Alteogen has secured a European composition patent for Keytruda SC, a subcutaneous version of MSD’s cancer drug developed with the company’s ALT-B4 formulation-conversion technology. The patent runs through 2040 and may be extended by up to five years through a supplementary protection certificate, which compensates for time spent obtaining regulatory approval. ALT-B4 breaks down hyaluronic acid in subcutaneous tissue, enabling intravenous therapies to be converted into injections that can improve convenience and extend the commercial life of existing medicines. MSD launched Keytruda SC in the United States last year, and the product has also been approved in Europe, Canada, South Korea and Japan. Alteogen recently received $25 million as the first payment under an agreement providing for up to $1 billion in sales-based milestones, alongside potential additional milestones and royalties tied to future sales. The company is expanding its patent portfolio globally, following earlier U.S. protection for Keytruda SC, U.S. registration of the ALT-B4 substance patent in July last year, and a European registration decision in June this year.