Commitments, contingencies, and other liabilities	12 Months Ended
Dec. 31, 2025
Commitments, contingencies, and other liabilities
Commitments, contingencies, and other liabilities	8. Commitments, contingencies, and other liabilities Other Agreements In 2016, the Company entered into a research and development funding arrangement with a non-profit organization that provided up to $4.0 million in funding to the Company upon the achievement of clinical and development milestones. The agreement as amended in 2022 provides that the Company is obligated to repay amounts received under certain circumstances, including termination of the agreement, and to pay an amount up to 2.6 times the funding received upon successful development and commercialization of any products developed. In 2017, the Company earned a milestone payment of $1.0 million. The Company evaluated the arrangement and concluded that it represents a research and development financing arrangement as it is probable that the Company will repay amounts received under the arrangement. As a result, the $1.0 million is recorded as a non-current liability in the consolidated balance sheet. In November 2022, the Company and Touchlight IP Limited (“Touchlight”) entered into a license agreement (the “Touchlight License Agreement”) to authorize historical use by the Company of a certain DNA preparation process ( the “Subject DNA Preparation Process”), and to authorize the prospective exploitation of TRACER Capsids created with the use of the Subject DNA Preparation Process. The terms of the Touchlight License Agreement include future milestone payments and low single-digit royalties payable to Touchlight by the Company if the Company or its program collaborators or licensees choose to utilize in a therapeutic product certain TRACER Capsids that were created with the historical use of the Subject DNA Preparation Process. Additionally, the Company is obligated to pay low single-digit royalties to Touchlight on future payments it receives in connection with licensing of certain TRACER Capsids that were created with the historical use of the Subject DNA Preparation Process, excluding the licensing of or collaboration on any of the Company’s therapeutic programs. In June 2025, the Company and Transition Bio, Inc. (“Transition Bio”) entered into a license agreement (the “Transition Bio License Agreement”) under which Transition Bio is responsible for the discovery and optimization of small molecules targeting TDP-43 until nomination of a development candidate, upon which the Company will have an option to license the worldwide exclusive rights to develop and commercialize the program. The Transition Bio License Agreement contains a termination for convenience clause, which allows for either party to terminate the arrangement for any reason or no reason upon sixty days’ prior written notice. The Transition Bio License Agreement superseded a prior agreement between the Company and Transition Bio dated December 24, 2024. In the event that the Company terminates the Transition Bio License Agreement due to a change in control, the Company is obligated to pay Transition Bio up to $2.0 million in termination fees. In connection with a prior agreement between the parties, the Company paid Transition Bio a low single-digit million dollar upfront payment, which was expensed as research and development expense in the year ended December 31, 2024. Additionally, during the fourth quarter of 2025, the Company paid Transition Bio a low single-digit million dollar payment for the achievement of a research milestone, which was also expensed as research and development expense during the year ended December 31, 2025. The terms of the Transition Bio License Agreement include future payments based on potential research, development, commercial and net sales milestones. Additionally, the Company is obligated to pay high single-digit to low double-digit royalties to Transition Bio on net sales during the royalty term of up to ten years. Litigation The Company was not a party to any material legal matters or claims and did not have contingency reserves established for any litigation liabilities as of December 31, 2025, or 2024.

Commitments, contingencies, and other liabilities

12 Months Ended

Dec. 31, 2025

Commitments, contingencies, and other liabilities

Commitments, contingencies, and other liabilities

8. Commitments, contingencies, and other liabilities

Other Agreements

In 2016, the Company entered into a research and development funding arrangement with a non-profit organization that provided up to $4.0 million in funding to the Company upon the achievement of clinical and development milestones. The agreement as amended in 2022 provides that the Company is obligated to repay amounts received under certain circumstances, including termination of the agreement, and to pay an amount up to 2.6 times the funding received upon successful development and commercialization of any products developed. In 2017, the Company earned a milestone payment of $1.0 million. The Company evaluated the arrangement and concluded that it represents a research and development financing arrangement as it is probable that the Company will repay amounts received under the arrangement. As a result, the $1.0 million is recorded as a non-current liability in the consolidated balance sheet.

In November 2022, the Company and Touchlight IP Limited (“Touchlight”) entered into a license agreement (the “Touchlight License Agreement”) to authorize historical use by the Company of a certain DNA preparation process ( the “Subject DNA Preparation Process”), and to authorize the prospective exploitation of TRACER Capsids created with the use of the Subject DNA Preparation Process. The terms of the Touchlight License Agreement include future milestone payments and low single-digit royalties payable to Touchlight by the Company if the Company or its program collaborators or licensees choose to utilize in a therapeutic product certain TRACER Capsids that were created with the historical use of the Subject DNA Preparation Process. Additionally, the Company is obligated to pay low single-digit royalties to Touchlight on future payments it receives in connection with licensing of certain TRACER Capsids that were created with the historical use of the Subject DNA Preparation Process, excluding the licensing of or collaboration on any of the Company’s therapeutic programs.

In June 2025, the Company and Transition Bio, Inc. (“Transition Bio”) entered into a license agreement (the “Transition Bio License Agreement”) under which Transition Bio is responsible for the discovery and optimization of small molecules targeting TDP-43 until nomination of a development candidate, upon which the Company will have an option to license the worldwide exclusive rights to develop and commercialize the program. The Transition Bio License Agreement contains a termination for convenience clause, which allows for either party to terminate the arrangement for any reason or no reason upon sixty days’ prior written notice. The Transition Bio License Agreement superseded a prior agreement between the Company and Transition Bio dated December 24, 2024. In the event that the Company terminates the Transition Bio License Agreement due to a change in control, the Company is obligated to pay Transition Bio up to $2.0 million in termination fees.

In connection with a prior agreement between the parties, the Company paid Transition Bio a low single-digit million dollar upfront payment, which was expensed as research and development expense in the year ended December 31, 2024. Additionally, during the fourth quarter of 2025, the Company paid Transition Bio a low single-digit million dollar payment for the achievement of a research milestone, which was also expensed as research and development expense during the year ended December 31, 2025. The terms of the Transition Bio License Agreement include future payments based on potential research, development, commercial and net sales milestones. Additionally, the Company is obligated to pay high single-digit to low double-digit royalties to Transition Bio on net sales during the royalty term of up to ten years.

Litigation

The Company was not a party to any material legal matters or claims and did not have contingency reserves established for any litigation liabilities as of December 31, 2025, or 2024.