DISEASE CHARACTERISTICS: Histologically confirmed stage III or IV ovarian epithelial cancer, including fallopian tube and extraovarian carcinoma Cytological confirmation in the presence of clear clinical and radiological features of disease allowed Refractory to at least two prior chemotherapy regimens for advanced or metastatic disease At least one taxane/platinum containing regimen with or without one topotecan regimen Recurrent or progressive disease while on or within 6 months of last therapy regimen Must have progressed on or within 3 months of receiving topotecan as last therapy regimen Measurable disease outside previously irradiated field OR Objective evidence of disease progression if within previously irradiated field CA 125 at least 35 units/mL No CNS metastases or carcinomatous meningitis

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 12 weeks Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hemoglobin at least 9.0 g/dL Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) AST and ALT no greater than 3 times ULN (no greater than 5 times ULN if liver metastases present) Albumin greater than 2.5 g/dL Renal: Creatinine no greater than ULN Other: No known hypersensitivity to sulfa compounds No known glucose-6-phosphate dehydrogenase deficiency No active or uncontrolled infection No other malignancy within the past 2 years No other severe disease including neurologic or psychiatric disorders that would preclude study Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy and recovered No other concurrent chemotherapy Endocrine therapy: No concurrent hormonal therapy, excluding contraceptives or corticosteroids Radiotherapy: See Disease Characteristics Prior radiotherapy to less than 25% bone marrow allowed No prior whole pelvic radiotherapy At least 4 weeks since prior radiotherapy and recovered No concurrent radiotherapy Surgery: At least 4 weeks since prior major surgery and recovered Other: At least 4 weeks since prior investigational agents No other concurrent investigational agents