Prime Medicine Inc

We currently lease and occupy the following spaces:

•approximately 50,000 square feet of laboratory and office space at 60 First Street, Cambridge, MA 02141 under a lease term that expires in February 2034;

•approximately 27,000 square feet of combined laboratory and office space at 64 Sidney Street, Cambridge, MA 02139 under a lease term that expires in April 2025; and

•approximately 16,000 square feet of combined laboratory and office space at 480 Arsenal Street, Watertown, MA 02472 under a lease term that expires in April 2027.

In addition to these spaces, we have secured approximately 99,000 square feet of additional office and laboratory space at 60 First Street, Cambridge, MA 02141 and 49,000 square feet of new office and laboratory space at 500 Arsenal Street, Watertown, MA 02472. We expect to begin to occupy these spaces in the first half of 2025.

We believe that our facilities are adequate for our current needs and for the foreseeable future and that suitable additional or substitute space at commercially reasonable terms will be available as and when needed.