Company: NCNA
Filing Date: 2025-06-27
Form Type: 424B5
Source: 0001193125-25-151464
Chunk: 65

Company: NuCana plc
Filing Date: 2025-06-27
Form: 424B5
Chunk 65
---
 of the governing unit agreement that differ from those described below; and |

| • |     | any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities 
 comprising the units.                                                                                        |

The provisions described in this section, as well as those set forth in any prospectus supplement or as described under “Description of Share Capital,” “Description of American Depositary Shares,” “Description of Debt Securities,” “Description of Warrants,” and “Description of Rights” will apply to each unit, as applicable, and to any ordinary shares represented by ADSs, debt security, warrant or right included in each unit, as applicable. Unit Agent The name and address of the unit agent, if any, for any units we offer will be set forth in the applicable prospectus supplement. Issuance in Series We may issue units in such amounts and in such numerous distinct series as we determine. Enforceability of Rights by Holders of Units Each unit agent will act solely as our agent under the applicable unit agreement and will not assume any obligation or relationship of agency or trust with any holder of any unit. A single bank or trust company may act 38

as a unit agent for more than one series of units. A unit agent will have no duty or responsibility in case of any default by us under the applicable unit agreement or unit, including any duty or
responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a unit may, without the consent of the related unit agent or the holder of any other unit, enforce by appropriate legal action its rights as
holder under any security included in the unit.

39

DESCRIPTION OF AMERICAN DEPOSITARY SHARES

American Depositary Shares

Citibank has
agreed to act as the depositary for the ADSs. Citibank’s depositary offices are located at 388 Greenwich Street, New York, New York 10013. ADSs represent ownership interests in securities that are on deposit with the depositary. ADSs may
be represented by certificates that are commonly known as American Depositary Receipts, or ADRs. The depositary typically appoints a custodian to safekeep the securities on deposit. In this case, the custodian is Citibank, N.A., London Branch.

We have appointed Citibank as depositary pursuant to a an amended and restated deposit agreement dated May 7, 2025, or the deposit
agreement. A copy of the