Comparison of Nexavar/Placebo as Maintenance Therapy for Patients With Advanced Ovarian or Primary Peritoneal Cancer

Inclusion Criteria:

- Histologically confirmed International Federation of Gynecology and Obstetrics (FIGO)
stage (67) III or IV ovarian epithelial cancer or primary peritoneal cancer at
presentation. Patients must have achieved a clinical complete response (disappearance
of all clinical and radiological evidence of tumor) after only one regimen (4-6
cycles) of platinum and taxane-based standard chemotherapy received after tumor
debulkment.

- Normal serum CA125 (cancer-associated tumor marker) level within 7 days of first dose
of sorafenib.

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

- All scans used to document complete response must be done within 30 days prior to
randomization.

- Patients must be able to swallow and retain oral medication.

Exclusion Criteria:

- Patients with any residual cancer tissue after the completion of chemotherapy
detectable by standard Computed tomography (CT) or magnetic resonance imaging (MRI).

- Prior local radiotherapy, neoadjuvant chemotherapy or intraperitoneal chemotherapy.

- Histologic subtypes of ovarian cancer other than epithelial (i.e. sarcoma, lymphoma,
germ cell).

- Major surgery, open biopsy, or significant traumatic injury within 30 days prior to
randomization.