CD19 and acute lymphoblastic leukemia: In February 2021, the anti-CD19 CAR therapy ARI-0001, classified as an ‘Advanced Therapy Medicinal Product’ (ATMP), received authorization from the Spanish Agency of Medicines and Medical Devices under a ‘hospital exemption’ for treating adult patients (>25 years old) with relapsed/refractory (R/R) B-ALL [17].