This open-label, multicenter, rollover study will provide continued treatment for participants deriving benefit from different therapies received in studies sponsored by Daiichi Sankyo, Inc. (DS) or DS/Astra Zeneca (AZ)-sponsored study (eg. DS8201-A-J101, DS8201-A-U201, DS8201-A-U204, DS8201-A-U207, DS8201-A-U303).

This Master Rollover Study includes sub-protocols with different study drugs. This Master Rollover Protocol describes core study elements that are applicable to all study drugs that will be provided under the Rollover Study.

Inclusion Criteria:

• Signed informed consent form, prior to the start of any study-specific qualification procedures and willing to comply with all study requirements.
• Currently enrolled in a DS or DS/AZ-sponsored parent study that has met EOS definition.
• No evidence of progressive disease and determined to have investigator-assessed clinical benefit from continued treatment with a DS or DS/AZ alliance study drug(s).

Exclusion Criteria:

• Participants with any unresolved/ongoing AE(s) that meets the study drug discontinuation criteria
• Participant who has been off T-DXd therapy for >18 weeks (126 days) between the last dose from the parent study and the initiation of study drug administration on this study

De-identified individual participant data (IPD) on completed studies and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https://vivli.org/ourmember/daiichi-sankyo/

Completed studies that has reached a global end or completion with all data set collected and analyzed, and for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.

Formal request from qualified scientific and medical researchers on IPD and clinical study documents on completed clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.