A Study to Evaluate the Tolerability, Safety, Pharmacokinetics, and Antitumor Activity of Loncastuximab Tesirine in Combination With Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone (R-CHOP) in Participants With Previously Untreated Diffuse Large B-cell Lymphoma (LOTIS-8)

This is a Phase 1b, open-label, multi-center study in participants with previously untreated DLBCL, with a dose escalation part followed by dose expansion part. Participants will be treated by loncastuximab tesirine in combination with R CHOP. The duration of the study participation for each participant is defined as the time from the date of signed written informed consent to the completion of the follow-up period, withdrawal of consent, lost to follow-up, or death, whichever occurs first. The study will include a Screening Period (of up to 28 days), a Treatment Period of 6 cycles (cycles of 3 weeks), and a Follow-up Period (approximately every 12 week visits) for up to approximately 3 years from end-of-treatment (EOT).