Inclusion Criteria

- INCLUSION CRITERIA:

Subjects must meet all of the following criteria to be eligible to participate in the
study:

Subjects must have histologically confirmed epithelial or biphasic pleural mesothelioma
not amenable to potentially curative surgical resection. However, patients with biphasic
tumors that have a predominantly sarcomatoid component will be excluded.

Measurable disease

Subjects must be greater than or equal to 18 years old

Karnofsky Performance Status (KPS) of greater than or equal to 70

Life expectancy of greater than 3 months, as assessed by the principal investigator.

Adequate organ function with:Hepatic function: serum transaminases (either ALT or AST) or
bilirubin, less than or equal to Grade 1, unless due to cancer or Gilbert's disease; less
than or equal to Grade 2, if due to cancer

Renal function: serum creatinine clearance greater than or equal to 60mL/min as estimated
by Cockroft-Gault formula.

Bone marrow function: ANC of at least 1,500/mm (3), Platelet count at least 100,000/mm (3)

Pulmonary Function: FEV (1) greater than or equal to 50 percent of predicted value
(post-pleural drainage and bronchodilation if these are indicated)

Must be able to understand and sign informed consent

Female and male subjects agree to use an approved method of contraception during the study

EXCLUSION CRITERIA:

Subjects must not be pregnant or breast feeding

Prior radiotherapy (except palliative extra-thoracic localized radiotherapy) or biologic
therapy for malignant pleural mesothelioma within 4 weeks

Prior systemic chemotherapy for malignant pleural mesothelioma

Documented and ongoing central nervous system involvement with their malignant disease
(history of CNS involvement is not an exclusion criterion but the CNS metastases should
have been adequately treated (radiation or surgical resection) and subjects are free from
symptoms for 3 months off steroids).

Clinically significant heart disease (New York Heart Association Class III or IV)

Active bacterial or fungal infection.

Baseline coagulopathy greater than or equal to Grade 3 unless due to anticoagulant therapy

Surgery or pleurodesis within 2 weeks

HIV positive serology (due to increased risk of severe infection and unknown interaction
of SS1(dsFv)PE38 with antiretroviral drugs)

Hepatitis B surface antigen positivity

Subjects with other (non-mesothelioma) cancers who meet eligibility criteria and have had
less than 5 years of disease-free survival will be considered on a case-by-case basis

Uncontrolled, symptomatic, intercurrent illness including but not limited to: infections
requiring systemic antibiotics, unstable angina pectoris, cardiac arrhythmia, psychiatric
illness, or social situations that would limit compliance with study requirements.