MDS AS A CAUSE FOR PROLONGED HEMATOLOGIC TOXICITY AFTER TREATMENT WITH CD19 TARGETED CAR-T CELL THERAPY IN PATIENTS WITH RELAPSED REFRACTORY LYMPHOMA

Myelodysplastic Syndrome After Anti-CD19 Chimeric Antigen Receptor T-cell Therapy: A Case Series

The utility of CD19-targeted chimeric antigen receptor T-cell (CAR-T cell) therapy in the management of refractory/relapsed B-cell malignancies has increased tremendously in recent times. In addition to cytokine release syndrome (CRS), neurotoxicity, and infections, CAR-T cell patients develop cytopenias, with about 15% of the patients continuing to have severe cytopenias up to three months after treatment. Retrospective reviews have reported the development of myelodysplastic syndrome (MDS) in patients undergoing CAR-T cell therapy. Here, we describe four cases of MDS and/or clonal cytopenias of undetermined significance (CCUS), developing after CAR-T cell therapy. A retrospective review of four patients with relapsed/refractory B-cell lymphomas treated with CD19-directed autologous CAR-T cell was conducted at our institution. The median age was 72.5 years (range 63-76). Three of the four patients had double-hit diffuse large B-cell lymphoma (DLBCL). The median number of lines of therapy before CAR-T cell was three. Only one patient had a prior autologous stem cell transplant (ASCT). The median time to diagnosis of MDS/CCUS from CAR-T cell therapy was three months. Two cases of CCUS diagnosed were at one- and two-month post-CAR-T cell, and two cases of MDS were diagnosed at 10 and 26 months. None of the patients had dysplastic clones before the initiation of CAR-T cell therapy. Only one patient was found to have CCUS-developed CRS post-CAR-T cell requiring treatment with tocilizumab and steroids. Three patients showed complete response, with one showing a very good partial response. All the patients were in remission with no additional therapies post-CAR-T cell. One patient died secondary to COVID-19-related complications. Four patients with prolonged cytopenias were found to have either MDS or CCUS after CAR-T cell therapy. Two CCUS cases underwent bone marrow evaluation early in the course of cytopenias and may develop into MDS, acute myeloid leukemia (AML), or myeloproliferative neoplasm over time. Our retrospective case series review, compared to previous studies, constitutes of patients with no prior clonal hematopoiesis-related cytogenetic abnormalities, fewer lines of therapy, and only one patient with previous hematopoietic stem cell transplantation (HSCT). Based on the upcoming data and our review, a bone marrow biopsy with next-generation sequencing (NGS) is imperative in patients with prolonged cytopenias after CAR-T cell therapy. A diagnosis of CCUS/MDS in these cases can help guide treatment.

Beyond the storm - subacute toxicities and late effects in children receiving CAR T cells

As clinical advances with chimeric antigen receptor (CAR) T cells are increasingly described and the potential for extending their therapeutic benefit grows, optimizing the implementation of this therapeutic modality is imperative. The recognition and management of cytokine release syndrome (CRS) marked a milestone in this field; however, beyond the understanding gained in treating CRS, a host of additional toxicities and/or potential late effects of CAR T cell therapy warrant further investigation. A multicentre initiative involving experts in paediatric cell therapy, supportive care and/or study of late effects from cancer and haematopoietic stem cell transplantation was convened to facilitate the comprehensive study of extended CAR T cell-mediated toxicities and establish a framework for new systematic investigations of CAR T cell-related adverse events. Together, this group identified six key focus areas: extended monitoring of neurotoxicity and neurocognitive function, psychosocial considerations, infection and immune reconstitution, other end organ toxicities, evaluation of subsequent neoplasms, and strategies to optimize remission durability. Herein, we present the current understanding, gaps in knowledge and future directions of research addressing these CAR T cell-related outcomes. This systematic framework to study extended toxicities and optimization strategies will facilitate the translation of acquired experience and knowledge for optimal application of CAR T cell therapies.