On July 11, 2023, Omega Therapeutics, Inc. (Company) entered into a shared space arrangement with Apriori Bio, Inc. (Apriori), and on July 12, 2023, the company entered into two Shared Space Arrangements (the three Shared Space Arrangements, collectively, the “Subleases”) with Metaphore Biotechnologies, Inc. (Metaphore) and Flagship Labs 89, Inc. (Labs and, together with Metaphore and Apriori, the Subtenants), pursuant to which the Company agreed to sublease an aggregate of approximately 22,500 rentable square feet of office and laboratory space located at 140 First Street, Cambridge, Massachusetts, 02141 (Premises). The Company leases an aggregate of approximately 89,246 rentable square feet of office and laboratory space located at the Premises pursuant to its lease (Lease) with ARE-MA Region No. 94, LLC (Landlord).

Metaphore, Apriori and Labs are affiliates of Flagship Pioneering, a significant stockholder of the Company. The term of the Sublease with Metaphore and Labs will begin on August 1, 2023 and end on August 31, 2025, and the term of the Sublease with Apriori will begin on September 1, 2023 and end on September 30, 2025. The Subleases provide that the Subtenants will pay to the Company a monthly license fee that is a proportionate share of the actual base rent, operating expenses and other costs for the use and occupancy of the subleased portion of the Premises charged by the Landlord under the Lease and paid by the Company.

Such proportionate share will be 12.0%, 8.4% and 8.4% for Metaphore, Apriori and Labs, respectively. The Company may terminate each Sublease and require the applicable Subtenant to immediately vacate the Premises if such Subtenant causes a default under the Lease, is in default of any provision in the applicable Sublease or acts in a manner deemed by the Company, in its sole discretion, as dangerous or threatening.