Company: NCNA
Filing Date: 2025-06-05
Form Type: 6-K
Source: 0001193125-25-135874
Chunk: 1

Company: NuCana plc
Filing Date: 2025-06-05
Form: 6-K
Chunk 1
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 may not receive voting materials in time to enable them to return voting instructions to the Depositary in a timely manner. The notice materials to be mailed by the Depositary to ADS holders will contain a link to the Company’s website where ADS holders can view and download the AGM notice distributed by the Company to its ordinary shareholders (which contains explanatory notes for the resolutions being voted on at the AGM) and the UK Annual Report. The information contained in Exhibits 99.1 and 99.2 shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, unless expressly set forth by specific reference in such a filing. Exhibits

| Exhibit |     | Description                      |
| 99.1    |     | Notice of Annual General Meeting |
| 99.2    |     | 2024 UK Annual Report            |

SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

| NuCana plc |     |                         |
| By:        |     | /s/ Hugh S Griffith     |
| Name:      |     | Hugh S. Griffith        |
| Title:     |     | Chief Executive Officer |

Date: June 5, 2025