First-in-Human Study of DS-3939a in Participants With Advanced Solid Tumors

Eligibility Criteria

• * Sign and date the main Informed Consent Form (ICF).
• * Has a left ventricular ejection fraction ≥50% by either an echocardiogram or multigated acquisition within 28 days of enrollment.
• * Has adequate organ function.
• * Measurable disease based on RECIST V1.1.
• * Eastern Cooperative Oncology Group performance status score of 0 or 1.
• * Has a histologically or cytologically documented locally advanced, metastatic, or unresectable urothelial, non-small cell lung, breast, ovarian, or biliary tract cancers, or pancreatic ductal adenocarcinoma, regardless of any molecular subtypes.
• * Has a histologically or cytologically documented locally advanced, metastatic, or unresectable cancer meeting the protocol criteria and documented radiographic disease progression during or after the most recent anticancer therapy.
• * Is able to provide either of the following baseline tumor samples:
• * Fresh core needle biopsy samples obtained during the Screening Period, or
• * Alternative FFPE tumor tissue samples obtained by biopsy or surgery performed after the completion date of the most recent anticancer therapy regimen and within 6 months before signing the ICF
• * Has had prior treatment targeting mucin 1 (MUC1) or TA-MUC1.
• * Has spinal cord compression or history of/clinically active central nervous system metastases.
• * Has multiple primary malignancies, except adequately resected nonmelanoma 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 noninfectious interstitial lung disease (ILD)/pneumonitis (including suspected one), has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at Screening.
• * Has active human immunodeficiency virus (HIV) infection as determined by plasma HIV ribonucleic acid viral load and cluster of differentiation 4 count.
• * Has evidence of active hepatitis B virus or hepatitis C virus infection.
• * Any of the following within the past 6 months: cerebrovascular accident, transient ischemic attack, or other arterial thromboembolic event.
• * Has an active, known, or suspected autoimmune disease.
• * Current participation in other therapeutic investigational procedures, except for participation in Long Term Follow-Up without any investigational treatment.