Inclusion Criteria:

          1. Written informed consent and any locally required authorization (eg, HIPAA) obtained
             from the patient/legal representative prior to performing any protocol-related
             procedures, including screening evaluations.

          2. Metastatic or unresectable cancer that expresses KIT as documented in the patient's
             pathology report.

          3. For patients with GIST, patients will have progressed on at least one prior tyrosine
             kinase inhibitor therapy or be intolerant. If documented to have SDH deficient or
             PDGFRA-D842V GIST, no prior therapy is required for study entry. Other patients with
             KIT positive cancers will have progressed on at least one prior therapy.

          4. Patients must have at least 1 lesion that is measurable using RECIST guidelines.

          5. Females of childbearing potential who are sexually active with a nonsterilized male
             partner must use 2 methods of effective contraception from screening, and must agree
             to continue using such precautions for 60 days after the final dose of study
             medication. Females of childbearing potential are defined as those who are not
             surgically sterile (i.e., bilateral tubal ligation, bilateral oophorectomy, or
             complete hysterectomy) or those who are postmenopausal (defined as 12 months with no
             menses without an alternative medical cause).

          6. Nonsterilized males who are sexually active with a female partner of childbearing
             potential must, with their partner, use 2 acceptable methods of effective
             contraception from Day 1 through 60 days after receipt of the final dose of study
             medication.

          7. ECOG status of 0 or 1.

          8. Adequate organ function as defined below:

               -  Hemoglobin ≥ 9 g/dL. This criterion must be met without transfusion.

               -  Absolute neutrophil count ≥ 1500/mm3

               -  Platelet count ≥ 100,000/mm3

               -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 5 × upper
                  limit of normal (ULN) for cases involving liver metastasis and ≤ 2.5 ×ULN for all
                  other cases

               -  Bilirubin ≤ 1.5 × ULN except for cases of documented or suspected Gilbert's
                  disease, in which bilirubin must be ≤ 5 × ULN

               -  Serum creatinine ≤ 1.5 g/dL

        Exclusion Criteria:

          1. Receipt of anticancer therapy:

               -  Within 3 weeks prior to the first dose of CDX-0158 of any biologic treatment or
                  IV chemotherapy.

               -  Within 2 weeks prior to the first dose of CDX-0158 of any oral therapy or 5.5
                  half lives whichever is longer or following palliative radiation therapy.

             Concurrent use of hormones for non-cancer related conditions (e.g., insulin for
             diabetes and hormone replacement therapy) is acceptable.

          2. Requirement for chronic immunosuppressive medication including systemic
             corticosteroids above the physiologic dose (30 mg/day hydrocortisone or the
             equivalent).

          3. Known allergy or past administration reaction including infusion related reaction
             (IRRs), anaphylactic, or anaphylactoid reactions to any component of the CDX-0158
             formulation.

          4. History of clinically significant allergic reactions or atopic disease that may pose
             an increased risk of severe CDX-0158 IRRs.

          5. Symptomatic or untreated central nervous system metastases requiring concurrent
             treatment, including but not limited to surgery, radiation, and/or corticosteroids; if
             treated, patient must be asymptomatic for 3 months prior to study entry.

          6. Other invasive malignancy within 2 years prior to enrollment (localized prostate
             cancer, cervical carcinoma in situ, non-melanoma skin cancer, or ductal carcinoma in
             situ of the breast that has/have been surgically cured would not be exclusionary).

          7. Unresolved toxicities from prior anticancer therapy, defined as having not resolved to
             NCI CTCAE v 4.03 < Grade 2 or normalized to baseline, or to levels dictated in the
             inclusion/exclusion criteria, with the exception of alopecia.

          8. Major surgical procedure (as defined by the investigator) within 30 days prior to
             Study Day 1 or incomplete recovery from any prior surgery.

          9. Pregnancy or breast feeding

         10. Uncontrolled intercurrent illness that would limit compliance with study requirements
             or compromise the patient such as ongoing or active infection, symptomatic congestive
             heart failure, hypertension requiring adjustment of medication, idiopathic and
             symptomatic hypotension, unstable angina pectoris, clinically significant cardiac
             arrhythmia including uncontrolled atrial fibrillation, active peptic ulcer disease or
             gastritis with ongoing blood loss, or psychiatric illness/social situations that would
             limit compliance or compromise the ability of the patient to give written informed
             consent.

         11. Any condition that, in the opinion of the investigator, would interfere with
             evaluation of the study medication or interpretation of patient safety or study
             results.

         12. Concurrent enrollment in another clinical study, unless it is an observational
             (non-interventional) study.

         13. Patients with a left ventricular cardiac ejection fraction < 50% as assessed by an
             echocardiogram or MUGA scan or prolonged QTc interval of Grade 2 or higher or history
             of prolonged QTc interval from other drugs.