The first purpose is to confirm or not the efficacy of only one administration of DepoCyte®.

It is a clinical study multicenter, prospective, open label trial, uncontrolled and nonrandomized

Inclusion Criteria:

• Patients with acute lymphoblastic leukemia or very aggressive Non-Hodgkin-Lymphoma (Burkitt/Burkitt-like) and CNS relapse.

CNS involvement must be demonstrated by:

• A positive ventricular or lumbar CSF cytology defined as CSF cell counts > 5/µl (19/3 cells), obtained within 10 days prior to inclusion OR
• Characteristic signs and symptoms of neoplastic meningitis PLUS an MRI or CT scan indicating the presence of meningeal involvement. Patients with combined relapse in CNS and other locations may be included in case that systemic therapy with CNS active drugs (HDMTX;HDAC, Thiotepa) can be postponed for at least 2 weeks.
• Karnofsky >60%
• Age >18 years old
• Recovery from grade III/IV toxicities attributable to prior treatment with the exception of hematotoxicity.
• No severe heart, lung, liver or kidney dysfunction.
• The patient or guardian must be competent to provide informed consent and must provide written informed consent prior to the initiation of study procedures

Exclusion Criteria:

• Failure (as defined by no clearance of the CSF) to > 1 dose of prior intrathecal MTX or cytarabine or triple (MTX, ARAC, dexamethasone) therapy
• History of previous severe neurotoxicity (grade III-IV) attributed to intrathecal therapy or systemic high-dose therapy with methotrexate or cytarabine (vincristine induced peripheral neuropathy is accepted)
• Prior CNS relapse < 1 month before
• uncontrolled infection
• The patient must not be pregnant or breast feeding. If the patient is a female of child-bearing potential she must have a negative (urine or serum) pregnancy test and be using effective methods to prevent pregnancy