An International, Randomized, Double-Blinded, Phase 3 Efficacy Study of XL184 Versus Placebo in Subjects With Unresectable, Locally Advanced, or Metastatic Medullary Thyroid Cancer

Inclusion Criteria:

- The subject has a histologically confirmed diagnosis of MTC that is cannot be removed
by surgery, is locally advanced, or has spread in the body.

- The subject is at least 18 years old.

- The subject has an ECOG (Eastern Cooperative Oncology Group) performance status ≤ 2.

- The subject has documented worsening of disease (progressive disease) at screening
compared with a previous CT scan or MRI image done within 14 months of screening.

- The subject has recovered from clinically significant adverse events (side effects)
due to any other medications that were administered prior to randomization.

- The subject has adequate organ and bone marrow function.

- Subjects who are sexually active (male and female) must agree to use medically
accepted methods of contraception during the course of the study and for 3 months
following discontinuation of study treatments.

- The subject has no other diagnosis of cancer (unless non-melanoma skin cancer, an
early form of cervical cancer, or another cancer diagnosed ≥ 2 years previously) and
currently has no evidence of malignancy (unless non-melanoma skin cancer or an early
form of cervical cancer).

- Female subjects of childbearing potential must have a negative pregnancy test at
screening.

Exclusion Criteria:

- The subject has received prior treatment for their cancer within 4 weeks of
randomization (6 weeks for nitrosoureas or mitomycin C).

- The subject has received radiation to ≥ 25 % of bone marrow.

- The subject has received treatment with other investigational agents (unapproved
therapies) within 4 weeks of randomization.

- The subject has received treatment with XL184.

- The subject has brain metastases or spinal cord compression, unless completed
radiation therapy ≥ 4 weeks prior to randomization and stable without steroid and
without anti-convulsant treatment for ≥ 10 days.

- The subject has a history of clinically significant episodes of vomiting blood or a
recent history of vomiting > 2.5 mL (about 1/2 teaspoon) of red blood

- The subject has serious illness other than cancer

- The subject is pregnant or breastfeeding.

- The subject has an active infection requiring ongoing treatment.

- The subject is incapable of understanding and complying with the protocol or unable
to provide informed consent.