DISEASE CHARACTERISTICS: Histologically confirmed diagnosis of T-cell acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LBL) Leukemia or lymphoma cells should express at least two of the following cell surface antigens: CD1a, CD2, CD3 (surface or cytoplasmic), CD4, CD5, CD7, and CD8 Leukemia cells should be negative for myeloperoxidase or Sudan Black B If the only T cell markers present are CD4 and CD7, the leukemic cells should be demonstrated to lack the myeloid markers CD33 and/or CD13 Refractory to at least one induction treatment regimen or in first or later relapse after achieving a complete remission No CNS leukemia or lymphoma requiring intrathecal or craniospinal radiotherapy

PATIENT CHARACTERISTICS: Age: 16 and over Performance status: Not specified Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Bilirubin no greater than 2 times upper limit of normal (unless due to leukemia) Renal: Creatinine clearance at least 50 mL/min (unless due to leukemia) Neurologic: No neurologic toxicity of grade 3 or greater during prior treatment of ALL/LBL No preexisting neuropathy of grade 2 or greater regardless of causality Other: No history of seizure disorder Not pregnant or nursing Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent erythropoietin Chemotherapy: See Disease Characteristics No other concurrent chemotherapy Endocrine therapy: No concurrent dexamethasone or other steroidal antiemetics No concurrent hormone therapy, except for non-disease-related conditions Radiotherapy: See Disease Characteristics Surgery: Not specified