Prime Medicine Inc

We currently lease and occupy the following spaces:

•approximately 10,000 square feet of laboratory and office space at 21 Erie Street, Cambridge, MA 02139 for which we provided notice to terminate and such termination will become effective in June 2024;

•approximately 13,000 square feet of office space at 38 Sidney Street, Cambridge, MA 02139 under a lease term that expires in December 2024;

•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 148,941 square feet in new office and laboratory space at 60 First Street, Cambridge, MA 02141 that we expect to begin to occupy in mid-2024.

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.