ABSTRACT
Introduction: Patients with relapsed or refractory malignant lymphoma (rrNHL) after chemoimmunotherapy often do not experience longterm disease control. Therefore, novel therapeutic options are urgently needed. CD19, a type I transmembrane glycoprotein widely expressed in B-cell-lymphomas, has raised interest as a therapeutic target. Tafasitamab (formerly MOR208) is a humanized Fc-modified cytolytic CD19 antibody which exerts its efficacy via enhanced antibody-dependent cell-mediated cytotoxicity and antibody-dependent cellular phagocytosis, as well as direct cytotoxic effects on tumor cells. In a phase IIa study of tafasitamab in rrNHL patients and no curative option available, the antitumor activity and safety of tafasitamab was investigated. Patients received tafasitamab at a dose of 12mg/kg intravenously, weekly for 8 weeks. Treatment could be continued for additional 4 weeks when at least stable disease was reached. Patients who reached PR or CR after 12 weeks of treatment could extend their treatment until progression. Clinical outcome was promising, however the median follow-up was only 26 months and therefore, little is known about the long-term tolerability and safety of tafasitamab. Methods: We identified 5 patients from the database with rrNHL, namely FL, MZL and DLBCL, who are treated with single-agent tafasitamab for more than 5 years and performed a long-term analysis of its tolerability and safety. Only patients, for whom complete information was available concerning efficacy and toxicity and who consented for long-term evaluation of data, were selected. Results: Besides the ongoing long-term response, a very favorable safety profile was found. There were only a couple of non-severe adverse events (AEs) mostly within the first 2 years of treatment. Most common AEs were infections (45%) and neurological symptoms (14%). There were no grade 4 AEs or grade 4 late toxicities, only one episode of treatment-emergent hematological grade 3 AE and grade 3 dizziness, no late toxicities, or infusion related reactions. ECOG performance status was unimpaired. Discussion: Our data support the safety of the long-term use. Given the long-term tolerability of tafasitamab, it can be considered as a safe agent in combination with chemotherapy, kinase inhibitors, bispecific antibodies, EZH2-inhibitors, or other options. In a future project, we will analyse the response to Covid-19 vaccination in these patients.