Safety and Efficacy Study of ARQ 501 in Adult Patients With Leiomyosarcoma

Inclusion Criteria:

* Able to provide signed and dated informed consent prior to study-specific screening procedures.
* Histologically or cytologically confirmed leiomyosarcoma that is persistent, recurrent or metastatic.
* Measurable disease as defined by RECIST.
* Karnofsky performance status \>= 70%
* Male or female patients of child-producing potential must agree to use contraception or avoidance of pregnancy measures during the study and for 30 days after the last infusion of ARQ 501.
* Hemoglobin (Hgb) \>= 10 g/dL.
* Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L (\>= 1,500/mm3).
* Platelet count \>= 100 x 10\^9/L (\>= 100,000/mm3).
* Total bilirubin less than or equal to 1.5 x upper limit of normal (ULN) or less than or equal to 3.0 x ULN with metastatic liver disease.
* Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) less than or equal to 2.5 x ULN less than or equal to 5.0 ULN with metastatic liver disease.
* Creatinine less than or equal to 1.5 x ULN.

Exclusion Criteria:

* Received three or more prior anticancer chemotherapy regimens.
* Have active, uncontrolled systemic infection considered opportunistic, life threatening or clinically significant at the time of treatment.
* Have received anticancer chemotherapy, immunotherapy, radiotherapy, surgery or investigational agents within four weeks of first infusion.
* Have symptomatic or untreated central nervous system (CNS) involvement.
* Are pregnant or breastfeeding.
* Previous exposure to ARQ 501.