Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically proven metastatic non-small cell lung cancer
Eligible subtypes: Adenocarcinoma Squamous cell carcinoma Large cell carcinoma At least 1
bidimensionally measurable lesion, at least 2 cm by 2 cm in perpendicular diameter on
radiologic study Previously irradiated bony lesions are not considered measurable unless
there is evidence of disease progression at that site prior to study No brain metastases

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy:
More than 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet
count at least 100,000/mm3 Hemoglobin at least 9 g/dL Hepatic: Bilirubin no greater than 2
times upper limit of normal (ULN) SGOT and SGPT no greater than 2 times ULN (5 times ULN
if documented liver metastases) Alkaline phosphatase no greater than 2 times ULN (5 times
ULN if documented liver metastases) Renal: Blood urea nitrogen no greater than 1.5 times
ULN Creatinine no greater than 1.5 times ULN Other: No active nonmalignant systemic
disease that would increase risk No frequent vomiting or medical condition that would
interfere with oral medication intake (e.g., partial bowel obstruction) No other
malignancy within the past 5 years except surgically cured carcinoma in situ of the cervix
or basal cell or squamous cell skin cancer HIV negative No AIDS-related illness Not
pregnant or nursing Negative pregnancy test Fertile patients must use effective
contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy or biologic
therapy No concurrent growth factors or epoetin alfa Chemotherapy: At least 4 weeks since
prior chemotherapy No more than 1 prior chemotherapy regimen for metastatic disease No
other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease
Characteristics Prior radiotherapy for local control or as palliative therapy for a
painful bony lesion allowed No prior radiotherapy to 50% or more of bone marrow At least 4
weeks since prior radiotherapy to 15% or more of bone marrow (2 weeks for radiotherapy to
less than 15% of bone marrow) and recovered No concurrent radiotherapy Surgery: Not
specified Other: Recovered from any prior therapy No other concurrent investigational
drugs