Oblimersen and Dacarbazine in Treating Patients With Advanced Malignant Melanoma That Has Responded to Treatment on Clinical Trial GENTA-GM301

DISEASE CHARACTERISTICS: * Histologically confirmed advanced malignant melanoma * Unresectable or metastatic disease * Previously enrolled on GENTA-GM301 protocol * Complete or partial objective response or stable disease after completion of 8 courses of oblimersen (G3139) and dacarbazine on arm II of GENTA-GM301 * Measurable or evaluable disease * No uncontrolled brain metastases or leptomeningeal disease PATIENT CHARACTERISTICS: Age * Any age 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\* * Hemoglobin at least 8 g/dL\* NOTE: \*Hematopoietic growth factor or transfusion independent Hepatic * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * AST and ALT no greater than 2.5 times ULN * Alkaline phosphatase no greater than 2.5 times ULN * Albumin at least 2.5 g/dL * PTT no greater than 1.5 times ULN * PT no greater than 1.5 times ULN OR * INR no greater than 1.3 * No history of chronic hepatitis or cirrhosis Renal * Creatinine no greater than 1.5 times ULN OR * Creatinine clearance at least 50 mL/min Cardiovascular * No uncontrolled congestive heart failure * No active symptoms of coronary artery disease, defined as uncontrolled arrhythmias or recurrent chest pain despite prophylactic medication * No New York Heart Association class III or IV heart disease * No cardiovascular signs and symptoms grade 2 or greater within the past 4 weeks Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No other significant medical disease * No uncontrolled seizure disorder * No active infection * No uncontrolled diabetes mellitus * No active autoimmune disease * No known hypersensitivity to phosphorothioate-containing oligonucleotides or dacarbazine * No intolerance to prior oblimersen and dacarbazine, including discontinuation of protocol therapy due to 1 or more adverse events * HIV negative * Satisfactory venous access for a 5-day continuous infusion * Intellectually, emotionally, and physically able to maintain an ambulatory infusion pump PRIOR CONCURRENT THERAPY: Biologic therapy * At least 4 weeks since prior biologic therapy, immunotherapy, cytokine therapy, or vaccine therapy and recovered * No concurrent anticancer biologic therapy Chemotherapy * See Disease Characteristics * No other concurrent anticancer chemotherapy Endocrine therapy * No concurrent chronic corticosteroids (average dose of at least 20 mg/day of prednisone or equivalent) Radiotherapy * At least 4 weeks since prior radiotherapy and recovered * No concurrent anticancer radiotherapy Surgery * At least 4 weeks since prior major surgery and recovered Other * At least 4 weeks since other prior therapy and recovered * More than 3 weeks since prior experimental therapy (except for GENTA-GM301 protocol) * No intervening systemic therapy for melanoma since completion of GENTA-GM301 protocol therapy * No other concurrent anticancer therapy, including investigational therapy * No concurrent immunosuppressive drugs * No concurrent anticoagulation therapy * Concurrent warfarin (1 mg/day) for central line prophylaxis is allowed