Copanlisib and Rituximab in Marginal Zone Lymphoma Patients

For marginal zone lymphoma (MZL) Rituximab in combination with conventional chemotherapy is widely used for those patients who fail local therapy or do not qualify for such. Depending on the MZL subtype Rituximab/chemotherapy is able to induce in part long remissions, but do not prevent relapse later on. In addition, chemotherapy associated toxicity is often problematic in MZL patients, who are mostly of advanced age. Thus, chemotherapy - free approaches are highly attractive for this patient group. Rituximab single agent is a widely used chemotherapy - free approach in MZL, but was significantly inferior compared to Rituximab/chlorambucil in a large randomized prospective clinical trial in treatment naïve MZL with a CR rate of 56 % vs. 80%, respectively (P\<0.001). Thus, it is the major aim to develop chemotherapy - free approaches for MZL, which approach efficacy of Rituximab/chemotherapy combinations, but avoid chemotherapy associated toxicities. This in particular important in MZL as many physicians are reluctant to treat these often elderly patients with more intense treatments and prefer single agent therapies in these very often well and long responding lymphoma subtype. The PI3K inhibitor Copanlisib has shown high clinical activity in indolent B - cell lymphomas among them MZL. Based on these observations it is the aim of this study to test the toxicity and efficacy of Copanlisib in combination with the anti-CD20 antibody Rituximab in patients with newly diagnosed or relapsed MZL in need of treatment, who are not eligible or failed local therapy, following the assumption that this novel chemotherapy - free combination is significantly more effective than Rituximab single agent therapy and at least as efficient as Rituximab/chemotherapy, but avoids chemotherapy - related toxicity.