4. Current liabilities

Clinical trial accrued liabilities

Clinical trial accrued liabilities was $2.8 million as of June 30, 2026 as compared to $0.1 million as of December 31, 2025. The increase of $2.7 million was due to timing of when the third-party clinical research organization (“CRO”) invoices us for services performed by the CRO. Additionally, the overall increase in clinical trial accrued liabilities reflects increased R&D activities in 2026 related to the Phase 1 clinical trial for DA-1726.

Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consist of the following (in thousands):

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Warrant liabilities

Changes to our warrant liabilities are summarized as follows (in thousands):

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Our warrant liabilities relate to the 2022 Series B warrants, which were issued in November 2022. These warrants are considered to be derivative instruments; accordingly, we recorded their estimated fair value as warrant liabilities. We estimated the fair value of these warrants using the trading market price of our common stock due to a cashless exercise provision of these warrants whereby eight warrants can be exercised for one share of common stock for no additional consideration, which results in an effective per warrant exercise price of zero.