Ph 2/3 Study in Subjects With MPM w/Low ASS 1 Expression to Assess ADI-PEG 20 With Pemetrexed and Cisplatin

Inclusion Criteria:

1. Histologically proven advanced MPM of biphasic or sarcomatoid histology. Biphasic MPM
is defined using the World Health Organization's international histological
classification of tumors as containing an epithelial and a sarcomatoid component with
each component comprising at least 10% of the tumor

2. Naïve to prior chemotherapy or immunotherapy (i.e., this is a first-line systemic
therapy study).

3. MPM tumor sample for determination of ASS1 status. ASS1-deficiency is not required for
study entry at study start, but tumor sample for ASS1 status is required. This study
will employ an adaptive biomarker-driven design with an interim analysis to be
conducted at the end of the phase 2 portion. The interim analysis will evaluate the
treatment effect of ADI PEG 20 in combination with pemetrexed and cisplatin on overall
survival (OS) in the overall population (biphasic and sarcomatoid histology patients)
and pre-defined subpopulation of biomarker-positive patients (ASS1-deficient
subpopulation). Thus ASS1 deficiency may be required for the phase 3 portion of the
study, pending the interim analysis. ASS1-deficiency, demonstrated on tissue specimen
(cytospin samples are not acceptable), will be defined in the laboratory manual. If
archived tissue is not sufficient or not available, then tissue must be obtained by
biopsy.

4. Measurable disease as assessed by modified RECIST for MPM for thoracic disease
(Appendix A) and RECIST 1.1 for extra-thoracic disease (Appendix B).

5. ECOG performance status of 0 - 1 (Appendix C).

6. Predicted life expectancy of at least 12 weeks.

Exclusion Criteria:

1. Radiotherapy (except for palliative reasons) the previous two weeks before.

2. Ongoing toxic manifestations of previous treatments.

3. Symptomatic brain or spinal cord metastases (patients must be stable for > 1 month
post radiotherapy or surgery).

4. Major thoracic or abdominal surgery from which the patient has not yet recovered.

5. Serious infection requiring treatment with intravenous antibiotics at the time of
study entrance, or an infection requiring intravenous therapy within 7 days prior.

6. Known to be serologically positive for human immunodeficiency virus (HIV). Testing to
determine possible infection status is not required.