Inclusion Criteria:

- Patients must have measurable, histologically confirmed, advanced unresectable or
metastatic gastric or GEJ adenocarcinoma; imaging studies must be conducted within 4
weeks of study entry

- For patients with GEJ adenocarcinoma, the tumor location should be specified using
the Siewert classification used in other NCI-sponsored Phase II studies in these
disease sites

- Patients must have an ECOG performance status of 0-1

- Patients may have had adjuvant chemotherapy or chemoradiation therapy, with or
without 5-Fluorouracil if the treatment was performed more than 6 months before any
evidence of recurrent or metastatic disease

- Patients must NOT have had any previous radiotherapy, chemotherapy or investigational
therapies, particularly inhibitors of tyrosine Kinases, signal transduction or
angiogenesis in the treatment for THEIR RECURRENT and/or METASTATIC gastric or GEJ
adenocarcinoma

- Patients may not be receiving any other investigational agents

- The effects of BAY 43-9006 on the developing human fetus at the recommended
therapeutic dose are unknown; for this reason and because raf kinase inhibitor agents
as well as other therapeutic agents used in this trial are known to be teratogenic,
women of child-bearing potential and men must agree to use adequate contraception
(hormonal or barrier method of birth control; abstinence) prior to study entry and
for the duration of study participation; should a woman become pregnant or suspect
she is pregnant while participating in this study, she should inform her treating
physician immediately; women must not be pregnant or breast-feeding; all females of
childbearing potential must have a blood or urine test within 2 weeks prior to
randomization to rule out pregnancy

- Women of childbearing potential and sexually active males must be strongly advised to
use an accepted and effective method of contraception

- Patients with immune deficiency are at increased risk of lethal infections when
treated with marrow-suppressive therapy; therefore, HIV-positive patients receiving
combination antiretroviral therapy are excluded from the study because of possible
pharmacokinetic interactions with BAY 43-9006

- Patients must not have known brain metastases because of their poor prognosis and
because they often develop progressive neurologic dysfunction that would confound the
evaluation of neurologic and other adverse events

- Patients must not have a history of allergic reactions attributed to compounds of
similar chemical or biologic composition to BAY 43-9006

- Absolute Granulocyte Count >= 1,500/mm^3

- Platelet Count >= 100,000/mm^3

- White Blood Count >= 3,000/mm^3

- Serum Creatinine =< 1.5 mg/dl

- Total Bilirubin =< 2.0 mg/dl

- AST/ALT/Alk phos =< 2.5 x ULN

- Patients must not have an acute active infection with significant clinical
intervention per physician's discretion

- Previous or concurrent malignancies are not allowed, except:

- Non-melanoma skin cancer and in situ cervical cancer

- Treated cancer from which the patient has been continuously disease-free for
more than five years

- Patients must not have other uncontrolled intercurrent illnesses including, but not
limited to: uncontrolled hypertension, symptomatic congestive heart failure, unstable
angina pectoris, cardiac arrhythmia or psychiatric illness/addictive disorders that
would limit compliance with study requirements

- Patients must not have any evidence of bleeding diathesis

- Patients must be able to take oral medication without crushing, dissolving or chewing
tablets

- Patients must not be taking the following cytochrome P450 enzyme-inducing
anti-epileptic drugs:

- Phenytoin

- Carbamazepine

- Phenobarbital

- Rifampin

- St. John's Wort