The efficacy of obinutuzumab is established in chronic lymphocytic leukemia and follicular lymphoma. Its role in less frequent B‐cell lymphomas is not yet clear. Rituximab monotherapy is an established first‐line treatment in splenic marginal zone lymphoma (SMZL), leading to excellent and long‐lasting remissions, with less than 10% of patients experiencing suboptimal responses. We here report the first two cases of rituximab‐refractory SMZL patients, responding to obinutuzumab monotherapy. They had previously received six weekly rituximab infusions at first line and experienced stable disease with persistent splenomegaly and extensive bone marrow infiltration. Obinutuzumab was administered for six weekly infusions as second‐line treatment. Both of them achieved durable complete responses with full restoration of cytopenias and complete resolution of splenomegaly and bone marrow infiltration. At the present follow‐up, they are still without any evidence of disease at 37 and 20 months posttreatment, respectively. Thus, obinutuzumab monotherapy represents a valuable therapeutic option in SMZL, especially for rituximab‐refractory patients, offering a time‐limited therapy compared to ibrutinib, sparing chemotherapy‐associated myelotoxicity, and splenectomy morbidity.
Angelopoulou et al. (Thu,) studied this question.