On December 31, 2018, Dicerna Pharmaceuticals, Inc. (the “Company”) and Boehringer Ingelheim International GmbH, a wholly-owned subsidiary of C.H. Boehringer Sohn AG & Co. KG (“BI”) entered into an Additional Target Agreement (the “ATA”). In October 2018, BI exercised its option under a Collaborative Research and License Agreement between the Company and BI, dated October 27, 2017 (the “Original Agreement”) to add the development of product candidates targeting an additional gene (the “Additional Target”) to the development activities governed by the Original Agreement. The ATA provides a research work plan for the Additional Target. The ATA also amends the Original Agreement to provide BI with the option to add the development of product candidates targeting a further additional gene to the Original Agreement (the “Second Option”) for a three-year period, and to provide for the delivery of a replacement product candidate by the Company to BI in the event that a product candidate under the Original Agreement or the ATA fails at certain stages of pre-clinical or clinical development. Under the terms of the ATA, in accordance with the terms of the Original Agreement, BI will pay the Company a non-refundable upfront payment (the “Option Payment”) of $5.0 million to exercise its initial option for development related to the Additional Target. Under the terms of the ATA, during the term of the research program, BI will reimburse the Company for certain expenses. The Company is eligible to receive up to $170.0 million in potential development and commercial milestones related to the Additional Target. The Company is also eligible to receive tiered royalty payments on potential global net sales, subject to certain adjustments, in the mid-single digits. Other than as set in the ATA, development of the Additional Target will be subject to the terms of the Original Agreement.