A Phase 1 Open-Label Study to Evaluate the Safety and Antitumor Activity of Loncastuximab Tesirine and Durvalumab in Patients With Advanced Diffuse Large B-Cell Lymphoma, Mantle Cell Lymphoma, or Follicular Lymphoma

• Male or female participants aged 18 years or older

• Pathologic diagnosis of DLBCL, MCL, or FL

• Participants must have relapsed or refractory disease and have failed or been intolerant to standard therapy

• Participants who have received previous CD19-directed therapy must have a biopsy that shows CD19 expression after completion of the CD19-directed therapy

• Measurable disease as defined by the 2014 Lugano Classification

• Participants must be willing to undergo tumor biopsy

• ECOG performance status 0-1

• Screening laboratory values within the following parameters:

∙ Absolute neutrophil count (ANC) ≥1.0 × 103/µL (off growth factors at least 72 hours)

‣ Platelet count ≥75 × 103/µL without transfusion in the past 7 days

‣ Hemoglobin ≥9.0 g/dL (5.59 mmol/L), transfusion allowed

‣ Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and GGT ≤2.5 × the upper limit of normal (ULN)

‣ Total bilirubin ≤1.5 × ULN (participants with known Gilbert's syndrome may have a total bilirubin up to ≤3 × ULN)

‣ Blood creatinine ≤1.5 × ULN or calculated creatinine clearance ≥60 mL/min by the Cockcroft-Gault equation

• Negative beta-human chorionic gonadotropin (β-HCG) pregnancy test within 3 days prior to start of study drug on C1D1 for women of childbearing potential

⁃ Women of childbearing potential must agree to use a highly effective method of contraception from the time of giving informed consent until at least 16 weeks after the last dose of study therapy. Men with female partners who are of childbearing potential must agree that they will use a highly effective method of contraception from the time of giving informed consent until at least 16 weeks after the patient receives his last dose of study therapy