Study of Sorafenib Maintenance in Patients With ED-SCLC After Response to Induction Chemotherapy

Inclusion criteria: * Histologically or cytologically confirmed ED-SCLC patients who have achieved a complete or partial response after four to six cycles of platinum based induction chemotherapy. * Extensive stage SCLC is defined as disease not meaning the definition of limited stage disease * Previous radiotherapy is allowed only if \< 30% of marrow bearing bones were irradiated and if radiotherapy was completed at least 2 weeks prior to enrollment and the patient has recovered from all adverse effects of prior radiotherapy. * Age \>18 years. * Written informed consent that is consistent with ICH-GCP guidelines * Life expectancy of greater than 3 months. * ECOG performance status 2 (Karnofsky ≥50%). * Ability to swallow oral medication * Women of childbearing potential must have a negative serum pregnancy test performed within 7 days prior to the start of treatment * Both men and women enrolled in this trial must use adequate barrier birth control measures during the course of the trial and during the first 3 months after the completion of trial * Adequate bone marrow, liver and renal function Exclusion Criteria: * History of cardiac disease/ HIV infection / chronic hepatitis B or C / of organ allograft * Active clinically serious infections * Patients with seizure disorder requiring medication or evidence or history of bleeding diathesis or coagulopathy * Patients undergoing renal dialysis * Pulmonary hemorrhage/ bleeding event ≥ CTCAE grade 2 within four weeks * Any other hemorrhage/ bleeding event ≥ CTCAE grade 3 within four weeks * Non-healing wound, ulcer or bone fracture * Thrombotic or embolic venous or arterial events of study drug * Previous or concurrent cancer that is distinct in histology of primary site, EXCEPT cervical carcinoma in situ, treated basal cell carcinoma, superficial bladder tumors (Ta, Tis, T1). Any cancer curatively treated \>3 years prior to entry is permitted. * Substance abuse, medical, psychological or social conditions that may interfere with the subject's participation in the study or evaluation of the study results * Known or suspected allergy or any other contraindication for Sorafenib administration * Pregnant or breast-feeding women. * Any disease which could affect the evaluation of the study drug * Any condition that is unstable or could jeopardize the safety of the subject and their compliance in the study * Any condition which could affect the absorption or pharmacokinetics of the Study drug including any type of gastrointestinal resection or surgery * Uncontrolled symptomatic brain metastasis Excluded therapies and medications, previous and concomitant: * Investigational drug or device therapy including outside of this trial during or within 4 weeks prior to study entry (signing Informed Consent). * The toxicity effects of previous antitumor chemotherapy or immunotherapy must be resolved to less than CTC Grade 2 level (exception: alopecia). * Prior treatment with other VEGFR inhibitors (i.e. sunitinib, thalidomide, vandetanib and other experimental agents of this class). * Major surgery within 4 weeks prior to start of study (Informed Consent signature). Minimal invasive biopsy is allowed. * Use of biologic response modifiers, such as G-CSF, within 3 weeks prior to study entry. \[Therapeutic G-CSF and other hematopoietic growth factors may be used in the management of acute toxicity such as febrile neutropenia when clinically indicated or at the discretion of the investigator, however they may not be substituted for a required dose reduction\]. * Any agents which could affect the absorption or pharmacokinetics of the study drug * Prior exposure to the study drug * Therapeutic anticoagulation with vitamin K antagonists such as warfarin, or with heparins or heparinoids. Prophylactic low dose warfarin (1 mg po qd) is permitted if the INR (International normalized ratio) is ≤ 1.5. Low-dose aspirin is permitted (80-100 mg daily).