Inclusion Criteria

• Has a histologically confirmed diagnosis of predominant clear cell (conventional) Renal Cell Carcinoma
• Has received at least one prior course of treatment for ccRCC
• Part C only
  • Prior treatment must include at least 1 course of VEGF-directed therapy
• Has CT imaging done within 28 days of day 1 findings consistent with advanced ccRCC, including at least one extra-renal measurable target lesion meeting the criteria of RECIST version 1.1
• Women of childbearing potential and men must agree to use effective contraceptive methods from screening, through the study, and for at least 4 weeks after the last dose of study drug
• Women of childbearing potential must have a negative pregnancy test (serum or urine) on day 1 prior to initiating study treatment
• Must be willing and able to comply with the protocol

Exclusion Criteria

• Has life expectancy of less than 3 months
• Has performance status Grade >2 (Eastern Cooperative Oncology Group [ECOG] criteria)
• Has NYHA Class III or IV heart failure or uncontrolled hypertension (SBP ≥160 mm Hg; DBP ≥100 mm Hg)
• Has previously received X4P-001
• Parts A and B only
  • Has received a prior course of axitinib
  • Has received mTOR inhibitor(s) as their only prior treatment for ccRCC
• Has a prior history or current evidence of intracranial (CNS) metastatic RCC, except for ≤3 lesions treated by CyberKnife or excisional surgery, clinically stable for at least 4 weeks, and without evidence of recurrence on MRI imaging at screening
• Has ongoing acute clinical adverse events NCI CTCAE Grade >1 resulting from prior cancer therapies (except alopecia, TKI-related hand-foot syndrome, or thyroid dysfunction)
• Has had within the past 6 months the occurrence or persistence of one or more of the following medical conditions that could not be controlled with usual medical care (e.g., required emergency care or hospitalization)
  • Hypertension
  • Angina
  • Congestive heart failure
  • Diabetes
  • Seizure disorder
• Has had within the past 6 months the occurrence of one or more of the following events:
  • Myocardial infarction;
  • Cerebrovascular accident;
  • Deep vein thrombosis;
  • Pulmonary embolism;
  • Hemorrhage (CTCAE Grade 3 or 4);
  • Chronic liver disease (meeting criteria for Child-Pugh Class B or C);
  • A second active malignancy (excluding malignancies that were treated curatively and have not recurred within 2 years prior to study treatment;
  • Completely resected basal cell and squamous cell skin cancers;
  • Any malignancy considered to be indolent and that has never required therapy;
  • Completely resected carcinoma in situ of any type), organ transplantation.
• Has had within the 4 weeks prior to initiation of study drug, or is expected to have during the study period, surgery requiring general anesthesia
• Has, at screening, serologic laboratory tests meeting one or more of the following criteria
  • An indeterminate or positive test for antibody to human immunodeficiency virus (HIV-1 or -2)
  • An indeterminate or positive test for antibody to hepatitis C virus (HCV), unless documented to have no detectable viral load on two independent samples
  • A positive test for hepatitis B surface antigen (HBsAg)
• Has, at screening, safety laboratory tests meeting one or more of the following criteria:
  • Hemoglobin <8.0 g/dL;
  • Absolute neutrophil count (ANC) <1,500/μL;
  • Platelets <75,000/μL;
  • Creatinine >2.0x ULN;
  • Serum aspartate transaminase (AST) >2.5x ULN;
  • Serum alanine transaminase (ALT) >2.5x ULN;
  • Total bilirubin >1.5x ULN (unless due to Gilbert's Syndrome).
• Has received other anti-cancer therapy within the following specified intervals prior to Day 1:
  • Tyrosine Kinase Inhibitor (TKI) within 2 weeks;
  • Radiation therapy within 2 weeks;
  • Bevacizumab within 4 weeks;
  • Other chemotherapy (e.g., mitomycin-C, nitrosourea) or immunotherapy (e.g., antibody, cytokine) within 4 weeks;
  • For investigational anti-cancer therapies, the interval will be determined in consultation with the Medical Monitor.
• Has, within 2 weeks prior to day 1, received a medication prohibited based on CYP3A4 interaction.
• Has, within 2 weeks prior to day 1, received systemic corticosteroids exceeding prednisone 10 mg per day or equivalent:
  • For other immunosuppressive agents, the exclusionary dose and duration will be determined in consultation with the Medical Monitor.
• Is, within 2 weeks prior to day 1, nursing.
• Has, at the planned initiation of study drug, an uncontrolled infection.
• Has any other medical or personal condition that, in the opinion of the Investigator, may potentially compromise the safety or compliance of the patient, or may preclude the patient's successful completion of the clinical trial.