Prior treatment for PCNSL with the exception of a pre-phase treatment comprising steroid treatment and / or single application of rituximab 375 mg/m² and methotrexate 3.5 g/m²

Systemic lymphoma manifestation outside the CNS

Diagnosis of previous Non-Hodgkin lymphoma at any time

Primary vitreoretinal or leptomeningeal lymphoma without manifestation in the brain parenchyma or spinal cord

HIV infection of any stage as determined by presence of anti-HIV antibodies (confirmatory test) and / or presence of RNA confirmed by PCR

Previous or concurrent malignancies with the following exceptions:

• Surgically cured carcinoma in-situ
• Other kinds of cancer without evidence of disease for at least 5 years

Hypersensitivity to study treatment or any component of the formulation

Stomatitis or gastrointestinal ulcerations preventing the use of methotrexate

Hepatitis B, hepatitis C or hepatitis E infection as determined by PCR

Severe active infection

Congenital or acquired immunodeficiency including previous organ transplantation

Pregnant or nursing (lactating) women.

Lack of accountability and inability to appreciate the nature, meaning and consequences of the trial and to formulate their own wishes correspondingly

Non-compliance, for reasons including, but not limited to the following:

1. Increased alcohol consumption, drug dependency or substance abuse that would interfere with cooperation with requirements of the trial
2. Refusal of blood products during treatment
3. Any similar circumstances that appear to make protocol treatment or long-term follow-up impossible

Relationship of dependence or employer-employee relationship to the sponsor or the investigator