Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed colorectal cancer
Unresectable disease Measurable disease No uncontrolled brain metastases

PATIENT CHARACTERISTICS: Age: Any age Performance status: SWOG 0-2 Life expectancy: At
least 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count
at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal
(ULN) AST no greater than 2.5 times ULN Renal: Creatinine no greater than 1.5 times ULN
Other: No active infection Not pregnant or nursing Negative pregnancy test for
premenopausal women Fertile patients must use effective contraception No concurrent
uncontrolled systemic disorders No prior malignant disease within the past year except in
situ carcinoma of the cervix or curatively treated basal cell carcinoma of the skin No
history of allergy to bryostatin 1 or its vehicle

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy Chemotherapy: Only
one prior chemotherapy regimen in the adjuvant or metastatic setting allowed At least 3
weeks since prior chemotherapy (6 weeks for nitrosoureas) No other concurrent chemotherapy
Endocrine therapy: No concurrent hormonal therapy (except contraceptives, appetite
stimulants and replacement steroids) Radiotherapy: At least 3 weeks since prior
radiotherapy No concurrent radiation therapy No concurrent palliative radiation therapy to
only site of measurable disease Surgery: Not specified Other: At least 1 month since prior
use of any other investigational agent No concurrent use of experimental medications