On September 26, 2023, Caribou Biosciences, Inc. (the ?Company?) received notice from AbbVie Manufacturing Management Unlimited Company (?AbbVie?) that AbbVie has elected to terminate the Collaboration and License Agreement, as amended, by and between the Company and AbbVie, dated February 9, 2021 (the ?Agreement?). AbbVie exercised its right to terminate the Agreement for convenience, and this decision was based on AbbVie?s strategic focus and was unrelated to Caribou?s performance under the Agreement or the data generated to date. By mutual agreement of the Company and AbbVie, termination of the Agreement will be effective October 25, 2023.

Under the terms of the Agreement, the Company was conducting certain preclinical research, development, and manufacturing activities for two AbbVie programs, each program comprising one or more collaboration allogeneic CAR-T products directed toward the single cancer target or target combination, using the Company?s Cas12a chRDNA genome-editing and CAR-T cell therapy technologies. AbbVie has elected not to advance these two programs and, effective upon termination of the Agreement, all licenses granted thereunder will immediately terminate.