Safety and Antitumor Activity Study of Loncastuximab Tesirine and Durvalumab in Diffuse Large B-Cell, Mantle Cell, or Follicular Lymphoma

This is a Phase 1b, open-label, single-arm combination study with a dose escalation phase (Part 1) followed by a dose expansion phase (Part 2). The study will enroll approximately 75 participants. A standard 3+3 dose escalation design will be used for Part 1. The DLT period will be the 21 days after the first durvalumab dose. Part 2 will consist of up to 3 expansion cohorts, one for DLBCL, one for MCL, and one for FL. Each cohort will be approximately 20 participants treated at the dose determined in Part 1. The study will include a Screening Period (of up to 28 days), a Treatment Period (cycles of 3, 6, and 4 weeks), and a Follow-up Period (approximately every 12 week visits for up to 2 years after treatment discontinuation).