Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed metastatic or inoperable non-small cell
lung, breast, or colon cancer or duct cell carcinoma of the exocrine pancreas

- Bidimensionally measurable lesions that are not previously irradiated

- New lesions that have developed in a previously irradiated field may be used as
measurable disease

- No brain metastases

- Patients with prior brain metastases are allowed provided they have undergone
prior resection of metastases and/or 1 prior course of cranial irradiation, have
no new sites of brain metastases since then, have no worsening CNS symptoms, and
have discontinued prior corticosteroids for at least 30 days

- Hormone receptor status:

- Not specified

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Sex:

- Not specified

Menopausal status:

- Not specified

Performance status:

- ECOG 0-2

Life expectancy:

- Not specified

Hematopoietic:

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

Hepatic:

- Bilirubin no greater than 2 times upper limit of normal (ULN)

- AST or ALT no greater than 2 times ULN (5 times ULN if due to liver involvement)

Renal:

- Creatinine no greater than 1.5 times ULN

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 30 days after study
participation

- Capable of swallowing intact study medication capsules

- Capable of following instructions regarding study medication or has daily caregiver
to administer study medication

- No concurrent serious infection

- No life-threatening illness unrelated to tumor

- No other prior or concurrent malignancy within the past 3 years except nonmelanoma
skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 2 weeks since prior immunotherapy or biologic therapy

Chemotherapy:

- At least 4 weeks since prior cytotoxic chemotherapy

- No more than 1 prior cytotoxic chemotherapy regimen for metastatic non-small cell
lung or colon cancer

- No more than 2 prior cytotoxic chemotherapy regimens for breast cancer

- No prior cytotoxic chemotherapy for pancreatic cancer

Endocrine therapy:

- See Disease Characteristics

- At least 2 weeks since other prior hormonal therapy

Radiotherapy:

- See Disease Characteristics

- At least 3 weeks since prior radiotherapy and recovered

- No concurrent radiotherapy

Surgery:

- See Disease Characteristics

Other:

- No other concurrent anticancer agents