Inclusion Criteria:

- Histologically confirmed ovarian epithelial or primary peritoneal carcinoma

- Persistent or recurrent disease

- Measurable or evaluable disease

- Measurable disease is defined as at least 1 unidimensionally measurable lesion ≥
20 mm by conventional techniques (including palpation, plain x-ray, CT scan, or
MRI) OR ≥ 10 mm by spiral CT scan

- Evaluable disease is defined as at least 1 of the following:

- CA 125 ≥ 2 times upper limit of normal (ULN)

- Ascites and/or pleural effusion attributed to tumor

- Solid and/or cystic abnormalities on radiographic imaging that do not meet
RECIST definition for target lesions

- Must have received 1 prior platinum-based chemotherapeutic regimen for primary
disease, including carboplatin, cisplatin, or another organoplatinum compound

- Initial treatment may have included high-dose therapy, consolidation, or
extended therapy administered after surgical or non-surgical assessment

- Platinum-resistant according to 1 of the following criteria:

- Treatment-free interval of < 12 months after platinum therapy

- Disease progression during platinum-based therapy

- Persistent disease after a platinum-based regimen

- Ineligible for higher priority GOG protocol (e.g., any active phase III GOG protocol
for the same patient population)

- No brain metastases

- Performance status - GOG 0-2 (for patients who received 1 prior treatment regimen)

- Performance status - GOG 0-1 (for patients who received 2 prior treatment regimens)

- Absolute neutrophil count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

- No known bleeding diathesis

- Bilirubin ≤ 1.5 times ULN

- SGOT ≤ 2.5 times ULN

- Alkaline phosphatase ≤ 2.5 times ULN

- Creatinine ≤ 1.5 times ULN

- No symptomatic congestive heart failure

- No unstable angina pectoris

- No cardiac arrhythmia

- No uncontrolled hypertension

- Able to take oral medication

- No bowel obstruction or persistent vomiting

- No requirement for parenteral feedings

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective barrier contraception during and for 3 months
after study participation

- No sensory or motor neuropathy > grade 1

- No active or ongoing infection requiring antibiotics

- No history of allergic reaction attributed to compounds of similar chemical or
biological composition to sorafenib

- No serious chronic skin conditions (i.e., psoriasis or dermatitis) that would
preclude study participation

- No psychiatric illness or social situation that would preclude study compliance

- No other uncontrolled illness

- No other invasive malignancy within the past 5 years except nonmelanoma skin cancer

- At least 3 weeks since prior immunologic agents for the malignancy

- More than 4 weeks since prior mouse antibodies (for patients with evaluable disease
only)

- No concurrent prophylactic growth factors (e.g., filgrastim [G-CSF])

- No concurrent prophylactic thrombopoietic agents except in the case of recurrent
grade 4 thrombocytopenia

- No other concurrent biological agents for the primary tumor

- See Disease Characteristics

- More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin)
and recovered

- No prior non-cytotoxic chemotherapy for persistent or recurrent disease

- No concurrent chemotherapy for the primary tumor

- At least 1 week since prior hormonal therapy for the malignancy

- No concurrent hormonal therapy for the primary tumor

- Concurrent hormone replacement therapy allowed

- More than 4 weeks since prior radiotherapy and recovered

- No prior radiotherapy to > 25% of marrow-bearing areas

- No concurrent radiotherapy

- More than 4 weeks since prior surgery involving the peritoneum or pleura (for
patients with evaluable disease only)

- Recovered from prior surgery

- At least 3 weeks since other prior therapy for the malignancy

- No more than 1 additional prior cytotoxic regimen for persistent or recurrent
disease

- No prior sorafenib

- No prior anticancer treatment that would preclude study participation

- No concurrent therapeutic oral anticoagulation therapy (i.e., warfarin)

- Concurrent prophylactic anticoagulation (i.e., low-dose warfarin) for central
venous access devices allowed provided INR is < 1.5

- No concurrent combination antiretroviral therapy for HIV-positive patients

- No other concurrent investigational or commercial agents or therapies for the
malignancy