In Waldenström's macroglobulinemia (WM) conventional chemotherapy induces only low complete remission (CR) rates and responses of short duration compared to other indolent lymphomas. Thus innovative approaches are needed which combine excellent activity and tolerability in patients with WM, who are mostly of advanced age. Today, chemotherapy in combination with the anti-cluster of differentiation (CD) 20 antibody rituximab is still the backbone of treatment in patients with WM and is recommended as first line in national and international treatment guidelines. With the approval of Ibrutinib by the European Medicines Agency (EMA) 2015 for patients with relapsed WM or for patients not eligible for chemotherapy with treatment naïve WM treatment landscape has changed in this lymphoma subtype and there is an urgent need to evaluate to which extent chemotherapy-free approaches add clinical benefit to the patient. The treatment in the European Consortium for Waldenström's Macroglobulinemia (ECWM)-2 trial will test, whether the chemotherapy-free approach, which is given orally (ibrutinib) and subcutaneously (bortezomib and rituximab from cycle 2 onwards) (B-RI) will approach the efficacy of chemotherapy containing treatment concepts, but avoids chemotherapy associated toxicity. From the perspective of single agent ibrutinib, this regimen tests whether ibrutinib can be further optimized by adding rituximab and bortezomib. The combination of rituximab and ibrutinib was tested in comparison to rituximab/placebo in a large international phase III trial on behalf of the European Consortium for Waldenström's Macroglobulinemia in relapsed and first line WM, and results were recently published: in this trial no unexpected toxicity of the combination ibrutinib/rituximab was reported. Furthermore, ibrutinib/rituximab was significantly superior to rituximab/placebo with regard to response rates and PFS. From the perspective of the established rituximab/bortezomib regimen, the combination of B-RI will evaluate whether adding ibrutinib to this combination will add any benefit for the patient.~To this end, the aim of the study is to assess the toxicity and efficacy of B-RI in an exploratory phase II trial.
In Waldenström macroglobulinemia (WM) conventional chemotherapy induces only low complete remission (CR) rates and responses of short duration compared to other indolent lymphomas. Thus innovative approaches are needed which combine excellent activity and tolerability in patients with WM, who are mostly of advanced age. The immunochemotherapy DRC (dexamethasone, rituximab, cyclophosphamide) was shown to be highly effective in patients with WM without inducing major hematological toxicities. On the other hand the proteasome inhibitor bortezomib showed substantial activity as a single agent in WM with only very few side effects when given in a weekly schedule. Recent data confirmed high activity with low toxicity for ibrutinib in relapsed WM patients as single agent therapy. Based on these observations it is the aim of this study to investigate the efficacy and toxicity of the chemotherapy-free combination bortezomib, rituximab, ibrutinib (B-RI) in treatment naïve WM patient.