Inclusion Criteria:

- Histologically confirmed melanoma that is surgically incurable Note: Prior therapies
for melanoma, including cancer vaccines, are permitted but are not required. There is
no limit to the number of prior regimens for melanoma a patient may have received.

- Evidence of at least one lesion

- Eastern Cooperative Oncology Group (ECOG) performance status 0-1

- CT scan of the brain with contrast or MRI of the brain within 6 weeks prior to
enrollment showing no evidence of active brain metastases. PET scans and PET/CT
scans are also acceptable.

Exclusion Criteria:

- Previous treatment with other anti CTLA4 agents (eg, ipilimumab, MDX 010).

- Previously randomized to Pfizer study A3671009: A Phase 3, Open Label, Randomized
Comparative Study of CP 675,206 and Either Dacarbazine or Temozolomide in Patients
with Advanced Melanoma.

- History of chronic autoimmune disease (eg, Addison's disease, multiple sclerosis,
Graves disease, Hashimoto's thyroiditis, psoriasis, rheumatoid arthritis, systemic
lupus erythematosus, hypophysitis, etc.).

- History of inflammatory bowel disease (eg, Crohn's disease or ulcerative colitis),
celiac disease, or other chronic gastrointestinal conditions associated with
diarrhea, or current acute colitis of any origin, and any history of diverticulitis
(even a single episode) or evidence of diverticulitis at baseline, including evidence
limited to CT scan only.

- Brain metastases that have not been adequately treated with surgery or stereotactic
radiosurgery and have not been stable at least 3 months prior to enrollment.