Study to Evaluate the Efficacy and Safety of Loncastuximab Tesirine in Patients With Relapsed or Refractory Diffuse Large B-Cell Lymphoma

This is a Phase 2, multi-center, open-label, single-arm study of the efficacy and safety of loncastuximab tesirine used as monotherapy in patients with relapsed or refractory DLBCL. The study will enroll approximately 140 patients Loncastuximab Tesirine is an antibody drug conjugate (ADC) composed of a humanized antibody directed against human cluster of differentiation 19 (CD19), stochastically conjugated through a cathepsin-cleavable linker to SG3199, a pyrrolobenzodiazepine (PBD) dimer cytotoxin. Loncastuximab tesirine has been designed to target and kill CD19-expressing malignant B-cells. A 2-stage design will be used in this clinical study, with an interim analysis for futility on the first 52 patients. If ≥10 patients respond (CR+PR), the study will proceed to complete full enrollment. Enrollment will continue during the interim analysis; however, further enrollment will be halted if futility is confirmed. For each patient, the study will include a Screening Period (of up to 28 days), a Treatment Period (cycles of 3 weeks), and a Follow-up Period (approximately every 12 week visits for up to 3 years after treatment discontinuation). Patients may continue treatment until disease progression, unacceptable toxicity, or other discontinuation criteria, whichever occurs first.