Company: NCNA
Filing Date: 2025-06-27
Form Type: 424B5
Source: 0001193125-25-151464
Chunk: 55

Company: NuCana plc
Filing Date: 2025-06-27
Form: 424B5
Chunk 55
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 all or substantially all of our assets. However, any successor to or acquirer of such assets must assume all of our obligations under the indentures or the debt securities, as appropriate. Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions that may afford holders of the debt securities protection in the event we have a change of control or in the event of a highly leveraged transaction (whether or not such transaction results in a change of control), which could adversely affect holders of debt securities. Events of Default Under the Indenture The following are events of default under the indentures with respect to any series of debt securities that we may issue:

| • |     | if we fail to pay interest when due and our failure continues for 90 days and the time for payment has not been 
 extended or deferred;                                                                                           |

| • |     | if we fail to pay the principal, or premium, if any, when due and the time for payment has not been extended or 
 delayed;                                                                                                        |

30

| • |     | if we fail to observe or perform any other covenant set forth in the debt securities of such series or the                                                                                                                                                
 applicable indentures, other than a covenant specifically relating to and for the benefit of holders of another series of debt securities, and our failure continues for 90 days after we receive written notice from the debenture trustee or holders of 
 not less than a majority in aggregate principal amount of the outstanding debt securities of the applicable series; and                                                                                                                                   |

| • |     | if specified events of bankruptcy, insolvency or reorganization occur as to us. |

No event of default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an event of default with respect to any other series of debt securities. The occurrence of an event of default may constitute an event of default under any bank credit agreements we may have in existence from time to time. In addition, the occurrence of certain events of default or an acceleration under the indenture may constitute an event of default under certain of our other indebtedness outstanding from time to time. If an event of default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than a majority in principal amount of the outstanding debt securities of that series may, by a notice in writing to us (and to the debenture trustee if given by the holders), declare to be