6. Fair Value Measurements

The Company records its financial assets and liabilities at fair value. The carrying amounts of certain of the Company’s financial instruments, including cash, trade and other receivables, net, and accounts payable, approximate their fair value due to their short maturities. Fair value is defined as the exchange price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The accounting guidance for fair value establishes a framework for measuring fair value and a fair value hierarchy that prioritizes the inputs used in valuation techniques. The accounting standard describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value which are the following:

Level 1 – Observable inputs, such as unadjusted quoted prices in active markets for identical assets or liabilities.

Level 2 – Observable inputs, either directly or indirectly, other than quoted prices in active markets for identical assets or liabilities, such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities; therefore, requiring an entity to develop its own valuation techniques and assumptions.

An entity may choose to measure many financial instruments and certain other items at fair value at specified election dates. The Company’s Exarafenib milestone asset (Note 4) was carried at fair value, determined according to Level 3 inputs in the fair value hierarchy described above. Any subsequent changes in the estimated fair value of the Exarafenib milestone asset are recorded in the condensed consolidated statements of operations.

The following tables set forth the Company’s fair value hierarchy for its financial assets and liabilities measured at fair value on a recurring basis as follows (in thousands):

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Exarafenib Milestone Asset and Exarafenib Milestone Contingent Consideration

The Exarafenib milestone asset and Exarafenib milestone contingent consideration represent the Company’s potential receipt of a future milestone payment and a future consideration payable to Kinnate CVR holders that are contingent upon the achievement of a certain specified milestone related to the Exarafenib sale. As of March 31, 2025, the estimated fair value of each of the Exarafenib milestone asset and Exarafenib milestone contingent consideration was $3.3 million. The fair value measurement was based on a probability-weighted discounted cash flow model using significant Level 3 inputs, such as anticipated timelines and the probability of achieving the development milestone. Both the Exarafenib milestone asset and Exarafenib milestone contingent consideration are remeasured at fair value at each reporting period with changes in fair value recorded in the other income (expense), net line item of the condensed consolidated statement of operations until settlement.

During the three months ended March 31, 2025, the estimated fair value of both the Exarafenib milestone asset and Exarafenib milestone contingent consideration increased by $0.1 million. The increase in estimated fair value had no offsetting net impact on the condensed consolidated statements of operations for the three months ended March 31, 2025.

Castle Creek PRV Interest and Warrants

The Castle Creek PRV Interest and warrants represent the Company's right to receive 6.7% of the proceeds from a potential Priority Review Voucher sale and warrants to purchase Castle Creek's Series D-1 Preferred Stock, acquired as part of the Castle Creek royalty financing transaction on February 24, 2025. As of March 31, 2025, the estimated fair value of the Castle Creek PRV Interest was nominal, and the estimated fair value of the Castle Creek warrants was $0.6 million. The fair value measurement for the PRV Interest was based on a probability-weighted discounted cash flow model, while the warrants were valued using a Black-Scholes option pricing model. Both valuations used significant Level 3 inputs, including expected timing of FDA approval, probability of PRV issuance and sale, expected volatility, risk-free interest rates, and discount rates reflecting the risk associated with Castle Creek's development program. Both the Castle Creek PRV Interest and warrants are remeasured at fair value at each reporting period with changes in fair value recorded in the other income (expense), net line item of the condensed consolidated statement of operations.

Equity Securities

The equity securities consisted of investments in public traded companies’ common stock that are classified on the condensed consolidated balance sheets as current assets as of March 31, 2025 and December 31, 2024. The equity securities are revalued each reporting period with changes in fair value recorded in the other income (expense), net line item of the condensed consolidated statements of operations. The inputs that were used to calculate the fair value of the equity securities were observable prices in active markets and therefore were classified as a Level 1 fair value measurement.