CytomX Platform Improvements IP. CytomX shall solely own all right, title and interest in and to any and all CytomX Platform Improvements IP arising under this Agreement, including any Patent Rights with respect thereto and the right to pursue the same. Regeneron hereby assigns to CytomX all right, title and interest in and to any such CytomX Platform Improvements IP; provided, that if such assignment is prohibited by applicable Law, then Regeneron shall grant, and hereby does grant, to CytomX, a perpetual, irrevocable, exclusive (even as to Regeneron), worldwide, royalty-free, fully paid-up license, with the right to grant sublicenses

through multiple tiers, under such CytomX Platform Improvements IP. Regeneron will cooperate with CytomX to execute any agreements, instruments and documents as may be reasonably required to perfect CytomX’s right, title and interest in and to such CytomX Platform Improvements IP.

Regeneron Background Improvements IP. Regeneron shall solely own all right, title and interest in and to any and all Regeneron Background Improvements IP arising under this Agreement, including any Patent Rights with respect thereto and the right to pursue the same. CytomX hereby assigns to Regeneron all right, title and interest in and to any such Regeneron Background Improvements IP; provided, that if such assignment is prohibited by applicable Law, then CytomX shall grant, and hereby does grant, to Regeneron, a perpetual, irrevocable, exclusive (even as to CytomX), worldwide, royalty-free, fully paid-up license, with the right to grant sublicenses through multiple tiers, under such Regeneron Background Improvement IP. CytomX will cooperate with Regeneron to execute any agreements, instruments and documents as may be reasonably required to perfect Regeneron’s right, title and interest in and to such Regeneron Background Improvements IP.