A Phase I/II Study to Investigate the Use of VORAXAZE™ As Intended Intervention in Patients with CNSL

Inclusion Criteria:

* Primary or secondary CNSL (PCNSL or SCNSL) confirmed by histology or cytology.
* Renal insufficiency defined as a glomerular filtration rate (GFR, assessed by CKD-EPI or MDRD equation) of 40-80 mL/min or patients with a GFR \>80mL/min who have experienced renal failure, defined as doubling of the serum creatinine compared to the baseline value during a previous HD-MTX treatment.
* Age ≥ 18 years (male or female).
* Life expectancy \>3 months.
* Adequate organ function (i.e., bone marrow, liver, lungs) allowing intensive chemotherapy with MTX.
* Adequate clinical pathology values:
* Absolute neutrophil count ≥1.0 x 109/L, hemoglobin ≥9mg/dL (transfusion allowed), platelets ≥100 x 109/L.
* Total bilirubin ≤1.5x the upper limit of normal except for patients with known Gilbert syndrome.
* Alanine amino-transferase (ALT) and aspartate amino-transferase (AST) ≤2x the upper limit of normal.
* Alkaline phosphatase ≤2x the upper limit of normal.
* Prothrombin time within the normal range for the institution.
* Signed informed consent by the patient or legal representative prior to start of any study specific procedure.
* Females of childbearing potential and males must be willing and able to use an adequate method of contraception to avoid pregnancy for the duration of the study in such a manner that the risk of pregnancy is minimized. Acceptable contraceptives include intra-uterine devices (IUDs), hormonal contraceptives (oral, depot, patch or injectable) and double barrier methods such as condoms or diaphragms with spermicidal gel or foam.

Exclusion Criteria:

* Ongoing or expected need for therapy with drugs interfering with MTX-clearance (i.e., beta-lactam antibiotics, NSAIDs, probenicid, salicylates, sulphonamides) or other nephrotoxic drugs.
* Prior brain radiotherapy within 28 days of first dose of the study drug.
* Concurrent illness interfering with hydration (i.e., relevant congestive heart failure, SIADH syndrome).
* Relevant third space (i.e., pleural effusion, ascites, extended edema) precluding HD-MTX treatment.
* Obesity (body mass index \>30 kg/m2).
* Uncontrolled diabetes.
* Active hepatitis.
* HIV-infection.
* Pregnant or lactating woman.
* Participation in any other clinical trial either 1 month prior to or during this study.
* Previous intolerance to any of the drugs used in this study (i.e., MTX, LV)