Acquired bone marrow aplasia and long-lasting complete remission with Loncastuximab Tesirine in a patient with transformed marginal zone lymphoma: a case report

Marginal zone lymphomas (MZL) are indolent lymphomas that may undergo transformation into aggressive lymphomas, most frequently diffuse large B-cell lymphoma (DLBCL). Loncastuximab tesirine (LONCA) is an antibody-drug conjugate used in the treatment of relapsed/refractory large B-cell lymphomas. Here we present the clinical case of a patient with nodal transformed DLBCL and concomitant bone marrow involvement by indolent lymphoma successfully treated with LONCA. However the therapy was discontinued after six cycles as the patient developed treatment-related bone marrow aplasia. This case raises concerns about prolonged hematologic toxicity of LONCA, particularly in patients with pre-existing marrow involvement while highlights the potential of this drug to induce deep and durable response, even after limited exposure.