RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die.

PURPOSE: Phase II trial to study the effectiveness of irofulven in treating patients with metastatic colorectal cancer.

OBJECTIVES: I. Assess the antitumor activity of 6-hydroxymethylacylfulvene (MGI-114) when given daily for 5 days every 28 days to patients with metastatic adenocarcinoma of the colon or rectum. II. Evaluate the qualitative and quantitative toxicities of MGI-114 given on this schedule in this patient population.

OUTLINE: Patients receive 6-hydroxymethylacylfulvene (MGI-114) IV over 5 minutes daily for 5 consecutive days. Courses are repeated every 28 days. The minimum treatment period is 2 courses. Treatment continues indefinitely in the absence of unacceptable toxic effects or disease progression. Patients are followed at the end of every other course while on the study, and then every 3 months thereafter until death.

PROJECTED ACCRUAL: A total of 18-35 patients will be accrued for this study within 6-10 months.

DISEASE CHARACTERISTICS: Histologically confirmed metastatic adenocarcinoma of the colon or rectum Bidimensionally measurable lesions Sentinel lesions outside the field of any prior radiation therapy No confirmed or suspected brain metastases

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-1 Life expectancy: At least 12 weeks Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 mg/dL Renal: Creatinine no greater than 1.5 mg/dL Creatinine clearance at least 60 mL/min Cardiovascular: No active congestive heart failure No uncontrolled angina At least 6 months since prior myocardial infarction No uncontrolled hypertension Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No concurrent serious infection No other malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix No overt psychosis or mental disability No life threatening illness (unrelated to tumor)

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent biologic therapy Chemotherapy: No prior chemotherapy for metastatic disease At least 6 months since prior adjuvant chemotherapy No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiation therapy and recovered No concurrent radiotherapy Surgery: At least 4 weeks since prior major surgery and recovered No concurrent surgery Other: At least 28 days since prior administration of any investigational drug No other concurrent anticancer therapy