Stem cell boost for immune effector cell associated hematotoxicity in multiple myeloma: minimizing long-term...

Cytopenia is one of the most common adverse events after BCMA chimeric antigen receptor (CAR) T cell therapy in the treatment of relapsed multiple myeloma (MM). The term Immune Effector Cell Associated Hematotoxicity (ICAHT) was coined to describe the unique hematological toxicities following novel CAR T cell therapies. The management of prolonged ICAHT ( > 30 days) is quite challenging, and patients have high incidences of infections, require prolonged transfusion support and have an increased non-relapse mortality. Stem cell boost (SCB) leads to prompt and durable count recovery and can minimize long-term complications while enabling therapeutic options in the post CAR T-cell therapy relapse setting.

Herein we review current data on ICAHT, determine how SCB can lead to improved outcomes, and offer a view on future applications of SCB. The database 'pubmed' was searched for the terms 'CAR-T,' 'ICAHT', and 'Stem Cell', and results as well as selected citations were used for the present study.

SCB for prolonged ICAHT improves morbidity and potentially mortality. Future use of SCB will depend on the long-term outcomes of CAR-T cell therapy in earlier treatment lines. For patients with high likelihood of ICAHT, prophylactive stem cell collection should be considered.