Company: NCNA
Filing Date: 2025-06-27
Form Type: 424B5
Source: 0001193125-25-151464
Chunk: 63

Company: NuCana plc
Filing Date: 2025-06-27
Form: 424B5
Chunk 63
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 terms described below will be deemed to have been superseded by that prospectus supplement. We encourage you to read the applicable rights agreement and rights certificate for additional information before you decide whether to purchase any of our rights. We will provide in a prospectus supplement the following terms of the rights being issued:

| • |     | the date of determining the shareholders entitled to the rights distribution; |

| • |     | the aggregate number of ordinary shares represented by ADSs or other securities purchasable upon exercise of the 
 rights;                                                                                                          |

| • |     | the exercise price; |

| • |     | the aggregate number of rights issued; |

| • |     | whether the rights are transferrable and the date, if any, on and after which the rights may be separately 
 transferred;                                                                                               |

| • |     | the date on which the right to exercise the rights will commence, and the date on which the right to exercise the 
 rights will expire;                                                                                               |

| • |     | the method by which holders of rights will be entitled to exercise; |

| • |     | the conditions to the completion of the offering, if any; |

| • |     | the withdrawal, termination and cancellation rights, if any; |

| • |     | whether there are any backstop or standby purchaser or purchasers and the terms of their commitment, if any; |

| • |     | whether shareholders are entitled to oversubscription rights, if any; |

| • |     | any applicable material U.S. federal income tax considerations and any applicable material U.K. tax 
 considerations; and                                                                                 |

| • |     | any other terms of the rights, including terms, procedures and limitations relating to the distribution, exchange 
 and exercise of the rights, as applicable.                                                                        |

Each right will entitle the holder of rights to purchase for cash the principal amount of ordinary shares represented by ADSs or other securities at the exercise price provided in the applicable prospectus supplement. Rights may be exercised at any time up to the close of business on the expiration date for the rights provided in the applicable prospectus supplement. Holders may exercise rights as described in the applicable prospectus supplement. Upon receipt of payment and the rights certificate properly completed and duly executed at the corporate trust office of the rights agent or 36

any other office indicated in the prospectus supplement, we will, as soon as practicable, forward the ordinary shares represented by ADS or other securities, as applicable, purchasable upon
exercise