On August 22, 2023, CytomX Therapeutics, Inc. entered into a Transition Agreement with AbbVie Global Enterprises Ltd. pursuant to which the Company regained exclusive worldwide rights to develop CX-2029, a CD71-targeting conditionally activated antibody drug conjugate. The Transition Agreement supersedes the recently terminated CD71 Co-Development and License Agreement entered into between the Company and AbbVie Ireland Unlimited Company in 2016 and grants certain intellectual property rights from AbbVie to enable the continued development of CX-2029 by Company for all human and nonhuman diagnostic, prophylactic, and therapeutic uses. Pursuant to the Transition Agreement, AbbVie is eligible to receive tiered sales royalties for CX-2029 ranging from the low-to-mid single digit percentages.

CytomX will also pay Seattle Genetics, Inc. potential future development, regulatory, and commercial milestones, and tiered sales royalties ranging from the mid-to-high single digits percentages related to certain CX-2029 linker payload technology licensed from Seagen. The Company's royalty obligations for a particular CX-2029 product sold in any country shall continue until the later of (i) the date on which such CX-2029 product is no longer covered by certain patent rights in such country, (ii) the loss of regulatory exclusivity for such CX-2029 products in such country, or (iii) the tenth anniversary of the first commercial sale for such CX-20 29 product in such country. The Transition Agreement will continue in effect on a country-by-country basis until the expiration of the obligation to make payments under the Transition Agreement with respect to CX-2029 in each country, unless earlier terminated by either party pursuant to its terms. Either the Company or AbbVie may terminate the Transition Agreement for the other party's insolvency or certain uncured breaches; the Company may terminate the Transition Agreement without cause; and AbbVie may terminate The Transition Agreement if the Company or any of its sublicensees or affiliates challenge certain Seagen patents.

The foregoing summary of the material terms and conditions of the Transition Agreement is qualified in its entirety by the full agreement, a copy of which will be filed as an exhibit to the Company's Quarterly Report on Form 10-Q. The Company intends to omit certain confidential portions of the Transition Agreement.