To the extent that Existing Materials are incorporated in the Work Product, subject to full and final payment by Customer of all sums due to IGX, IGX hereby grants to Customer a royalty-free, irrevocable, worldwide, nontransferable, non-exclusive, internal use, perpetual license to use, modify and prepare derivative works of such Existing Materials and to use and display such Existing Materials, but only to the extent required to utilize the Work Product in accordance with this Agreement. .