This research is being conducted to determine the biodistribution of radiolabeled amatuximab in tumor and non-tumor tissues in subjects with mesothelin over expressing cancer including mesothelioma, pancreatic, ovarian or non small cell lung cancer.

The primary objective is to determine the biodistribution of radiolabeled amatuximab in tumor and nontumor tissues in subjects with mesothelin over-expressing cancers including mesothelioma, pancreatic, ovarian, and non small cell lung cancer. This is a single-center, single-dose, open-label, pilot study of amatuximab in approximately 20 subjects with mesothelin expressing tumors. 111Indium-radiolabeled amatuximab (5 mCi) will be administered. Serial SPECT imaging (at 3 specific time points up to 196 hours after cold infusion) will be performed to determine binding to tumor and nontumor tissue. Subjects will be observed closely for safety and possible development of anti-amatuximab antibodies. Pharmacokinetics of radiolabeled antibody will be determined with imaging over time.

Inclusion Criteria:

• Female and Male subjects > or = 18 years of age
• Histologically confirmed mesothelin-expressing cancer
• Measurable disease that has progressed through prior therapy and that includes a non-hepatic lesion for imaging that is > or = 1.5cm, as defined by RECIST v1.1 and disease location, at discretion of the physician, or evaluable by clinical symptoms supported by biomarker, radiological or pathological studies conducted within 4 weeks prior to study entry

Exclusion Criteria:

• Known allergy or hypersensitivity to monoclonal antibodies
• Known to develop HACA
• Prior treatment with amatuximab
• Prior treatment with SS1 (dsFv)PE38 (ss1P)
• Prior treatment with another test article within previous 30 days
• Known brain metastasis
• Known prosthetic devices that would prohibit imaging ow lesion of interest due to radiographic artifact
• Chemotherapy, biological therapy, radiation therapy or immunotherapy within 3 weeks prior to dosing with amatuximab