs to be administered under the skin. The approval was based on phase 3 trial MK-3475A-D77 in patients with advanced or recurrent non-small cell lung cancer, in which combination therapy delivered subcutaneously was non-inferior to intravenous treatment and raised no new safety concerns. Keytruda SC takes about 1–2 minutes to administer, compared with approximately 30 minutes for the intravenous formulation, and now has the same indications in Japan as Keytruda. Japan is the fourth major market to authorize the product, after the United States, Europe and Canada. MSD reported $590 million in Keytruda SC sales in the first half of 2026, including $463 million in the second quarter, while Alteogen received its first $25 million sales milestone under an agreement providing for up to $1 billion in such payments. Alteogen also receives royalties on net sales.