6. Leases

The Company leases real estate, primarily laboratory, office and manufacturing space. The Company’s leases have remaining terms ranging from less than one year to ten years. One of the Company's leases includes an option to renew, exercisable at the Company’s sole discretion, with renewal terms that can extend the lease for up to ten years. The Company previously evaluated the renewal options in its leases to determine if it was reasonably certain that the renewal option would be exercised. Given the Company’s current business structure, uncertainty of future growth, and the associated impact to real estate, the Company concluded that it is not reasonably certain that any renewal options would be exercised. Therefore, the operating lease assets and operating lease liabilities only contemplate the initial lease terms. All the Company’s leases qualify as operating leases.

In June 2026, in order to reduce the Company's ongoing annual rent costs and facilities footprint, the Company entered into the First Amendment to Lease (the “Lease Amendment”) with 101 CPD LLC (f/k/a HCP/King 101 CPD LLC), a Delaware limited liability company (the “Landlord”), which amends the Lease Agreement, dated September 22, 2021, by and between the Company and the Landlord (as amended, the “Lease”), pursuant to which the Company leases approximately 82,714 rentable square feet of office and laboratory space in Cambridge, Massachusetts.

Effective as of May 1, 2026, the Lease Amendment reduced the amount of space subject to the lease from 82,714 rentable square feet of space to 36,882 rentable square feet, extended the term of the renewal premises to December 31, 2036, and reduced the base rent the Company is obligated to pay the Landlord for the renewal premises to $79.70 per rentable square foot per year, subject to an annual adjustment of 3%. Concurrent with the execution of the Lease Amendment, the Company entered into a separate lease for the portion of the space under the Lease that was not retained (the “Early Termination Premises”) with a lease term that ends on December 31, 2027. There are no ongoing legal or economic liabilities of the Company related to this lease of the Early Termination Premises apart from the termination payments described below related to the Lease Amendment. The Company accounted for the Lease Amendment and the lease of the Early Termination Premises as a single contract with two lease components, as the agreements were negotiated simultaneously.

As consideration for the Lease Amendment, the Company agreed to pay the following: (i) a $4,500 termination fee payable on the execution of the Lease Amendment, and (ii) on or before January 4, 2027, a deferred payment of $5,201 which may be satisfied either as an unconditional letter of credit or in cash, of which $1,967 represents the Company’s rent obligations for the period from May 1, 2026 through December 31, 2026 and $3,234 represents an additional termination payment. Further, the Company permitted the Landlord to draw the existing letter of credit held by Landlord under the Lease equal to $6,266. Minimum lease payments total $36,763 throughout the term of the Lease Amendment, for total consideration of $50,763 inclusive of termination fees and the letter of credit draw. The Company identified two lease components, the retained space subject to the Lease Amendment, and the Early Termination Premises. Consideration was allocated to each lease component based on their relative standalone selling prices.

The Company accounted for the Lease Amendment as a modification to the existing lease and not a new contract separate from the existing contract, and accordingly decreased the associated lease liability and right-of-use asset by $11,538.

During the nine months ended September 30, 2026, the Company identified an indicator of impairment relating to the Early Termination Premises, as the Company is not planning to use the Early Termination Premises; additionally, the Company is prohibited under the lease from marketing the Early Termination Premises for sublease. The Company determined that this represents a significant adverse change in the extent in which the long-lived asset was being used. The Company concluded that the carrying value

of the Early Termination Premises, which represents a single asset group, was not recoverable as there are zero future cash flows that are expected to be generated from the assets within the asset group. The Company recognized an impairment loss of $5,807, consisting of $5,574 on the operating lease right-of-use asset and $233 on the leasehold improvements, in the nine months ended September 30, 2026. The impairment loss is disaggregated in the accompanying condensed consolidated statements of operations and comprehensive income (loss) as a separate line, impairment of long-lived assets.

On July 31, 2026, the Company entered into the Third Amendment to Lease and Termination Agreement (the “Termination Agreement”) with BMR-Sidney Research Campus LLC, a Delaware limited liability company (the “Sidney Street Landlord”), the purpose of which is to effect an early termination of one of the Company’s leases, reducing the Company’s ongoing annual facilities costs and materially eliminating the Company’s primary restoration obligations. The Termination Agreement amends the Lease Agreement, dated November 11, 2015, by and between the Company and the Sidney Street Landlord (as amended, the “Sidney Street Lease”), pursuant to which the Company leases approximately 68,636 rentable square feet of office, laboratory, and manufacturing space located at 200 Sidney Street, Cambridge, Massachusetts (the “Existing Premises”).

The Termination Agreement provides for (i) effective as of August 1, 2026, the surrender by the Company to the Sidney Street Landlord of an aggregate area of approximately 21,295 rentable square feet of the Existing Premises (the “Sidney Early Termination Premises”), and (ii) the revision of the expiration date of the term of the Lease with respect to the remaining 47,341 rentable square feet of the Existing Premises (the “Renewal Premises”) from January 13, 2031 to December 31, 2026. As consideration for the Termination Agreement, the Company agreed to pay the following: (i) an increase to the letter of credit held by the Sidney Street Landlord in the amount of $2,238 (for a total letter of credit of $3,638), which the Sidney Street Landlord will apply toward rent and operating expenses through the term of the Renewal Premises, (ii) on or before January 4, 2027, a termination payment of $3,850, and (iii) an equity issuance of shares of the Company's common stock valued at $500 (the “Share Issuance”).

On July 31, 2026, in connection with the Share Issuance, the Company entered into a Stock Issuance Agreement (the “Stock Issuance Agreement”) with the Sidney Street Landlord, pursuant to which the Company agreed to issue 103,520 shares of Common Stock (the “Shares”) to the Sidney Street Landlord at a price per share of $4.83, which was the closing price of the Common Stock on the Nasdaq Global Select Market (“Nasdaq”) on July 31, 2026. The Shares are registered under the Company’s registration statement on Form S-3 (File No. 333-273794), pursuant to a prospectus supplement, dated July 31, 2026 and the accompanying base prospectus, dated August 15, 2023, and were freely tradeable when issued. The Stock Issuance Agreement contains customary representations and warranties of the Company and the Sidney Street Landlord and customary conditions to the share issuance.

The reduction of the lease term and associated lease payments for the Renewal Premises does not grant the Company an additional right-of-use, so it is therefore accounted for as a modification to the existing lease and not a new contract separate from the existing contract. Accordingly, the Company remeasured the lease liability to account for the remaining lease payments, inclusive of the letter of credit, the future termination payment, and the equity issuance, over the remaining lease term and decreased the associated lease liability and right-of-use asset by $18,884.

During the three months ended September 30, 2026, the Company identified an indicator of impairment relating to the Renewal Premises, as the Company fully exited the Renewal Premises concurrent with the Termination Agreement; additionally, given the reduced lease term of five months from the date the Termination Agreement was executed, the Company is unable to sublease the Renewal Premises. The Company determined that this represents a significant adverse change in the extent to which the long-lived asset was being used. The Company concluded that the carrying value of the Renewal Premises, which represents a single asset group, was not recoverable and the fair value of the asset group is zero. The Company recognized an impairment loss of $5,705, consisting of $3,654 on the operating lease right-of-use asset and $2,051 on the leasehold improvements, in the three and nine months ended September 30, 2026. The impairment loss is disaggregated in the accompanying condensed consolidated statements of operations and comprehensive income (loss) as a separate line, impairment of long-lived assets.

Concurrent with the Termination Agreement, the Company assigned its existing sublease for the Sidney Early Termination Premises to the Sidney Street Landlord. As a result, the Company concluded that the remaining straight-line sublease receivable would not be realized and recognized a loss of $469 upon termination of the sublease, which is included within other income (expense) in the accompanying condensed consolidated statements of operations and comprehensive income (loss).

During the three and nine months ended September 30, 2026 and 2025, the Company made cash payments for operating leases of $2,584, $21,731, $4,837, and $14,552, respectively.