We lease two facilities for office and laboratory space in Cambridge, Massachusetts that represent substantially all of our significant lease obligations. An overview of these significant leases is as follows:

We lease office and laboratory space located at 675 West Kendall Street, Cambridge, Massachusetts for our corporate headquarters from BMR-675 West Kendall Street, LLC under a non-cancelable real property lease. The lease commenced on May 1, 2018 and monthly rent payments became due commencing on February 1, 2019 upon substantial completion of the building improvements, and continue for 15 years, with options to renew for two five-year terms each. We are not reasonably

certain to exercise these options, therefore, the periods covered by the options were not included in the lease term as of December 31, 2025 or 2024.

We lease office and laboratory space located at 300 Third Street, Cambridge, Massachusetts under a non-cancelable real property lease agreement by and between us and ARE-MA Region No. 28, LLC, or ARE-MA, dated as of September 26, 2003, as amended. The term of the lease expires on January 31, 2034 with options to renew for two five-year terms each. We are not reasonably certain to exercise these options, therefore, the periods covered by the options were not included in the lease term as of December 31, 2025 or 2024.

Our facility leases described above generally contain customary provisions allowing the landlords to terminate the leases if we fail to remedy a breach of any of our obligations under any such lease within specified time periods, or upon our bankruptcy or insolvency.

The following table is a summary of the components of total lease cost for the years ended December 31, 2025, 2024, and 2023:


	Years Ended December 31,
(In thousands)	2025		2024		2023
Operating lease cost	$	49,816	$	45,986	$	46,367
Variable lease cost	24,551		19,757		20,278
Total	$	74,367	$	65,743	$	66,645

Our variable lease cost for the years ended December 31, 2025, 2024 and 2023 primarily related to operating expenses, taxes and insurance associated with our real estate leases. Short-term lease costs were not material for the years ended December 31, 2025, 2024 and 2023.

Net cash paid for the amounts included in the measurement of the operating lease liabilities in our consolidated balance sheets and presented within operating activities in our consolidated statements of cash flows was $50.7 million, $51.0 million and $46.5 million for the years ended December 31, 2025, 2024 and 2023, respectively. The weighted-average remaining lease term and weighted-average discount rate for all leases as of December 31, 2025 was 8 years and 8%, respectively, and as of December 31, 2024 was 8 years and 8%, respectively.

Future lease payments for non-cancellable operating leases and a reconciliation to the carrying amount of the operating lease liabilities presented in the consolidated balance sheet as of December 31, 2025 were as follows, in thousands:


Years Ending December 31
2026	$	48,073
2027	52,747
2028	44,308
2029	42,990
2030	41,783
2031 and thereafter	136,375
Total undiscounted lease liability	366,276
Less imputed interest	(95,671)
Total discounted lease liability	$	270,605

Operating lease liabilities	$	45,518
Operating lease liabilities, net of current portion	225,087
Total	$	270,605