The Company currently leases approximately 30,000 square feet of office and laboratory space in Cambridge, Massachusetts (the “Cambridge Lease”). The Cambridge Lease was originally set to expire on June 30, 2027.

On December 22, 2025, the Company entered into an amendment to the Cambridge Lease, which provided for rent abatements and refunds and accelerated the termination of the lease to the date thirty days after the commencement of the Watertown Lease (as defined below). The amendment did not result in the Company relinquishing control of the leased premises until the revised termination date.

Concurrently, on December 22, 2025, the Company entered into a lease agreement for approximately 44,000 square feet of laboratory and office space in Watertown, Massachusetts (the “Watertown Lease”) with an affiliate of the Cambridge lessor. The Watertown Lease will commence upon delivery of the premises and availability for use (the “Watertown Lease Commencement Date”), which is contractually targeted to occur approximately 180 days following execution. The initial lease term extends through June 30, 2030.

The Cambridge Lease amendment and the Watertown Lease were negotiated contemporaneously as part of a coordinated relocation transaction with affiliated lessors. Accordingly, the Company combined the arrangements for

accounting purposes under ASC 842 and determined that the combined contract contains two separate lease components: (i) the modified Cambridge Lease and (ii) the Watertown Lease. The total consideration of the combined contract, including contractual Watertown rent, the lease modification fee (as described below) and rent refunds, was allocated to each lease component based on relative standalone prices at the effective date of the modification.

As a result of the modification, the Company remeasured the Cambridge Lease right-of-use asset and lease liability to zero and $1.1 million, respectively, and recorded a gain of approximately $0.3 million during the year ended December 31, 2025, reflecting the net impact of the remeasurement based on the allocated consideration. The gain was included within general and administrative expense and research and development expense in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2025 as $0.1 million and $0.2 million, respectively.

In connection with the relocation transaction, the Company agreed to pay a lease modification fee of approximately $2.1 million, payable in installments commencing after the Company relinquishes control of the Cambridge premises. The portion of the modification fee allocated to the Cambridge Lease was included in the remeasurement described above, and the remainder was allocated to the Watertown Lease component.

As of March 31, 2026, the Watertown Lease had not commenced and, accordingly, no right-of-use asset or lease liability had been recognized for that lease component. The Watertown Lease includes an initial rent-free period of approximately 18 months. It also provides for the use of certain lessor-owned laboratory equipment during the lease term which will be accounted for as a lease incentive related to the Watertown Lease and will reduce the right-of-use asset upon lease commencement.

The Watertown Lease includes an option to extend the lease term for an additional five-year period at market rates. The Company will determine the appropriate incremental borrowing rate and recognize the related right-of-use asset and lease liability upon commencement.

The Company currently leases approximately 5,300 square feet of office and lab space in Boulder, Colorado (the “Boulder Lease”). The Boulder Lease is a five-year lease that commenced on September 1, 2023 and expires on September 30, 2028. As the rate implicit for the Boulder Lease was not readily determinable, the Company used its incremental borrowing rate of 7.12% as of the commencement date. At commencement of the Boulder Lease, the Company recorded $1.4 million of operating ROU assets, $0.2 million of current operating lease liabilities and $1.2 million of non-current operating lease liabilities.

During the year ended December 31, 2025, the Company vacated its Boulder, Colorado facility. The Company is currently pursuing sublease opportunities for the space. During the year ended December 31, 2025, it was determined that the market rate for similar space is less than the rate the Company is paying under the Boulder Lease. As a result, the Company recognized in the consolidated statement of operations an impairment charge of $0.5 million related to the right of use (“ROU”) asset during the year ended December 31, 2025. As of March 31, 2026, the Company had $0.4 million of ROU assets, $0.3 million of current operating lease liabilities and $0.5 million of non-current operating lease liabilities related to the Boulder Lease.

The table below summarizes the Company’s operating lease costs for the three months ended March 31, 2026 and 2025 (in thousands except for lease terms and borrowing rates):


	Three Months Ended March 31,
	2026			2025
Operating lease costs:
Lease expense	$	48		$	609
Short-term lease expense	14			14
Variable lease expense	370			293
Total operating lease costs	$	432		$	916
Other information:
Operating cash flows used for operating leases	$	56		$	1,136
Weighted-average remaining lease term in years	3.6			2.4
Weighted-average incremental borrowing rate	6.84		%	6.73		%


2026 (nine months remaining)	$	253
2027	706
2028	642
2029	392
2030	200
Total lease payments	2,193
Less: amount representing imputed interest	(71)
Total future minimum lease obligations	$	2,122