Background: Century Therapeutics’ foundational technology is built on induced pluripotent stem cells, differentiated from allogeneic approaches that utilize non-renewable donor-derived cells. This approach allows production of a clonal cell bank of precisely edited cells that can be expanded and differentiated to supply large amounts of homogeneous allogeneic therapeutic products for off-the-shelf use. CNTY-101 is an allogeneic Chimeric Antigen Receptor NK (CAR-NK) cell product with genetic modifications designed to specifically target CD19-expressing B-cell malignancies, reduce allorejection in the recipient allowing for repeat dosing, increase persistence, and enable cell elimination in the event of unexpected adverse events. CNTY-101, as a CAR-NK product, has the potential for improved safety over T-cell based cellular therapies. Methods: This first-in-human study will determine the MTD and recommended Phase 2 regimen (RP2R) of CNTY-101 in combination with subcutaneous (SC) IL-2 in patients with R/R aggressive and indolent CD19-positive B-cell Non-Hodgkin lymphomas including diffuse large B-cell lymphoma, mantle cell lymphoma, primary mediastinal large B-cell lymphoma, follicular lymphoma and marginal zone lymphoma, who are without other treatment options. Part 1 of the study (dose escalation using the BOIN design) will start with a dose of CNTY-101 cells without IL-2 (1 to 3 subjects), followed by dose escalation up to four dose cohorts administering a single dose of CNTY-101 cells in combination with IL-2 daily for 8 days (Sched A). After the single-dose MTD (or the maximal single dose) has been reached, a fractionated schedule of 3 doses per 28-day cycle, administered on Days 1, 8, and 15 (Sched B), will also be explored, starting with approximately one-third the maximum single dose level of CNTY-101, followed by escalation/de-escalation. Subjects in whom CNTY-101 shows signs of clinical benefit (i.e. stable disease or better per Lugano 2014 criteria) may receive additional cycles of CNTY-101 if the Investigator, Sponsor, and appropriate regulatory authorities, as required, concur that the benefit-risk is positive. One overall CNTY-101 RP2R will be declared in Part 1. Part 2, expansion, will further evaluate the safety, pharmacokinetics (PK), and efficacy of the CNTY-101 regimen, treating up to an additional 12 subjects to reach a total of approximately 20 subjects treated at the RP2R. In addition to safety and efficacy endpoints, the trial will evaluate exploratory PK, immunogenicity and pharmacodynamic endpoints including evaluations of tumor cfDNA, iNK tumor trafficking and serum cytokines. Clinical trial information: NCT05336409.