Inclusion Criteria:

          -  Males and females ≥ 18 years of age

          -  Histologically or cytologically confirmed advanced solid tumor malignancy, refractory
             or relapsed from prior therapy, or for whom no alternative therapy is available

          -  At least 4 weeks beyond the last chemotherapy (or ≥ 5 half-lives for targeted agents,
             whichever is shorter), radiotherapy, major surgery or experimental treatment and
             recovered from all acute toxicities (≤ Grade 1)

          -  Archival tumor sample available, or be willing to undergo a fresh tumor biopsy, prior
             to study

          -  At least one measurable disease site that meets target lesion requirements

          -  Adequate performance status: Eastern Cooperative Oncology Group (ECOG) ≤ 2

          -  Life expectancy of ≥ 3 months

          -  Adequate hematologic parameters without ongoing transfusional support:

          -  Negative serum pregnancy test

          -  Ability to provide written informed consent

        Exclusion Criteria:

          -  Previous radioimmunotherapy. Previous antibody-based therapy is allowed as long as ≥
             28 days has elapsed from last dose to study treatment.

          -  Prior radiation to > 30% of the red marrow or to maximal tolerable level for any organ

          -  Serious cardiac condition within the last 6 months

          -  Concomitant medication(s) that may cause QTc prolongation or induce Torsades de
             Pointes, with the exception of antimicrobials that are considered to be essential for
             care of the patient

          -  History of retinal degenerative disease, history of uveitis, history of retinal vein
             occlusion (RVO), or any eye condition that would be considered a risk factor for RVO
             or has medically relevant abnormalities identified on screening ophthalmologic
             examination

          -  Active central nervous system (CNS) malignant disease in subjects with a history of
             CNS malignancy. Subjects with stable, prior, or currently treated brain metastases are
             allowed.

          -  Known positive for human immunodeficiency virus (HIV), hepatitis B virus surface
             antigen (HBsAg) or hepatitis C virus (HCV)

          -  Known autoimmune disease

          -  Active infection requiring intravenous (IV) antibiotic usage within the last week
             prior to the dosimetry portion of the study

          -  Corticosteroid use within 2 weeks of study treatment

          -  Any other medical intervention or other condition which, in the opinion of the
             Principal Investigator, could compromise adherence with study requirements or confound
             the interpretation of study results

          -  Pregnant or breast-feeding