We have formed collaborations with companies such as Bristol-Myers Squibb Company (“BMS”), Betta Pharmaceuticals Co., Ltd. (“Betta”), Gilead Sciences, Inc. (“Gilead”), Incyte Corporation (“Incyte”), Merck Sharpe & Dohme (“Merck”) and Recepta Biopharma SA. Through these alliances, as well as our own internal programs, we currently have more than a dozen antibody programs in pre-clinical or clinical development.
Pursuant to our collaboration agreement with Incyte, we have exclusively licensed to Incyte monospecific antibodies targeting GITR, OX40, TIM-3 and LAG-3, which Incyte is currently advancing in various clinical trials, as well as an additional undisclosed target that Incyte is advancing in preclinical studies. Under the terms of our agreement, Incyte is responsible for all future development expenses, and we are eligible to receive up to an additional $500.0 million in potential milestone payments plus royalties on any future sales. Pursuant to our collaboration and license agreement with Merck, we exclusively licensed to Merck a monospecific antibody targeting ILT4, which Merck is advancing in a Phase 2 clinical trial. Under the terms of our agreement, Merck is responsible for all future development expenses, and we are eligible to receive up to an additional $85.0 million in potential milestone payments plus royalties on any future sales. In September 2018, we, through our wholly-owned subsidiary, Agenus Royalty Fund, LLC, entered into a royalty purchase agreement (the “XOMA Royalty Purchase Agreement”) with XOMA (US) LLC (“XOMA”). Pursuant to the terms of the XOMA Royalty Purchase Agreement, XOMA purchased 33% of all future royalties and 10% of all future milestone payments that we are entitled to receive from Incyte and Merck, net of certain of our obligations to a third party. After taking into account our obligations under the XOMA Royalty Purchase Agreement, as of December 31, 2021, we remain eligible to receive up to $450.0 million and $76.5 million in potential development, regulatory and commercial milestones from Incyte and Merck, respectively.
In December 2018, we entered into a series of agreements with Gilead to collaborate on the development and commercialization of up to five novel I-O therapies (the “Gilead Collaboration Agreements”). Pursuant to the Gilead Collaboration Agreements, Gilead received worldwide exclusive rights to our bispecific antibody, AGEN1423, as well as the exclusive option to exclusively license AGEN1223, a bispecific antibody, and AGEN2373, a monospecific antibody. All three assets have entered clinical development. In November 2020, Gilead elected to return AGEN1423 to us and to voluntarily terminate the license agreement effective as of February 4, 2021. In the third quarter of 2021, we ceased development of AGEN1223 and in October 2021 the AGEN1223 option and license agreement was formally terminated. The AGEN2373 option agreement remains in place, and we are responsible for developing the program up to the option decision point, at which time Gilead may acquire exclusive rights to the program on option exercise. We have the right to opt-in to share Gilead’s development and commercialization costs in the United States in exchange for a profit (loss) share on a 50:50 basis and revised milestone payments. Pursuant to the terms of the AGEN2373 option agreement, we remain eligible to receive up to $10.0 million in aggregate milestone payments prior to option exercise, a $50.0 million option exercise fee and, if exercised, up to an additional $520.0 million in aggregate milestone payments, as well as royalties on any future sales.
In June 2020, we entered into a license and collaboration agreement (the “Betta License Agreement”) with Betta, pursuant to which we granted Betta an exclusive license to develop, manufacture and commercialize balstilimab and zalifrelimab in Greater China. Under the terms of the Betta License Agreement, we received $15.0 million upfront and are eligible to receive up to $100.0 million in milestone payments plus royalties on any future sales in Greater China.
In May 2021, we entered into a License, Development and Commercialization Agreement (“BMS License Agreement”) with BMS to collaborate on the development and commercialization of our pre-clinical proprietary anti-TIGIT bispecific antibody program AGEN1777. Under the BMS License Agreement, we granted BMS an exclusive worldwide license under certain of our intellectual property rights to develop, manufacture and commercialize AGEN1777 and its derivatives in all fields; provided, we retained an option to access the licensed antibodies for use in clinical studies in combination with certain of our other pipeline assets subject to certain