Background: Patients (pts) with aggressive large B-cell NHL who are R/R after first-line immunochemotherapy and not eligible for high-dose chemotherapy and HSCT have a poor prognosis and no established standard of care. The ongoing, open-label phase 2 PILOT study is the first to assess the safety and efficacy of liso-cel, an investigational, CD19-directed, defined composition, 4-1BB CAR T cell product infused at equal target doses of CD8+ and CD4+ CAR+ T cells, as 2L therapy in TNE pts (NCT03483103). Methods: Eligible pts had aggressive R/R diffuse large B-cell lymphoma NOS (de novo or transformed follicular lymphoma [FL]), high-grade B-cell lymphoma, or FL grade 3B with 1 line of prior therapy containing an anthracycline and anti-CD20 agent. Pts were deemed TNE by meeting ≥1 criteria: age ≥70 y, ECOG PS 2, or impaired organ function (DLCO ≤60% [but SaO₂≥92% and CTCAE ≤1 dyspnea], LVEF ≥40% to < 50%, creatinine clearance > 30 to < 60 mL/min, or AST/ALT > 2 to ≤5 × ULN). Liso-cel (100 × 10⁶ CAR+ T cells) was administered 2–7 days after lymphodepletion (LD) with fludarabine/cyclophosphamide. The primary endpoint is ORR; key secondary endpoints are AEs and CR rate. Results: At data cutoff, 25 pts had LD followed by liso-cel infusion. Pt characteristics are summarized in the Table. Overall, 48% (n = 12) had high tumor burden and 48% were primary refractory. 18/25 (72%) pts had grade ≥3 treatment-emergent AEs, 40% of which were cytopenias. No grade 5 AEs occurred within the first 30 days after liso-cel. Five pts (20%) had cytokine release syndrome (CRS) and 3 (12%) had neurological events (NEs). No grade 3/4 CRS was observed; 2 pts (8%) had grade 3/4 NEs. Five pts (20%) received tocilizumab and/or dexamethasone for CRS/NEs. At a median follow-up of 3.5 mo, the ORR was 80% (95% CI, 59–93; n = 20); 48% of pts (n = 12) achieved CR. Conclusions: These interim data suggest that elderly and/or comorbid pts with R/R aggressive large B-cell NHL, who are not eligible for high-dose chemotherapy and HSCT, can receive 2L liso-cel with similar safety and efficacy to 3L+ pts as previously reported (Abramson, ASH 2019 #241). Updated data with longer follow-up will be presented. Clinical trial information: NCT03483103.