NCNA furnishes Exhibit 99.1 on NUC-7738 and PD-1 synergy at ESMO

Rhea-AI Filing Summary

NuCana plc furnished a Form 6-K announcing it issued a press release about new research presented at ESMO 2025. The presentation covers a model system investigating the synergistic effects of NUC-7738 and PD-1 inhibition in primary organoids derived from patients with renal cell carcinoma.

The press release is attached as Exhibit 99.1 and is incorporated by reference. The information in Exhibit 99.1 is being furnished and not deemed filed under the Exchange Act.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of October 2025

(Commission File No. 001-38215)

NUCANA PLC

(Translation of registrant’s name into English)

3 Lochside Way

Edinburgh EH12 9DT

United Kingdom

(Address of registrant’s principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F ☒    Form 40-F ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (1): ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (7): ☐

Other Events

On October 18, 2025, NuCana plc (the “Company”) issued a press release announcing the presentation of data on a new model system investigating the synergistic effects of NUC-7738 and PD-1 inhibition in primary organoids derived from patients with renal cell carcinoma at the European Society for Medical Oncology (ESMO) Congress 2025. The press release is attached as Exhibit 99.1 hereto and is incorporated by reference herein.

The information in the attached Exhibit 99.1 is being furnished and shall not be deemed “filed” for the purposes of Section 18 of the Securities 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.

Exhibits
99.1		Press Release, dated October 18, 2025

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/ Ian Webster
Name:		Ian Webster
Title:		Interim Chief Financial Officer (Principal Financial and Accounting Officer)

Date: October 20, 2025

FAQ

What did NCNA announce in this Form 6-K?

NuCana reported a press release about data presented at ESMO 2025 on a model system studying synergistic effects of NUC-7738 and PD-1 inhibition in renal cell carcinoma organoids.

Where and when was the research presented by NCNA?

At the European Society for Medical Oncology (ESMO) Congress 2025; the press release is dated October 18, 2025.

What therapy combination is highlighted by NCNA?

NUC-7738 in combination with PD-1 inhibition, evaluated in primary organoids from renal cell carcinoma patients.

How is the press release included with the 6-K for NCNA?

It is attached as Exhibit 99.1 and incorporated by reference.

Is the Exhibit 99.1 information considered filed for NCNA?

No. It is being furnished and is not deemed filed under Section 18 of the Exchange Act.

Who signed the NCNA Form 6-K and in what capacity?

Ian Webster, Interim Chief Financial Officer (Principal Financial and Accounting Officer).

What is the subject cancer type in NCNA’s update?

Renal cell carcinoma, studied via primary patient-derived organoids.