Inclusion Criteria

DISEASE CHARACTERISTICS:

- Cytologically or histologically confirmed diagnosis of advanced hepatocellular
carcinoma (HCC) or renal cell carcinoma; HCC patients should not be amenable to
treatment with surgery or to orthotopic liver transplant (phase I)

- Cytologically or histologically confirmed diagnosis of hepatocellular carcinoma that
is locally advanced or metastatic and is not amenable to treatment with surgery or to
orthotopic liver transplant (phase II)

- Patients must have measurable disease

- HCC patients only:

- Advanced HCC after first-line (i.e., no prior systemic therapy) or second-line
(with prior first-line sorafenib tosylate therapy only) treatment (phase I)

- Advanced HCC after first-line treatment (i.e., no prior systemic therapy) (phase
II)

- Child Pugh class A or B7 liver disease

- Prior chemoembolization, radioembolization, radiofrequency ablation (RFA), or
other local ablative therapies are permissible if ≥ 6 weeks from procedure with
evidence of progression or new metastatic disease, if applicable

- No known central nervous system (CNS) or brain metastasis that is either symptomatic
or untreated

- Patients with neurological symptoms must undergo a computed tomography (CT)
scan/magnetic resonance imaging (MRI) of the brain to exclude brain metastasis

- Patients with CNS metastases that have been treated and are stable without
symptoms for ≥ 4 weeks after completion of treatment are eligible

- HCC patients only: cancer potentially amenable to local modalities of therapy or
surgical resection not allowed

- No fibrolamellar histology HCC, mixed hepatocholangiocarcinoma, hepatic sarcomas, and
other non-HCC primary liver tumors

PATIENT CHARACTERISTICS:

- ECOG performance status 0 or 1

- Life expectancy ≥ 3 months

- Absolute neutrophil count ≥ 1,200/mm³

- Peripheral platelet count ≥ 75,000/mm³

- Hemoglobin > 8.5 g/dL

- Total bilirubin ≤ 3.0 times upper limit of normal (ULN)

- AST and ALT ≤ 2.5 times ULN (if patient has HCC or liver metastases, then ≤ 5 times
ULN) (phase I)

- Creatinine ≤ 1.5 times ULN

- International normalized ratio (INR) ≤ 1.5 times ULN

- Negative pregnancy test done ≤ 7 days prior to registration, for women of
childbearing potential only

- Willing to return to North Central Cancer Treatment Group (NCCTG) enrolling
institution for follow-up

- Ability to receive intravenous contrast for the purpose of imaging (phase II)

- None of the following:

- Pregnant women

- Nursing women

- Men or women of childbearing potential who are unwilling to employ adequate
contraception for the duration of study participation; men and women should
continue to use adequate birth control after the last administration of
sorafenib tosylate and hypoxia-activated prodrug TH-302 (TH-302) under the
guidance of their treating physician

- No co-morbid systemic illnesses or other severe concurrent disease which, in the
judgment of the investigator, would make the patient inappropriate for entry into
this study or interfere significantly with the proper assessment of safety and
toxicity of the prescribed regimens

- No other active malignancy ≤ 3 years prior to registration; EXCEPTIONS: non-melanotic
skin cancer or carcinoma-in-situ of the cervix; NOTE: if there is a history or prior
malignancy, they must not be receiving other specific treatment (other than hormonal
therapy) for their cancer

- No inadequately controlled hypertension (systolic blood pressure of > 150 mm Hg or
diastolic pressure > 100 mm Hg on anti-hypertensive medications)

- No New York Heart Association (NYHA) classification III or IV congestive heart
failure

- No known or suspected allergy or hypersensitivity to any component of TH-302,
sorafenib tosylate, or any of the sorafenib tosylate excipients

- No condition that severely impairs patient's ability to swallow whole pills

- No QTc interval > 500 msec on baseline electrocardiogram (EKG)

- No documented history of prolonged QTc interval ≤ 6 months prior to registration

- No traumatic injury in the past 14 days

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Not receiving any other investigational agent

- No major surgical procedures prior to registration or anticipation of need for
elective or planned major surgical procedure during the course of the study

- No treatment with radiation therapy or investigational therapy ≤ 28 days prior to
registration

- RCC patients only: No chemotherapy prior to study entry within 5 half-lives of the
agent (as described in the package insert), or 4 weeks prior to registration
(whichever is shorter) with resolution of side effects from therapy to ≤ grade 1

- No medication that has documented data or is generally accepted as having increased
risk of QT prolongation and/or Torsades de Pointes

- Not receiving any medications or substances that are inducers or strong or moderate
inhibitors of CYP3A4 ≤ 7 days prior to registration

- Patients receiving anti-coagulation therapy are permitted as long as they have a
stable INR ≤ 3.0