Evaluation of Safety, Tolerability, PK & PD of Intravenous VX15/2503 in Patients With Advanced Solid Tumors

Main Inclusion Criteria:

* Patients 18 yrs or older with confirmed histological or cytological advanced solid tumors, relapsed or refractory to standard treatment for which no curative therapy is available; patients must demonstrate progressive disease prior to entry
* Has measurable disease as defined by RECIST1.1
* Life expectancy of at least 3 months (per investigator assessment)
* ECOG performance status of 0-2
* Adequate bone marrow, renal and liver function
* Recovered from any significant prior toxicity of previous anti-neoplastic therapy
* For patients of reproductive potential, is willing to use a medically acceptable form of contraception throughout the study period and for at least 4 weeks after the last dose of VX15/2503
* Expansion cohort - patients in this cohort must have one of the following characteristics:
* A diagnosis of a pancreatic neuroendocrine tumor OR
* A diagnosis of a soft tissue sarcoma OR
* A diagnosis of a bone metastasis OR
* A diagnosis of advanced solid tumor AND a T cell count of at least 1500 cells/uL OR a B cell count of at least 250 cells/uL at screening

Main Exclusion Criteria:

* Treatment with anti-neoplastic agents (chemotherapy, immunotherapy, radiotherapy or endocrine therapy) within 3 weeks prior to start of study treatment
* Treatment with an investigational agent within 4 weeks prior to start of study treatment
* Is on concurrent anti-neoplastic therapy with the exception of continuing luteinizing hormone-releasing hormone agonist/antagonist therapy for patients with castrate-resistant prostate cancer
* Treatment with oral or parenteral corticosteroids in excess of 10mg/day of prednisolone or equivalent for more than 5 days within 4 weeks prior to start of study treatment or a requirement for systemic immunosuppressive therapy for any reason
* Untreated brain Mets or CNS tumor involvement
* Any other intercurrent illness or condition which could impact patient compliance or ability to complete the study
* Sensitivity to VX15/2503 or the ingredients or excipients of VX15/2503
* Pregnant or breast-feeding women (women of child-bearing potential must have negative serum pregnancy test within 3 days prior to receiving the first dose of VX15/2503)