Imatinib Mesylate and Bevacizumab After First-Line Chemotherapy and Bevacizumab in Treating Patients With Stage IIIB or Stage IV Non-Small Cell Lung Cancer

RATIONALE: Imatinib mesylate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Imatinib mesylate and bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. Giving imatinib mesylate together with bevacizumab as maintenance therapy may stop non-small cell lung cancer from growing or coming back. PURPOSE: This phase II trial is studying how well giving imatinib mesylate together with bevacizumab after first-line chemotherapy and bevacizumab works in treating patients with stage IIIB or stage IV non-small cell lung cancer.