A Study of Mipasetamab Uzoptirine (ADCT-601) in Participants With Solid Tumors

Prior treatment

• Symptomatic central nervous system (CNS) metastases or evidence of leptomeningeal disease (brain magnetic resonance imaging [MRI] or previously documented cerebrospinal fluid [CSF] cytology). Previously treated asymptomatic CNS metastases are permitted provided that the last treatment (systemic anticancer therapy and/or local radiotherapy) was completed ≥4 weeks prior to Day 1 except usage of low dose of steroids on a taper (i.e., up to 10 mg prednisone or equivalent on Day 1 and consecutive days is permissible if being tapered down). Participants with discrete dural metastases are eligible.
• Use of any other experimental medication within 14 days prior to start of study drug (C1D1).

Other illness

• History of recent infection requiring intravenous (IV) antibiotics, IV antiviral, or IV antifungal treatment within 4 weeks of Cycle 1 Day 1 (C1D1).
• Active diarrhea Common Terminology Criteria for Adverse Events (CTCAE) Grade 2 or a medical condition associated with chronic diarrhea (such as irritable bowel syndrome, inflammatory bowel disease).

Other

• Clinically significant third space fluid accumulation (i.e., ascites requiring drainage or any serosal effusion that is either requiring drainage or associated with shortness of breath).

• Male or female participant aged 18 years or older.
• Pathologic diagnosis of solid tumor malignancy that is locally advanced or metastatic at time of screening:
  • Part 1:
  • Combination therapy arms: Selected sarcoma indications from the following 2 separate categories.
  • Soft tissue sarcoma: leiomyosarcoma, liposarcoma, undifferentiated pleomorphic sarcoma (UPS; covering malignant fibrous histiocytoma) and synovial sarcoma.
  • Bone sarcoma: Ewing's sarcoma (including extraskeletal), osteosarcoma, and chondrosarcoma.
  • Monotherapy arms:
  • Sarcoma indications (including those listed for combination therapy arms) regardless of AXL gene amplification status.
  • NSCLC regardless of AXL gene amplification status.
  • Solid tumors (lymphomas participants are excluded) with known AXL gene amplification.
  • Part 2:
  • Combination therapy arms: Sarcoma indications and PAAD.
  • Monotherapy arms: PAAD, NSCLC and solid tumors with AXL expression.
• Participants who are refractory to or intolerant to available standard therapy(ies) known to provide clinical benefit for their condition per Investigator judgment.
• Participants with measurable disease as determined by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 - 1.
• PAAD only: Royal Marsden Hospital Prognostic Score 0 - 1.