This clinical trial is focused on studying a rare type of cancer called Primary Central Nervous System Lymphoma (PCNSL), which affects the brain, spinal cord, or eyes. The trial aims to explore a new treatment approach for patients who have been newly diagnosed with this condition. The treatment being tested is a combination of medications known as MATRix, which includes Methotrexate, Ara-C (also known as Cytarabine), Thiotepa, and Rituximab. These medications are given as an initial therapy to see if a reduced duration and total dose can be as effective as the standard treatment. The study will also involve a high-dose therapy followed by a procedure called autologous stem cell transplantation, where a patient’s own stem cells are used to help recover from the treatment.

The purpose of this study is to determine if the new treatment strategy can improve the time patients remain free from events such as treatment failure, cancer progression, or death, compared to the standard approach. Participants in the study will receive the medications through an intravenous infusion, which means the drugs are delivered directly into the bloodstream. The study will compare the outcomes of the new treatment plan with the standard treatment to see which is more effective in helping patients achieve remission, which is a period when the cancer is not active.

Throughout the study, researchers will monitor various aspects of the participants’ health, including overall survival, progression-free survival, and quality of life. The trial is expected to continue until 2030, allowing researchers to gather comprehensive data on the effectiveness and safety of the new treatment approach. This study is an important step in finding better ways to treat PCNSL and improve the lives of those affected by this challenging condition.