A Clinical Study of ONCT-808 in Subjects With Relapsed or Refractory B-Cell Malignancies

Key Inclusion Criteria: * Over 18 years old * Histologically confirmed aggressive B-cell NHL, including: * MCL, with diagnosis confirmed by cyclin D1 overexpression or evidence of t (11;14) translocation * LBCL, including: * DLBCL NOS * Primary mediastinal LBCL * High-grade BCL * DLBCL arising from follicular lymphoma * Follicular lymphoma grade 3B * Richter's syndrome * Availability of archival tissue for immunohistology, or willing to undergo baseline biopsy if not available * R/R with no available therapy. Subject must have: * Received prior systemic therapy that has included an alkylating agent, anthracycline, and an anti-CD20 mAb * Received and progressed after autologous hematopoietic stem cell transplant (HSCT) or is ineligible for or has refused to receive HSCT * Received prior approved CD19 CAR T-cell therapy or is ineligible for or has refused CD19 CAR-T * Minimum washout period between previous systemic therapy and leukapheresis includes: * Chemotherapy: at least 14 days or 5 half-lives, whichever is shorter * Autologous HSCT: at least 3 months * CD19 CAR T-cell therapy: at least 6 months * ≥1 measurable lesion per Lugano criteria (Cheson, 2014) * Subject has Fluorodeoxyglucose (FDG)-avid disease. * Subject has an ECOG performance status of 0 or 1. * Subject has adequate organ function: * ALC ≥100/uL * ANC ≥1000/uL (≥500/uL if due to lymphoma; growth factors allowed) * Hgb ≥8 g/dL (transfusion allowed) * Platelets ≥75,000/uL (≥50,000/uL if due to lymphoma; transfusion allowed) * CrCL ≥50 ml/min; AST/ALT ≤2.5x ULN, T. bili ≤1.5 mg/dl (except Gilbert's) * EF ≥50% by ECHO/MUGA; NCS ECG, NCS pleural effusion; O2 sat \>92% * Subject has an estimated life expectancy of \>12 weeks Key Exclusion Criteria: * Prior ROR1-targeted therapy * Current or anticipated systemic immunosuppressive therapy (e.g., prednisone \>5 mg) from LD chemo until Day 28 post ONCT-808 dosing * If receiving anticoagulation therapy, subject is unable to hold therapy for 3 days prior and 28 days following ONCT-808 administration * Known CNS involvement by malignancy within 6 months * H/o or current CNS disorder (e.g., seizure, CVA, dementia, cerebellar disease, cerebral edema, posterior reversible encephalopathy syndrome or any autoimmune disease with CNS involvement) within 6 months of study entry * Clinically significant cardiovascular disease (e.g., MI, UA, CABG, or CHF grade ≥2 NYHA within 12 months of planned ONCT-808 dosing) or serious arrhythmia requiring medication * Evidence of HIV infection or active HBV, HCV * Systemic fungal infection requiring medication in the last 12 months * H/o Covid-19 infection with residual lung infiltrate/fibrosis * H/o other malignancy except non-melanoma skin cancer or carcinoma in situ not in remission for ≥2 years * H/o autoimmune disease resulting in end organ injury or require systemic immunosuppression within last 2 years * H/o allogeneic HSCT or organ transplant