License Agreement, Advances From Collaboration Partners, Legal and Other Contingencies	6 Months Ended
Jun. 30, 2026
Commitments and Contingencies Disclosure [Abstract]
License Agreement, Advances From Collaboration Partners, Legal and Other Contingencies	6. License Agreement, Advances From Collaboration Partners, Legal and Other Contingencies Almirall License Agreement and License and Service Revenue On March 11, 2024, the Company entered into the Almirall License Agreement with Almirall. Under the terms of the Almirall License Agreement, Almirall obtained global rights to develop and commercialize ZKN-013 for the potential treatment of rare dermatological and other diseases associated with nonsense mutations. In March 2025, Almirall informed the Company of its decision to not exercise the option for continued research and development services under the Almirall License Agreement, as permitted within the Almirall License Agreement, thereby relieving the Company of its remaining responsibilities under the Almirall License Agreement. The Company remains eligible to receive additional payments throughout the potential development phases, including development and sales milestones of up to approximately $470.0 million and tiered royalties based on any potential future global sales. During the three and six months ended June 30, 2026 and 2025, the Company recorded no license and service revenue from the Almirall License Agreement. Cystic Fibrosis Foundation As of June 30, 2026 and December 31, 2025, the Company recorded advances from collaboration partners in the accompanying unaudited condensed consolidated financial statements related to funding awards from the Cystic Fibrosis Foundation (“CFF”). The Company will be required to repay amounts received from the CFF in certain circumstances, including upon the successful commercialization of exaluren or any derivative products. During the three and six months ended June 30, 2026 and 2025, the Company received no funds from the CFF and made no payments to the CFF. In October 2025, the Company entered into an agreement with the CFF to amend a funding award (the “2025 CFF Amendment”), as amended on February 26, 2026, which reduced the royalty rate to less than one percent in exchange for a payment by the Company to CFF of $0.3 million. The Company is accounting for the $0.3 million payment as a debt discount, which is being amortized over a ten-year period. As of both June 30, 2026 and December 31, 2025, the unamortized debt discount was $0.3 million. Prior to October 2025, the funding awards included embedded derivatives arising from provisions that, upon the occurrence of a change of control or sale or license of funded assets (each a disposition event), the Company would be required to make payments to the CFF. The 2025 CFF Amendment terminated this requirement. With the termination of the embedded derivative-related terms under the 2025 CFF Amendment, the value of the related embedded derivatives was zero as of June 30, 2026 and December 31, 2025. Royalty Commitments to the IIA To date, the Company has received research and development grants from the Israel Innovation Authority (the “IIA”) totaling $2.6 million. No grants were received for the three and six months ended June 30, 2026 and 2025. Under the research and development agreements with the IIA and pursuant to applicable law, the Company is required to pay royalties at a low single-digit percentage on sales to end customers of product candidates developed with funds provided by the IIA, up to an amount equal to 100% of the IIA research and development grants received, plus interest. If the Company does not generate sales of product candidates developed with funds provided by the IIA, the Company is not obligated to pay royalties or repay the grants. As of June 30, 2026, the Company has not commenced the payment obligation of the royalties and has a contingent obligation with respect to royalty-bearing participation received or accrued amounting to $2.8 million, including accrued interest. Research and License Agreement with Technion Research and Development Foundation Ltd. ("TRDF") On August 29, 2013, the Company entered into the Research and License Agreement (the "Technion Agreement") with Technion Research and Development Foundation Ltd. ("TRDF"), which was further amended and supplemented to reflect, among other things, the assignment of patents and extension of research periods, with respect to certain technology relating to aminoglycosides and the redesign of aminoglycosides for the treatment of human genetic diseases caused by premature stop mutations and further results of the research of the technology, in order to develop and commercialize products based on such technology. Under the Technion Agreement, TRDF is obligated to provide the Company with research services for an estimated annual payment of $0.1 million, the precise amount to be agreed by the parties prior to the beginning of each year of the research period. During the three and six months ended June 30, 2026 and 2025, no expenses were incurred. As of June 30, 2026 and December 31, 2025, no amounts were recorded in accrued expenses. In addition, TRDF granted the Company a license to use, market, sell or sub-license the rights of the product developed under the TRDF research results (the “Licensed Product”), as fully defined in the Technion Agreement, for the following considerations: (i) aggregate milestone payments up to total consideration of $6.5 million; (ii) certain royalties in the low- to mid-single-digit percentage of net sales; and (iii) a mid-single to low-twenties percentage of any non-royalty sub-license income received by the Company from a sub-licensed entity. The Company made no milestone or royalty payments to the TRDF during the three and six months ended June 30, 2026 and 2025. License Agreement between Zikani and President and Fellows of Harvard College ("Harvard") On February 10, 2015, Zikani entered into an agreement with the President and Fellows of Harvard to license certain patent rights owned by Harvard. This license agreement was subsequently amended and restated on March 31, 2020 and further amended on July 17, 2024 (the "Harvard Agreement"). Under the Harvard Agreement, Harvard is entitled to receive clinical and regulatory milestone payments totaling up to $3.6 million in the aggregate per licensed product approved in the United States, European Union, and Japan. The Company is also obligated to make additional royalty payments to Harvard upon the occurrence of certain sales milestones per licensed product up to a mid-single digit royalty percentage, tiered non-royalty sublicense income payments of mid-single digit to low double-tens percentage of any sublicense income, and pay Harvard a percentage of income associated with transferring a priority review voucher from the FDA. Almirall has agreed to assume responsibility for the payment and performance obligations under the Harvard Agreement as sublicensee which ultimately depends on Almirall’s development and commercialization of ZKN-013. In addition to the license agreement, the Company also reimburses Harvard for certain costs related to the maintenance and further development of patents developed through the founding stockholder's research. During the three and six months ended June 30, 2026 and 2025, the Company incurred less than $0.1 million of patent expenses due to Harvard. Royalty and Revenue Sharing Agreement On July 10, 2024, as a condition of Domicilium’s entry into the sixth Hercules Amendment (the "Sixth Hercules Amendment") and in consideration of additional borrowings of $3.2 million from Domicilium, the borrowers and the Company entered into the Royalty Agreement, as amended on March 2, 2026. Capitalized terms under this heading “Royalty and Revenue Sharing Agreement” not otherwise defined herein have the definitions ascribed to them in the Royalty Agreement. Under the Royalty Agreement, the Company agreed to pay to Domicilium an amount equal to (i) (x) low-thirties percentage of the Development and Launch Milestone Payments for the several next occurring Development and Launch Milestone Events (as defined in the Almirall License Agreement), minus (y) the amounts required to be paid by the Company pursuant to certain vendors as defined in the Royalty Agreement, and (ii) (x) mid-twenties percentage of (1) each subsequent Development and Launch Milestone Payment plus (2) any Priority Review Voucher Income (as defined in the Almirall License Agreement) realized by Eloxx, less (y) any amount of such Development and Launch Milestone Payments which are due to Harvard University pursuant to the Harvard License Agreement, provided the aggregate amount paid to Domicilium shall not exceed an amount in the mid-double-digit millions. Each Milestone Sharing Payment shall be applied as a repayment or prepayment, as applicable, of the Loans (as defined in the Amended Loan Agreement) (including all interest and fees thereon) owed to Domicilium, if any such Loans remain outstanding. On January 3, 2025, the Company paid Domicilium $0.5 million related to Development and Launch Milestone Payments, in accordance with the terms of the Royalty Agreement, which was applied as a repayment of the Loans. The Royalty Agreement provides for an amount based on a percentage of the aggregate of (without duplication) the net sales, royalties and any other income or revenue realized by the Company solely related to or arising from the exaluren compound or any exaluren product, calculated in accordance with U.S. GAAP (collectively, the “exaluren Revenue”) (the “exaluren Revenue-Based Payment”). The exaluren Revenue-Based Payment with respect to each fiscal quarter shall be less than one percent of exaluren Revenue during the applicable fiscal quarter. Commencing on the ZKN-013 royalty commencement date, the Company promises to pay to Domicilium an amount based on a percentage of the aggregate of (without duplication) the net sales, royalties and any other income or revenue realized by the Company solely related to or arising from the ZKN-013 compound, calculated in accordance with U.S. GAAP (collectively, the “ZKN-013 Revenue”). The ZKN-013 revenue-based payment with respect to each fiscal quarter shall be less than one percent of ZKN-013 Revenue during the applicable fiscal quarter. The value of the royalty liability for the sales of future revenues was determined to be zero at issuance, at December 31, 2025, and at June 30, 2026, as royalty payments were considered to not be probable. Contingencies From time to time, the Company may become involved in various lawsuits and legal proceedings, which arise in the ordinary course of business. The Company is currently unaware of any material pending legal proceedings to which it is a party or of which its property is the subject. However, the Company may at times in the future become involved in litigation in the ordinary course of business, which may include actions related to or based on its intellectual property and its use, customer claims, employment practices and employee complaints and other events arising out of its operations. When appropriate in management’s estimation, the Company will record adequate reserves in its financial statements for pending litigation. Litigation is subject to inherent uncertainties, and an adverse result in any such matters could adversely impact its reputation, operations, and its financial operating results or overall financial condition. The Company accounts for contingent liabilities in accordance with ASC Topic 450, “Contingencies”. A provision is recorded when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to legal matters, provisions are reviewed and adjusted to reflect the impact of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter. As of June 30, 2026 and December 31, 2025, the Company was not a party to any litigation that is reasonably possible to have a material adverse effect on the Company’s business, financial position, results of operations or cash flows. Legal costs incurred in connection with loss contingencies are expensed as incurred.

License Agreement, Advances From Collaboration Partners, Legal and Other Contingencies

6 Months Ended

Jun. 30, 2026

Commitments and Contingencies Disclosure [Abstract]

License Agreement, Advances From Collaboration Partners, Legal and Other Contingencies

6. License Agreement, Advances From Collaboration Partners, Legal and Other Contingencies

Almirall License Agreement and License and Service Revenue

On March 11, 2024, the Company entered into the Almirall License Agreement with Almirall. Under the terms of the Almirall License Agreement, Almirall obtained global rights to develop and commercialize ZKN-013 for the potential treatment of rare dermatological and other diseases associated with nonsense mutations.

In March 2025, Almirall informed the Company of its decision to not exercise the option for continued research and development services under the Almirall License Agreement, as permitted within the Almirall License Agreement, thereby relieving the Company of its remaining responsibilities under the Almirall License Agreement. The Company remains eligible to receive additional payments throughout the potential development phases, including development and sales milestones of up to approximately $470.0 million and tiered royalties based on any potential future global sales.

During the three and six months ended June 30, 2026 and 2025, the Company recorded no license and service revenue from the Almirall License Agreement.

Cystic Fibrosis Foundation

As of June 30, 2026 and December 31, 2025, the Company recorded advances from collaboration partners in the accompanying unaudited condensed consolidated financial statements related to funding awards from the Cystic Fibrosis Foundation (“CFF”). The Company will be required to repay amounts received from the CFF in certain circumstances, including upon the successful commercialization of exaluren or any derivative products. During the three and six months ended June 30, 2026 and 2025, the Company received no funds from the CFF and made no payments to the CFF. In October 2025, the Company entered into an agreement with the CFF to amend a funding award (the “2025 CFF Amendment”), as amended on February 26, 2026, which reduced the royalty rate to less than one percent in exchange for a payment by the Company to CFF of $0.3 million. The Company is accounting for the $0.3 million payment as a debt discount, which is being

amortized over a ten-year period. As of both June 30, 2026 and December 31, 2025, the unamortized debt discount was $0.3 million.

Prior to October 2025, the funding awards included embedded derivatives arising from provisions that, upon the occurrence of a change of control or sale or license of funded assets (each a disposition event), the Company would be required to make payments to the CFF. The 2025 CFF Amendment terminated this requirement. With the termination of the embedded derivative-related terms under the 2025 CFF Amendment, the value of the related embedded derivatives was zero as of June 30, 2026 and December 31, 2025.

Royalty Commitments to the IIA

To date, the Company has received research and development grants from the Israel Innovation Authority (the “IIA”) totaling $2.6 million. No grants were received for the three and six months ended June 30, 2026 and 2025.

Under the research and development agreements with the IIA and pursuant to applicable law, the Company is required to pay royalties at a low single-digit percentage on sales to end customers of product candidates developed with funds provided by the IIA, up to an amount equal to 100% of the IIA research and development grants received, plus interest. If the Company does not generate sales of product candidates developed with funds provided by the IIA, the Company is not obligated to pay royalties or repay the grants.

As of June 30, 2026, the Company has not commenced the payment obligation of the royalties and has a contingent obligation with respect to royalty-bearing participation received or accrued amounting to $2.8 million, including accrued interest.

Research and License Agreement with Technion Research and Development Foundation Ltd. ("TRDF")

On August 29, 2013, the Company entered into the Research and License Agreement (the "Technion Agreement") with Technion Research and Development Foundation Ltd. ("TRDF"), which was further amended and supplemented to reflect, among other things, the assignment of patents and extension of research periods, with respect to certain technology relating to aminoglycosides and the redesign of aminoglycosides for the treatment of human genetic diseases caused by premature stop mutations and further results of the research of the technology, in order to develop and commercialize products based on such technology. Under the Technion Agreement, TRDF is obligated to provide the Company with research services for an estimated annual payment of $0.1 million, the precise amount to be agreed by the parties prior to the beginning of each year of the research period. During the three and six months ended June 30, 2026 and 2025, no expenses were incurred. As of June 30, 2026 and December 31, 2025, no amounts were recorded in accrued expenses.

In addition, TRDF granted the Company a license to use, market, sell or sub-license the rights of the product developed under the TRDF research results (the “Licensed Product”), as fully defined in the Technion Agreement, for the following considerations: (i) aggregate milestone payments up to total consideration of $6.5 million; (ii) certain royalties in the low- to mid-single-digit percentage of net sales; and (iii) a mid-single to low-twenties percentage of any non-royalty sub-license income received by the Company from a sub-licensed entity. The Company made no milestone or royalty payments to the TRDF during the three and six months ended June 30, 2026 and 2025.

License Agreement between Zikani and President and Fellows of Harvard College ("Harvard")

On February 10, 2015, Zikani entered into an agreement with the President and Fellows of Harvard to license certain patent rights owned by Harvard. This license agreement was subsequently amended and restated on March 31, 2020 and further amended on July 17, 2024 (the "Harvard Agreement"). Under the Harvard Agreement, Harvard is entitled to receive clinical and regulatory milestone payments totaling up to $3.6 million in the aggregate per licensed product approved in the United States, European Union, and Japan. The Company is also obligated to make additional royalty payments to Harvard upon the occurrence of certain sales milestones per licensed product up to a mid-single digit royalty percentage, tiered non-royalty sublicense income payments of mid-single digit to low double-tens percentage of any sublicense income, and pay Harvard a percentage of income associated with transferring a priority review voucher from the FDA.

Almirall has agreed to assume responsibility for the payment and performance obligations under the Harvard Agreement as sublicensee which ultimately depends on Almirall’s development and commercialization of ZKN-013.

In addition to the license agreement, the Company also reimburses Harvard for certain costs related to the maintenance and further development of patents developed through the founding stockholder's research. During the three and six months ended June 30, 2026 and 2025, the Company incurred less than $0.1 million of patent expenses due to Harvard.

Royalty and Revenue Sharing Agreement

On July 10, 2024, as a condition of Domicilium’s entry into the sixth Hercules Amendment (the "Sixth Hercules

Amendment") and in consideration of additional borrowings of $3.2 million from Domicilium, the borrowers and the Company entered into the Royalty Agreement, as amended on March 2, 2026. Capitalized terms under this heading “Royalty and Revenue Sharing Agreement” not otherwise defined herein have the definitions ascribed to them in the Royalty Agreement.

Under the Royalty Agreement, the Company agreed to pay to Domicilium an amount equal to (i) (x) low-thirties percentage of the Development and Launch Milestone Payments for the several next occurring Development and Launch Milestone Events (as defined in the Almirall License Agreement), minus (y) the amounts required to be paid by the Company pursuant to certain vendors as defined in the Royalty Agreement, and (ii) (x) mid-twenties percentage of (1) each subsequent Development and Launch Milestone Payment plus (2) any Priority Review Voucher Income (as defined in the Almirall License Agreement) realized by Eloxx, less (y) any amount of such Development and Launch Milestone Payments which are due to Harvard University pursuant to the Harvard License Agreement, provided the aggregate amount paid to Domicilium shall not exceed an amount in the mid-double-digit millions. Each Milestone Sharing Payment shall be applied as a repayment or prepayment, as applicable, of the Loans (as defined in the Amended Loan Agreement) (including all interest and fees thereon) owed to Domicilium, if any such Loans remain outstanding. On January 3, 2025, the Company paid Domicilium $0.5 million related to Development and Launch Milestone Payments, in accordance with the terms of the Royalty Agreement, which was applied as a repayment of the Loans.

The Royalty Agreement provides for an amount based on a percentage of the aggregate of (without duplication) the net sales, royalties and any other income or revenue realized by the Company solely related to or arising from the exaluren compound or any exaluren product, calculated in accordance with U.S. GAAP (collectively, the “exaluren Revenue”) (the “exaluren Revenue-Based Payment”). The exaluren Revenue-Based Payment with respect to each fiscal quarter shall be less than one percent of exaluren Revenue during the applicable fiscal quarter. Commencing on the ZKN-013 royalty commencement date, the Company promises to pay to Domicilium an amount based on a percentage of the aggregate of (without duplication) the net sales, royalties and any other income or revenue realized by the Company solely related to or arising from the ZKN-013 compound, calculated in accordance with U.S. GAAP (collectively, the “ZKN-013 Revenue”). The ZKN-013 revenue-based payment with respect to each fiscal quarter shall be less than one percent of ZKN-013 Revenue during the applicable fiscal quarter. The value of the royalty liability for the sales of future revenues was determined to be zero at issuance, at December 31, 2025, and at June 30, 2026, as royalty payments were considered to not be probable.

Contingencies

From time to time, the Company may become involved in various lawsuits and legal proceedings, which arise in the ordinary course of business. The Company is currently unaware of any material pending legal proceedings to which it is a party or of which its property is the subject. However, the Company may at times in the future become involved in litigation in the ordinary course of business, which may include actions related to or based on its intellectual property and its use, customer claims, employment practices and employee complaints and other events arising out of its operations. When appropriate in management’s estimation, the Company will record adequate reserves in its financial statements for pending litigation. Litigation is subject to inherent uncertainties, and an adverse result in any such matters could adversely impact its reputation, operations, and its financial operating results or overall financial condition.

The Company accounts for contingent liabilities in accordance with ASC Topic 450, “Contingencies”. A provision is recorded when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. With respect to legal matters, provisions are reviewed and adjusted to reflect the impact of negotiations, estimated settlements, legal rulings, advice of legal counsel and other information and events pertaining to a particular matter. As of June 30, 2026 and December 31, 2025, the Company was not a party to any litigation that is reasonably possible to have a material adverse effect on the Company’s business, financial position, results of operations or cash flows. Legal costs incurred in connection with loss contingencies are expensed as incurred.