Study of Acalabrutinib and Tafasitamab in MZL Patients

Marginal zone B cell lymphomas (MZLs) comprise three distinct entities: extranodal MZL (EMZL) of mucosa-associated lymphoid tissue type (MALT) lymphoma, splenic MZL (SMZL) and nodal MZL (NMZL). Together they represent approximately 5%-15% of all non-Hodgkin lymphomas. MZL are in general indolent lymphomas with relatively low risk of transformation. The available treatment options can lead to responses but disease recurrence is often observed. For patients with MZL and recurrent disease following initial treatment, currently there is no established standard therapy and new treatment options and treatment combinations are needed. The proposed trial will evaluate the safety and efficacy of the anti-CD19 monoclonal antibody tafasitamab in combination with the BTK inhibitor acalabrutinib. The B-lymphocyte, lineage specific surface antigen CD19 is broadly and homogeneously expressed in MZLs. This makes CD19 an attractive target for the treatment of MZL patients, in particular those who failed a previous rituximab-containing regimen. On the other hand, genetic and immunogenetic data point to B-cell receptor signalling as a key oncogenic pathway of MZLs. The activity of single agent ibrutinib in MZLs is an in vivo proof that MZLs are addicted of BTK-driven signalling and that the BCR pathway is a vulnerability of these lymphomas. The safety profile of the anti CD19 monoclonal antibody tafasitamab and of the BTK inhibitor acalabrutinib indicate the possibility that their combination can be developed without major overlapping side effects. The proposed trial is a prospective multicenter trial combining tafasitamab and acalabrutinib in patients with MZL (including EMZL, SMZL and NMZL) with disease refractory to or in first or greater relapse after prior systemic therapy.