In December 2021, the Company entered into a non-cancellable operating lease agreement, as amended subsequently, or the Harrison Lease, pursuant to which the Company leases 31,668 square feet of office and laboratory space located in Boston, Massachusetts, or the Premises. The Harrison Lease commenced for accounting purposes when the Company gained access to the premises on December 29, 2022 or the Lease Commencement Date. The Harrison Lease has a term of nine years and four months from the lease commencement date. The Company’s obligation for the payment of base rent for the Premises began in May 2023, and is currently $0.2 million per month, increasing up to $0.3 million per month during the term of the Lease. The Company has one option to extend the term of the Harrison Lease, for a period of an additional five years. There was no fixed lease rent expense

associated with the Harrison Lease in 2022. As of September 30, 2023, the Harrison Lease was the only lease for which the Company recorded a lease liability and corresponding right-of-use asset.

The landlord has completed significant leasehold improvements to the leased space, a portion of which the Company paid per the terms of the Harrison Lease. The Company paid $2.0 million for the improvements prior to lease commencement in 2022. During the three months ended September 30, 2023, the Company paid $0.5 million for the improvements and $3.4 million during the nine months ended September 30, 2023 for total payments to the landlord for improvements of $5.4 million. The Company has determined that the landlord is the accounting owner of the improvements. Payments made by the Company for the improvements have been included in the calculation of the right-of-use asset and lease liability.

On January 14, 2022, the Company entered into a First Amendment to the Harrison Lease, which updated the Company's pro-rata share of the building premises. On March 27, 2023, the Company entered into a Second Amendment to the Harrison Lease by which the term of the Harrison Lease was extended by two months until May 2032. The Company recorded a $0.3 million reduction to the lease asset and liability during the period to account for this amendment.

During 2022 and the first quarter of 2023, the Company leased office space in Cambridge, Massachusetts, the terms of which were month-to-month, with a 30-day written notice of cancellation. The Company terminated this lease in January 2023. The Company also leased laboratory space at the University of Massachusetts, Mount Ida Campus in Newton, Massachusetts, with an initial lease term from February 1, 2022 to January 31, 2023, which the Company extended until March 2023. The Company also leased space at Innovation Building, University of Oxford in Oxford, United Kingdom. The Company terminated its lease in Oxford in July 2022. All of these leases had terms of under 12 months and are considered short-term lease costs and are not recognized on the condensed consolidated balance sheets.

The components of lease cost were as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2023		2022		2023		2022
Fixed lease cost	$	937	$	—	$	2,862	$	—
Variable lease cost		272		—		709		—
Short-term lease cost		—		370		188		944
Total lease cost	$	1,209	$	370	$	3,759	$	944

Cash payments for operating leases during the nine months ended September 30, 2023 related to lease payments and landlord-owned improvements made to the office and lab space prior to the Company obtaining occupancy. These payments were recorded in the right-of-use asset at December 31, 2022.

The remaining lease term for the Harrison Lease is 8.7 years, and the discount rate is 8.0%.

Future minimum lease payments under the non-cancelable operating leases consisted of the following as of September 30, 2023:


Year Ending December 31,	(in thousands)
2023 (October - December)	$	736
2024		3,004
2025		3,094
2026		3,187
2027		3,282
Thereafter		15,460
Total future minimum lease payments	$	28,763
Less: imputed interest		(8,330	)
Present value of lease liability	$	20,433

Included in the consolidated balance sheet (in thousands)	September 30, 2023
Lease liability	$	2,982
Lease liability, net of current portion		17,451
Total lease liability	$	20,433