Patients with relapsed/refractory acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) have poor outcomes compared with newly diagnosed, treatment-naïve patients. The phase 2, open-label DELPHINUS study evaluated daratumumab (16 mg/kg intravenously) plus backbone chemotherapy in children with relapsed/refractory B-cell ALL (n=7) after ≥2 relapses and children and young adults with T-cell ALL (children, n=24; young adults, n=5) or LL (n=10) after first relapse. The primary …