The Company leases approximately 230,000 square feet of real estate, including laboratory and office space in Cambridge, Massachusetts, and the surrounding areas. The Company’s leases have remaining terms ranging from one to approximately nine years. Certain leases include options to renew, exercised at the Company’s sole discretion, with varying renewal terms that can extend the lease term for an additional three to five years. All of the Company’s leases qualify as operating leases.

In January 2023, the Company executed a sublease for approximately 13,000 square feet of space of laboratory and office space in Cambridge, Massachusetts for a term of approximately three years. The sublease agreement grants an option to renew the term for one additional year.

In February 2022, the Company entered into an agreement to lease approximately 140,000 square feet of office, general laboratory and planned good manufacturing practice (“GMP”) manufacturing space at 840 Winter Street in Waltham, Massachusetts (the “840 Winter Lease”). The Company has committed to making at least $146.0 million in rental payments over a lease term of 144 months estimated to begin in the second half of 2024. The Company has the option to extend the 840 Winter Lease for two five-year terms.

In June 2023, the Company executed an amendment to the 840 Winter Lease, which outlines the Company’s and the landlord’s responsibilities regarding the construction of the leased space. The Company will be responsible for the oversight of the construction of the tenant improvements, which will be primarily funded by a tenant improvement allowance of up to $400 per rentable square foot, a portion of which would be repaid over the term of the lease with interest. The Company will also be responsible for certain future construction costs to the extent that they exceed the tenant improvement allowance. The Company anticipates a phased move-in process during the second half of 2024. As of December 31, 2023, the Company had not taken control of the premises and therefore there are no right of use assets or liabilities recorded related to the 840 Winter Lease under ASC 842, Leases (Topic 842) (“ASC 842”).

Throughout the term of its leases, the Company is responsible for paying certain costs and expenses, in addition to the rent, as specified in the lease, including a proportionate share of applicable taxes, operating expenses and utilities. The variable portion of these costs are expensed as incurred and are disclosed as variable lease costs.

The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases:


	Year Ended December 31,
	2023			2022
	(In thousands)
Lease cost
Operating lease cost	$	27,849		$	18,031
Variable lease cost		6,991			4,443
Sublease income		(1,439	)		-
Net lease cost	$	33,401		$	22,474

	Year Ended December 31,
	2023			2022
	(In thousands)
Other information
Operating cash flows used for operating leases	$	25,456		$	14,656
Operating lease liabilities arising from obtaining right-of-use assets		1,311			67,053

	As Of December 31,
	2023			2022
Lease term and discount rate
Weighted average remaining lease term	6.2 years			6.9 years
Weighted average discount rate	7.37%			7.20%

The table below reconciles the undiscounted cash flows for each of the next five years and total of the remaining years to the operating lease liabilities recorded in the consolidated balance sheet as of December 31, 2023:


Future Operating Lease Payments
Year Ending December 31,	(in thousands)
2024	$	26,395
2025		25,933
2026		25,110
2027		17,548
2028		12,300
Thereafter		39,260
Total lease payments	$	146,546
Less: imputed interest		(31,200	)
Total operating lease liabilities at December 31, 2023	$	115,346