Ultragenyx Pharmaceutical, a biopharmaceutical company focused on the development of novel products for rare and ultra-rare diseases, and Dimension Therapeutics have entered into a definitive merger agreement under which Ultragenyx will acquire all of the outstanding shares of common stock of Dimension for $6.00 per share, or approximately $151 million in cash, based on currently outstanding shares. The transaction is structured as a tender offer and will be funded through Ultragenyx’s existing cash resources.

The definitive agreement between Ultragenyx and Dimension has been approved by the Boards of Directors of both companies, and follows the termination of the merger agreement between Dimension Therapeutics and Regenxbio, previously announced on August 25, 2017. Following discussions with both Ultragenyx and Regenxbio, the Board of Directors of Dimension determined that the Ultragenyx transaction represented a superior proposal. Ultragenyx will pay Regenxbio a termination fee pursuant to the Regenxbio merger agreement, on behalf of Dimension.

The transaction is a compelling opportunity to create value as it combines Dimension’s innovative portfolio of assets and its advanced gene therapy platform with Ultragenyx’s late-stage clinical, regulatory, and commercial expertise in the rare disease space. Ultragenyx plans to maintain a gene therapy research and development unit, and a manufacturing team at Dimension’s facilities in Massachusetts in order to retain the team’s significant gene therapy knowledge and to efficiently progress critical manufacturing development.

Emil D. Kakkis, M.D., Ph.D., Chief Executive Officer and President of Ultragenyx, said, “The acquisition of Dimension provides a unique opportunity to approach treatment of more rare diseases and advance our development as a next-generation rare disease company. Specifically, we look forward to leveraging our development and commercial skills in combination with Dimension’s gene therapy technology, programs and people to accelerate the process of expanding treatment options and bringing important new therapies to market for patients.”

“We are pleased to reach this agreement with Ultragenyx, which provides a substantial premium and immediate, certain value to Dimension stockholders,” said Dimension Chief Executive Officer, Dr. Annalisa Jenkins, M.B.B.S., F.R.C.P. “I am thankful for the hard work and dedication of our talented employees, and am confident they will continue to make valuable contributions as part of a larger organization. I look forward to working closely with Ultragenyx to seamlessly bring our companies together to realize the power of this compelling combination.”

The combined company is expected to bring numerous benefits to all stakeholders, including:

• Compelling, all-cash transaction for Dimension stockholders: The transaction will deliver significant and certain value to Dimension stockholders.
• Provides Ultragenyx with new therapeutic modalities and capabilities: Dimension provides a technology platform allowing Ultragenyx to expand into gene therapy, which is an excellent therapeutic fit in the metabolic genetic disease area and complementary to Ultragenyx’s small molecule, protein and mRNA modes of treatment.
• Diversifies Ultragenyx’s Clinical and Preclinical Pipeline: Dimension’s programs are at an early stage of clinical development and add significant upcoming milestones that are complementary to Ultragenyx’s later stage and filed programs.
• Enables acceleration of Dimension’s programs: Ultragenyx’s integrated rare disease capabilities and global resources will position the combined company to accelerate development and commercialization of Dimension’s assets.

The tender offer is not subject to a financing condition and is expected to close before the end of 2017.