Study to Evaluate Combined Treatment of Daratumumab, Bortezomib and Dexamethasone in PBL Patients.

This is an open-label, multicenter, phase II, single arm trial. Patients will be recruited over 18 months in 19 FIL centers and it is expected that a total of 28 patients will start treatment. Analysis of the primary endpoint of the study is planned approximately after 12 months from the enrollment of the last patient, regardless of the response to protocol treatment of this patient. The total duration of the study is 60 months (\~5 years). Patients will be enrolled based on the local diagnosis and the local assessment of CD38 expression ≥ 5%. The screening phase of the study includes baseline assessments according to local practice and those required by the study. Samples coming from the most recent biopsy, and if available also those used for the first diagnosis, are to be collected and sent afterwards, upon request of the FIL Offices, to one of the three FIL designed central laboratories. Central diagnosis review and CD38 assessment will be performed during or at the end of the study conductance; there's no need to wait for central results to start protocol treatment. Protocol treatment consists of an induction phase planning one course (cycle 1) of daratumumab sc as single agent followed by 8 courses (cycles 2-9) of daratumumab sc in combination with bortezomib sc and dexamethasone (DVd regimen). Patients achieving at least a SD after induction will be addressed to the maintenance phase, planning a maximum of 6 cycles (cycles 10-15) of daratumumab sc as single agent. Induction cycles will be administered every 21 days, while maintenance cycles will be administered every 28 days. Treatment with DVd or daratumumab single agent will be discontinued before completion of planned cycles in case of disease progression, unacceptable toxicity, withdrawal of consent and/or the investigator determines that further therapy is not in the patient best interest (e.g., due to non-compliance, toxicity, etc.). Adverse events according to CTCAE will be monitored from the first dose of induction treatment, throughout maintenance phase and for 30 days after the last dose of protocol treatment with the study drug or 30 days after the last dose of drug in case of early discontinuation from any cause.