Company: PSTV
Filing Date: 2025-08-12
Form Type: S-1
Source: 0001193125-25-178940
Chunk: 7

Company: PLUS THERAPEUTICS, INC.
Filing Date: 2025-08-12
Form: S-1
Chunk 7
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 shares outstanding after this offering will vary depending upon 
 the actual number of shares we sell to Lincoln Park under the Purchase Agreement after the date of this prospectus.                                                                                                                                 |

| Use of proceeds | We will receive no proceeds from the sale of shares of our common stock by Lincoln Park in this offering. We may receive, initially, aggregate gross proceeds of up to the Initial Available Amount and, upon receipt of the full amount thereof,        
 additional aggregate gross proceeds of up to the Additional Available Amount (for total aggregate gross proceeds of up to the Total Available Amount) from sales of shares of our common stock we make to Lincoln Park, if any, pursuant to the Purchase 
 Agreement, assuming that we sell the full amount of our common stock that we have the right, but not the obligation to sell to Lincoln Park under the Purchase Agreement. Through August 8, 2025, we have received approximately $2.8 million under      
 the Purchase Agreement. Any proceeds that we receive from sales of shares of our common stock to Lincoln Park under the Purchase Agreement will be used for working capital and general corporate purposes and to the extent required, for Make-Whole    
 Repayment (as defined in the “Use of Proceeds” section). See “Use of Proceeds.”                                                                                                                                                                          |

| Nasdaq symbol for our common stock | “PSTV” |

| Risk factors | This investment involves a high degree of risk. See “Risk Factors” beginning on page 4 of this prospectus for a discussion of factors you should carefully consider before deciding to invest in our securities. |

Unless otherwise noted, the number of shares of common stock to be outstanding immediately after this offering is based on 99,264,526 shares outstanding as of August 8, 2025 and excludes, as of August 8, 2025:

| • |     | 1,230,272 shares of common stock issuable upon exercise of stock options outstanding under our equity incentive 
 plans, with a weighted-average exercise price of $3.79 per share;                                               |

2

| • |     | 76,025 shares of common stock reserved for future issuance under our 2015 New Employee Incentive Plan; |

| • |     | 20,047,742 shares of common stock reserved for future issuance under our 2020 Stock Incentive Plan; |

| • |     | 398 and 27,792 shares of common stock issuable upon conversion of 1,014 shares of Series B Convertible Preferred 
 Stock and