Lexeo Therapeutics, Inc.

Our corporate headquarters is located at 345 Park Avenue South, 6 th Floor, New York, NY 10010, where we lease a total of approximately 15,839 square feet of office and laboratory space, excluding the additional approximate 11,588 square feet that we began to lease in the first quarter of 2026, used for our research and development activities, general and administrative activities and other activities. This lease agreement began in April 2022 and expires in July 2029 with an additional five-year option to extend at the then-prevailing effective market rental rate. In March 2026, the original lease agreement was amended to include an additional approximate 11,588 square feet of leased office and laboratory space at the same address as the original headquarters lease and to be used for the same purposes. The amended lease agreement began in March 2026 with an initial term of three months, which will automatically renew for an additional three-month period(s) unless either party provides written notice to terminate the agreement.

We believe that our current facilities are sufficient to meet our current and near term needs and that suitable additional or substitute space will be available at commercially reasonable terms as and when needed.