Inclusion Criteria:

- Male or female subjects, aged 18 years or older with unresectable or metastatic
melanoma.

- A life expectancy of >12 weeks.

- Laboratory ranges and medical criteria met, as defined within the protocol.

- Subject may not have received more than 1 prior regimen of systematic treatment for
unresectable or metastatic melanoma.

- For Phase 2 period of the study only, Subjects must have archival tumor tissue
available and collected with the prior 6 months or accessible disease for
pre-treatment, study biopsy.

Exclusion Criteria:

- Pregnant or nursing women.

- Current investigational trial participation with another investigational product or
subjects who have received any anticancer medications within 21 days prior to
screening (6 weeks for mitomycin-C or nitrosoureas.)

- Subjects receiving monoamine oxidase inhibitors (MAOI)s; subjects who have ever had
Serotonin Syndrome after receiving one or more serotonergic drugs.

- Subjects who have ever received prior therapy with anti-CTLA-4 antibody, anti PD-1,
or an experimental immune system-targeted therapy.

- Subjects with protocol-specified active autoimmune process except vitiligo or
thyroiditis.

- Subjects with concurrent conditions that would jeopardize the safety of the safety of
the subject or compliance with the protocol.