This is the first-in-human (Phase I) study of AMG 172, an antibody drug conjugate (ADC), in subjects with kidney cancer [Clear Cell Renal Cell Carcinoma (ccRCC)] who have relapsed or who have refractory disease following at least two prior therapies. The purpose of the study is to evaluate safety and pharmacokinetics (PK) of AMG 172, and also evaluate the objective response rate in patients with ccRCC receiving AMG 172. The study will be conducted in two Parts: Part 1 will explore doses of AMG 172 given every two weeks and every three weeks to determine the safety, tolerability and pharmacokinetics to establish a maximum tolerated dose (MTD), and Part 2 (dose expansion) will examine safety, tolerability, PK and overall response rate in subjects treated at the MTD established in Part 1 for either every two week or every three week dosing.

This First in- human study of AMG 172 will be conducted in two parts: Part 1 (dose exploration) and Part 2 (dose expansion). Part 1 of the study is aimed at evaluating the safety, tolerability and PK of AMG 172 given every two weeks and every three weeks in subjects with relapsed / refractory cc RCC, and Part 2 is aimed at evaluating safety, tolerability, PK and response rate in subjects treated at the MTD established in Part 1 for either every two week or every three week dosing. Up to 48 subjects may be enrolled in Part 1, and up to 30 subjects may be enrolled in Part 2. The dose of AMG 172 utilized in Part 2 will be dependent upon data obtained in Part 1 of the study.

Inclusion Criteria:

• Subjects must have a pathologically documented, definitively diagnosed, clear cell RCC that is relapsed/refractory following at least two lines of systemic therapy (one of which must be a tyrosine kinase), or the subject refuses standard therapy

• Measurable disease per RECIST 1.1 criteria. Subjects with non-measurable, but evaluable disease are also eligible for Part 1 of the study.

• Eastern Cooperative Oncology Group (ECOG) Performance Status of ≤ 1

• Willing to provide tumor samples and / or slides

• Hematological function, as follows:

  1. Absolute neutrophil count (ANC) ≥ 1.5 x 10^9/L;
  2. Platelet count ≥ 100 x 10^9/L;
  3. Hemoglobin > 9 g/dL

• Prothrombin time (PT) or partial thromboplastin time (PTT) < 1.5 x institutional upper limit of normal (IULN)

• Hepatic function, as follows:

  1. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) < 3 x ULN;
  2. Total bilirubin < 1.5 x ULN (< 3.0 x ULN for subjects with documented Gilbert's Disease or for whom the indirect bilirubin level suggests an extrahepatic source of elevation);
  3. Alkaline phosphatase < 2 x ULN (< 5 x ULN in subjects whom the PI and sponsor agree that clinical data suggest extrahepatic source of elevation)

• Other inclusion criteria may apply

Exclusion Criteria:

• Known primary central nervous system (CNS) tumors or brain metastases
• History of bleeding diathesis
• Myocardial infarction within 6 months of study day 1, symptomatic congestive heart failure (New York Heart Association > class II), unstable angina, or unstable cardiac arrhythmia requiring medication, or uncontrolled hypertension in the opinion of the investigator
• Clinically significant ECG changes which obscure the ability to assess the PR, QT, and QRS interval; congenital long QT syndrome
• A baseline ECG QTcF > 470 msec
• Known positive test for human immunodeficiency virus (HIV)
• Known acute or chronic hepatitis B or hepatitis C infection as determined by serologic tests
• Other exclusion criteria may apply