Company: NCNA
Filing Date: 2025-11-13
Form Type: 6-K
Source: 0001193125-25-280224
Chunk: 1

Company: NuCana plc
Filing Date: 2025-11-13
Form: 6-K
Chunk 1
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 Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, nor shall it be deemed incorporated by reference in any filing made by the Company under the Securities Act of 1933, as amended, or the Exchange Act, except as otherwise set forth herein or as shall be expressly set forth by specific reference in such a filing. Board of Directors Matters Effective October 21, 2025, Bali Muralidhar, M.D., Ph.D. resigned from his role as a member of the Board of Directors (the “Board”) of the Company and all committees of the Board. Dr. Muralidhar’s resignation was not the result of any dispute with the Company or the Board on any matter relating to the operations, policies or practices of the Company. Exhibits

| Exhibit 
 99.1    
 99.2    |     | Description                                                                                                                                           
 Unaudited Condensed Consolidated Financial Statements as of September 30, 2025 and for the Three and Nine Months Ended September 30, 2025 and 2024    
 Management’s Discussion and Analysis of Financial Condition and Results of Operations for the Three and Nine Months Ended September 30, 2025 and 2024 |
|:--------|:----|:------------------------------------------------------------------------------------------------------------------------------------------------------|
| 99.3    |     | Press Release Dated November 13, 2025                                                                                                                 |
| 104     |     | Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)                                                              |

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, thereto duly authorized.

| NuCana plc |     |                                                                              |
| By:        |     | /s/ Ian Webster                                                              |
| Name:      |     | Ian Webster                                                                  |
| Title:     |     | Interim Chief Financial Officer (Principal Financial and Accounting Officer) |

Date: November 13, 2025