In November 2017, the Company entered into a lease agreement for its current corporate headquarters comprising approximately 28,731 square feet of office and laboratory space at 26 Landsdowne Street in Cambridge, Massachusetts, commencing December 2017. The Company began to occupy and use the leased space for its intended purpose in June 2018. The lease ends on June 30, 2028. The Company has the option to extend the term of the lease for an additional five-year period, at the market rate, by giving the landlord written notice of its election to exercise the extension at least nine months prior to the original expiration of the lease term. The lease has a total commitment of $25.1 million over the ten year term, and includes escalating rent payments. The lease provides the Company with an allowance for normal leasehold improvements of $5.0 million. The lease agreement requires the Company to either pay a security deposit or maintain a letter of credit of $1.1 million. The Company maintains a letter of credit for this lease and has recorded the cash held to secure the letter of credit as restricted cash on the consolidated balance sheet as of December 31, 2023 and December 31, 2022. Operating lease and variable lease expense associated with this lease for the year ended December 31, 2023 was approximately $1.9 million and $0.9 million, respectively. Operating lease expense and variable lease expense associated with this lease for the year ended December 31, 2022 was approximately $1.9 million and $1.0 million, respectively.

The future minimum lease payments associated with the 26 Landsdowne Street lease as of December 31, 2023, are as follows (in thousands):


2024		2,572
2025		2,649
2026		2,729
2027		2,811
Thereafter		1,426
Total minimum lease payments		12,187
Less: imputed interest		(1,575	)
Total lease liability	$	10,612

In November 2021, the Company entered into a lease agreement comprising approximately 12,196 square feet of office space at 125 Sidney Street in Cambridge, Massachusetts, commencing November 2021. The Company began recognizing rent expense associated with this lease during November 2021. The lease ends on March 31, 2024. The Company has the option to extend the term of the lease for two successive one-year periods, at the market rate, by giving the landlord written notice of its election to exercise the extension at least nine months prior to the original expiration of the lease term. The lease has a total commitment of $1.7 million over the initial term, and includes escalating rent payments. Operating lease expense associated with this lease for each of the years ended December 31, 2023 and 2022 was approximately $0.7 million. No variable lease expense was recorded associated with this lease for the years ended December 31, 2023 and 2022. The future minimum lease payments associated with this lease as of December 31, 2023, are as follows (in thousands):


2024		210
Total minimum lease payments		210
Less: imputed interest		(1	)
Total lease liability	$	209