Xencor Inc. announced the issuance of U.S. Patent 12,492,253, covering its Xtend™ Fc domain technology for extending the half-life of antibodies targeting C5. The new patent extends the term for this technology into December 2028, approximately three years beyond the previous latest-to-expire U.S. patent for the Xtend Fc domain. This extension also prolongs the U.S. royalty term for Ultomiris® by about three years, with Xencor expecting to receive low-single digit royalties on net sales of Ultomiris through December 2028. The company estimates potential royalty revenue in excess of $100 million to $120 million in aggregate for the extended patent term.