Topotecan and Paclitaxel in Treating Patients With Advanced Non-small Cell Lung Cancer or Other Advanced Solid Tumors

DISEASE CHARACTERISTICS: Phase I: Advanced solid tumors, including non-small cell lung cancer (NSCLC), that have failed conventional therapy or for which no standard effective therapy exists May have failed conventional chemotherapy for tumor type Chemotherapy naive NSCLC allowed Measurable or evaluable disease Phase II: Stage IIIB or IV NSCLC not amenable to surgery or radiotherapy with curative intent No prior chemotherapy allowed At least 1 bidimensionally measurable non-CNS indicator lesion defined by diagnostic studies Measurable disease on CT or MRI scan must have one diameter at least 1 cm and one diameter at least 2 cm Measurable disease on chest x-ray must have both diameters at least 2 cm Palpable tumor masses that cannot be evaluated radiologically must have two diameters at least 2 cm Measurable skin lesion must have at least one diameter at least 1 cm and its presence must be evaluated by a photograph At least 6 weeks since prior radiotherapy to measurable, progressive disease No brain and/or leptomeningeal metastases by CT or MRI brain scan unless asymptomatic on neurologic exam and not receiving corticosteroid therapy to control symptoms PATIENT CHARACTERISTICS: Age: 18 and over Performance status: WHO 0-2 Life expectancy: At least 12 weeks Hematopoietic: WBC at least 3,000/mm3 Neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin normal SGOT/SGPT no greater than 1.5 times upper limit of normal (ULN) (5 times ULN if liver metastases present) Alkaline phosphatase no greater than 1.5 times ULN (5 times ULN if liver metastases present) Renal: Creatinine no greater than 1.5 mg/dL OR Creatinine clearance at least 60 mL/min Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception for 3 months prior to and during study Able to take oral medication No active infection No other prior or concurrent malignancies except basal cell or squamous cell carcinoma of the skin or carcinoma in situ of the cervix No other severe medical problem unrelated to malignancy that would preclude study compliance or expose patient to extreme risk No condition of the gastrointestinal (GI) tract or otherwise that would affect GI absorption and motility No history of hypersensitivity reactions to paclitaxel or other drugs formulated in polyoxyethylated castor oil PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy Chemotherapy: See Disease Characteristics No other concurrent chemotherapy Endocrine therapy: See Disease Characteristics Radiotherapy: See Disease Characteristics At least 4 weeks since palliative radiotherapy and recovered No prior radiotherapy to greater than 30% of bone marrow reserve No concurrent radiotherapy Surgery: See Disease Characteristics At least 4 weeks since prior surgery (lesser period acceptable if deemed in best interest of patient) Other: No concurrent metoclopramide or cisapride to maintain motility or gastric emptying At least 30 days or 5 half-lives since other prior investigational drugs for treatment of cancer No other concurrent investigational medication