Failure to Satisfy Listing Rule (Form 8-K)

On June 3, 2025, Plus Therapeutics, Inc. (the "Company") received a letter from the Nasdaq Listing Qualifications Department (the "Staff") of The Nasdaq Stock Market LLC ("Nasdaq") stating that the Company had regained compliance with the Rule 5250(c)(1) due to filing its Quarterly Report on Form 10-Qfor the period ended March 31, 2025 (the "Quarterly Report") with the U.S. Securities and Exchange Commission (the "SEC") on May 30, 2025.

As previously disclosed, on March 8, 2024, the Company received a written notice from the Staff, notifying the Company that it no longer complied with the requirement under Nasdaq Listing Rule 5550(b)(1) to maintain a minimum of $2.5 million in stockholders' equity (the "Minimum Stockholders' Equity Requirement") for continued listing on The Nasdaq Capital Market or the alternative requirements of having a market value of listed securities of $35 million or net income from continuing operations of $500,000 in the most recently completed fiscal year or two of the last three most recently completed fiscal years.

On March 7, 2025, the Company received notification from Nasdaq that it had regained compliance with the Minimum Stockholders' Equity Requirement and was subject to a Mandatory Panel Monitor until March 7, 2026.

On June 3, 2025, the Staff notified the Company that it was not in compliance with the Minimum Stockholders' Equity Requirement (the "June 3 Letter"). The Company reported stockholders' equity (deficit) of ($23,641,000) in its Quarterly Report on Form 10-Qfor the period ended March 31, 2025, and, as a result, did not satisfy the Minimum Stockholders' Equity Requirement pursuant to Listing Rule 5550(b)(1). As a result, the Staff determined to delist the Company's securities from Nasdaq, unless the Company timely requests an appeal of the Staff's determination to a Hearings Panel (the "Panel"), pursuant to the procedures set forth in the Nasdaq Listing Rule 5800 Series. The Company must request a hearing no later than 4:00 p.m. Eastern Time on June 10, 2025.

The Company plans to request a hearing before the Panel to appeal the June 3 Letter and to address all outstanding matters, including compliance with the Minimum Stockholders' Equity Requirement, which hearing date has not been set as of the date of this Current Report on Form 8-K(this "Form 8-K").While the appeal process is pending, the suspension of trading of the Company's common stock, par value $0.001 per share (the "Common Stock"), will be stayed and the Common Stock will continue to trade on the Nasdaq Capital Market until the hearing process has concluded and the Panel issues a written decision. The Company has been informed that hearings are typically scheduled to occur approximately 30-45days after the date of the hearing request. There can be no assurance, however, that the Panel will grant the Company's request for continued listing or that the Company will be able to demonstrate compliance with Nasdaq Listing Rule 5550(b)(1) within any additional compliance period that may be granted by the Panel.