Company: HCWB
Filing Date: 2025-04-16
Form Type: 424B3
Source: 0001193125-25-082835
Chunk: 6

Company: HCW Biologics Inc.
Filing Date: 2025-04-16
Form: 424B3
Chunk 6
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15agonist receptor) through pivotal trials. This blockbuster immunotherapeutic product for cancer was sold to ImmunityBio, Inc. in 2017 in a $1.0 billion acquisition. Anktiva ®was approved by the U.S. Food and Drug Administration (“FDA”) for a bladder cancer indication in 2024. Summary of Risk Factors Investing in our securities involves a high degree of risk. You should review carefully all the information contained in this prospectus before making an investment in our securities. The following list summarizes some, but not all, of these risks. Please read the information in the section titled “Risk Factors” for a more thorough description of these and other risks.

| • |     | The issuance and sale of shares of Common Stock under the ELOC Purchase Agreement and the Purchase Warrant will 
 likely cause substantial dilution and the price of our Common Stock to decline.                                 |

| • |     | We may not have access to the full amount available under the ELOC Purchase Agreement. |

| • |     | Square Gate will pay less under the terms of the ELOC Purchase Agreement than the then-prevailing market price 
 for our Common Stock, which could cause the price of our Common Stock to decline.                              |

| • |     | It is not possible to predict the actual number of shares we will sell under the ELOC Purchase Agreement or the 
 Purchase Warrant to the selling stockholders, or the actual gross proceeds resulting from those sales.          |

| • |     | Investors who buy shares in this offering at different times will likely pay different prices. |

| • |     | Our need for future financing may result in the issuance of additional securities, which will cause investors to 
 experience dilution.                                                                                             |

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| • |     | We have incurred significant financial losses since our inception, and we expect to incur losses for the              
 foreseeable future. We have no products approved for commercial sale and may never achieve or maintain profitability. |

| • |     | The Company implemented remediation of material weaknesses identified in previous reporting periods. If we fail                                                                                                                                         
 to maintain an effective system of disclosure controls and internal control over financial reporting, our ability to produce timely and accurate financial statements or comply with applicable laws and regulations could be impaired, which may cause 
 investors to lose confidence in our reported financial information and may lead to a decline in the market price of our Common Stock.                                                                                                                   |

| • |     | We and our Chief Executive Officer were involved in legal proceedings with Altor BioScience