In October 2020, the Company became party to a license agreement (the “ImmunoGen License Agreement”) with Immunogen, Inc. (“ImmunoGen”), under which the Company obtained an exclusive, sublicensable, worldwide license to certain patents and other intellectual property rights to develop, manufacture, and commercialize certain products for non-oncology and non-radiopharmaceutical indications. In consideration for rights granted by ImmunoGen, the Company is obligated to make certain future development milestone payments of up to $48.0 million upon the achievement of specified clinical and regulatory milestones. In December 2021, the Company paid a $2.5 million milestone payment to ImmunoGen upon the submission of an IND application for veligrotug with the FDA. In May 2022, the Company paid a $3.0 million milestone payment to ImmunoGen related to the first patient dosed in the clinical trial for veligrotug. In December 2022, the Company recorded $10.0 million as research and development expense related to a milestone owed to ImmunoGen related to the first patient dosed in a pivotal clinical trial for veligrotug, which was paid in January 2023. Additionally, if the Company successfully commercializes any product candidate subject to the ImmunoGen License Agreement, it is responsible for royalty payments equal to a percentage in the mid-single digits of net sales and commercial milestone payments of up to $95.0 million. The Company is obligated to make any such royalty payments on a product-by-product and country-by-country basis from the first commercial sale of a specified product in each country until the later of (i) the expiration of the last patent claim subject to the ImmunoGen License Agreement in such country, (ii) the expiration of any applicable regulatory exclusivity obtained for each product in such country, or (iii) the 12th anniversary of the date of the first commercial sale of such product in such country. On February 12, 2024, AbbVie Inc. acquired ImmunoGen. The terms of the ImmunoGen License Agreement did not change as a result of this acquisition.

In January 2023, the Company entered into a Development and License Agreement (the “Enable License Agreement”) with Enable Injections, Inc. (“Enable”), under which Enable granted the Company an exclusive, royalty-bearing, sublicensable, non-transferrable license to (i) develop, commercialize, seek marketing approval for and otherwise use and exploit certain products, and (ii) make and have made such product solely for such permitted uses. Pursuant to the terms of the Enable License Agreement, the Company granted Enable a non-exclusive, royalty-free, non-sublicensable, non-transferable license. In

The Company is obligated to make certain future milestone payments of up to $45.0 million upon the achievement of specified development, clinical and regulatory milestones. Additionally, if the Company is successful in commercializing any product candidate subject to the Enable License Agreement, the Company is obligated to make certain commercial milestone payments of up to $150.0 million and royalty payments equal to a percentage in the mid-single digits.

In accordance with the merger agreement with miRagen Therapeutics, Inc. (“miRagen”), on November 4, 2020, the Company entered into a contingent value rights agreement (the “CVR Agreement”), pursuant to which each holder of the Company’s common stock as of November 6, 2020, other than former stockholders of the private entity Viridian Therapeutics, Inc. (which merged with miRagen), received one contingent value right (a “CVR”) for each share of Company common stock held by such holder on that date. Under the CVR Agreement, holders of CVRs would have been entitled to receive a portion of the net proceeds for any dispositions of certain legacy miRagen assets consummated through December 31, 2021. As of December 31, 2021, the disposition period had expired. There were no dispositions of any such legacy assets prior to that time and, accordingly, there will be no payments made under the CVR Agreement. The CVR Agreement expires on November 4, 2025.

In May 2023, the Company and a third-party collaborator entered into an Exclusive License and Collaboration Agreement to collaborate and conduct certain IND-enabling activities with respect to the licensed compound and licensed product. Under the terms of the agreement, the Company was granted an exclusive, royalty-bearing, worldwide license to develop, manufacture, and commercialize certain licensed compounds and licensed products in the field (the “License”). In consideration for the rights granted by the License, the Company issued 243,902 shares of its common stock to certain stockholders of the third-party. The shares were valued at $5.7 million and recorded as research and development expense during the year ended December 31, 2023. Additionally, upon the date when the Company decided to pursue certain studies for the licensed compound under the agreement, the Company was obligated to issue the third-party collaborator the equivalent of $10.0 million in shares of its common stock. The Company was also obligated to make certain future milestones of up to $45.0 million upon the achievement of certain development milestones. Remaining development milestone payments would have been payable in cash. If the Company was successful in commercializing products related to the licensed compound, the Company was also obligated to pay up to $60.0 million upon the achievement of certain sales milestones as well as royalty payments equal to a percentage in the mid-single to double digits. This agreement was terminated on December 30, 2024, and no further financial obligations exist under the Exclusive License and Collaboration Agreement.

The Company is party to a multi-year, non-cancelable lease agreement for its Colorado-based office and lab space (the “Colorado Lease”). The Colorado Lease includes rent escalation clauses through the lease term and a Company option to extend the lease term for up to three terms of three years each. Minimum base lease payments under the Colorado Lease, including the impact of tenant improvement allowances, are recognized on a straight-line basis over the full term of the lease. The lease term was amended in March 2021 to extend the lease maturity date to December 31, 2024. Upon adoption of ASC 842 and upon subsequent modification of the lease in 2020 and in March 2021, the Company recognized a right-of-use asset and corresponding lease liability for the Colorado Lease of approximately $1.6 million by calculating the present value of lease payments, discounted at 6%, the Company’s estimated incremental borrowing rate, over the 12 months expected remaining term.

In September 2024, the Company entered into a new, multi-year lease agreement for its Colorado-based office and lab space (the “New Colorado Lease”). Under ASC 842, the New Colorado Lease was treated as a lease modification representing an extension of the lease term for a reduced portion of the space currently in use under the existing Colorado Lease. As of the effective date, the Company recorded a $0.3 million increase in the right-of-use asset and corresponding lease liability for the extension of the lease term. The remaining space under the Colorado Lease terminated at the original maturity date of December 31, 2024. The New Colorado Lease provides for annual base rent of approximately $0.1 million during the lease term. The Company is also obligated to pay the landlord certain costs, taxes, and operating expenses. The New Colorado Lease is set to expire in December 2026. The Company has the option to extend the lease term for an additional period of five years

The Company is party to a multi-year, non-cancelable lease agreement for its Massachusetts-based office space (as subsequently amended in July 2021, April 2022, July 2022, April 2024 and September 2024, the “Massachusetts Lease”). The Massachusetts Lease includes rent escalation clauses throughout the lease term. Minimum base lease payments under the Massachusetts Lease are recognized on a straight-line basis over the full term of the Massachusetts Lease. Upon initial assumption of the Massachusetts Lease in October 2020, the Company recognized a right-of-use asset and corresponding lease liability of $0.1 million by calculating the present value of lease payments, discounted at 6%, the Company’s estimated incremental borrowing rate, over the expected remaining term.

In April 2024, the Company entered into a Fourth Amendment of the Massachusetts Lease (the “Fourth Amendment”). The Fourth Amendment makes certain modifications to the Massachusetts Lease, including (i) securing 10,427 square feet of office space in a new building suite (the “New Premises”), (ii) the termination of the 10,956 square feet of leased space under the existing Massachusetts Lease (the “Original Premises”), and (iii) the extension of the expiration date of the leased space to five years from the delivery of the New Premises. The Massachusetts Lease provides for annual base rent of approximately $0.5 million during the lease term. The Company is also obligated to pay the landlord certain costs, taxes and operating expenses. Under the Fourth Amendment, the Massachusetts Lease will expire in July 2029. The Company has the option to extend the lease term for an additional period of three years upon notice to the landlord. The option to extend is not included in the lease term assessment as it is not reasonably certain the Company will exercise the option.

In September 2024, the Company entered into a Fifth Amendment of the Massachusetts Lease (the “Fifth Amendment”) to lease an additional 2,788 square feet of office space in the same building. The Fifth Amendment provides for additional annual base rent of approximately $0.1 million for the additional office space and includes annual base rent escalation clauses during the lease term. The Fifth Amendment was treated as a lease modification accounted for as a separate contract and the Company recorded a new right-of-use asset and corresponding lease liability of approximately $0.5 million related to the Fifth Amendment on the lease commencement date.

As of March 31, 2025, the Company’s operating lease obligations were reflected as short-term operating lease liabilities of $0.5 million within accrued liabilities and $1.9 million of long-term lease obligations as other liabilities in the Company’s condensed consolidated balance sheets. As of March 31, 2025, the weighted average remaining lease term was 4.1 years and the weighted average incremental borrowing rate used to determine the operating lease liability was 9.3%.