This clinical trial will evaluate raludotatug deruxtecan (R-DXd; DS-6000a) in participants with advanced renal cell carcinoma (RCC) and ovarian cancer (OVC). The main goals of this study will be to investigate the recommended dose of R-DXd that can be given safely to participants, assess the adverse events of R-DXd, and evaluate the effectiveness of R-DXd.

R-DXd is an antibody drug conjugate that specifically binds to CDH6 on the cell surface of target cells, which leads to the internalization of R-DXd into the cells. MAAA-1181a that is released from R-DXd in the target cells inhibits cell replication and induces cell apoptosis.

This study will evaluate R-DXd given as a single agent once every 21 days. The dose escalation phase will enroll participants with OVC and RCC, and is designed to assess the safety and tolerability of R-DXd and to determine the maximum tolerated dose (MTD)/recommended dose for expansion (RDE). Following the selection of the RDE, the dose expansion phase will be initiated to evaluate clinical activity of R-DXd.

Inclusion Criteria:

• Written informed consent
• At least 18 years of age
• Eastern Cooperative Oncology Group Performance Status score of 0 or 1
• Availability of archived tumor tissue samples
• Has a left ventricular ejection fraction (LVEF) ≥50% by either an echocardiogram (ECHO) or multigated acquisition scan (MUGA) within 28 days before start of study treatment
• Has adequate organ function within 7 days before the start of study treatment
• Has an adequate treatment washout period prior to start of study treatment
• Male participants with female partners of childbearing potential and female participants of child-bearing potential must agree to use a highly effective form of contraception or avoid intercourse during and upon completion of the study and for at least 4 months (for males) and for at least 7 months (for females) after the last dose of study drug.

Exclusion Criteria:

• Has had prior treatment with other CDH6-targeted agents
• Has had prior treatment with an ADC that consists of an exatecan derivative that is a topoisomerase I inhibitor (e.g., trastuzumab deruxtecan, datopotamab deruxtecan, ifinatamab deruxtecan, DS-3939)
• Has history or current presence of CNS metastases except for participants who have completed radiotherapy or surgery ≥2 weeks before the start of study treatment and have no evidence of disease progression in the CNS and no requirement for chronic corticosteroid therapy within 2 weeks before the start of study treatment
• Has multiple primary malignancies, except adequately resected non-melanoma skin cancer, curatively treated in situ disease, or other solid tumors curatively treated, with no evidence of disease for ≥3 years)
• Has a history of myocardial infarction or unstable angina within 6 months before start of study treatment
• Has a medical history of symptomatic congestive heart failure (New York Heart Association classes II-IV) or a cardiac arrhythmia requiring treatment
• Lung-specific intercurrent clinically significant illnesses
• Has an uncontrolled infection requiring systemic therapy

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.