Stephens, Deborah M.

7501 Background: In patients (pts) with R/R CLL/SLL that progressed on BTKi and failed venetoclax (ven)-based regimens, achieving CR with current treatment is uncommon. New therapies that achieve deep and durable responses are needed. We report the primary analysis of the phase 1/2, single-arm, multicenter TRANSCEND CLL 004 (NCT03331198) study evaluating liso-cel in pts with R/R CLL/SLL. Methods: Pts must have received at least 2 prior lines of therapy, including a BTKi. Eligible pts received liso-cel at a target dose of either 50 (DL1) or 100 (DL2) × 106 CAR+ T cells. The primary endpoint was rate of CR and CR with incomplete marrow recovery (CRi) by IRC per 2018 iwCLL criteria in the prespecified subset of efficacy-evaluable pts with disease progression on BTKi and ven failure (primary efficacy analysis set [PEAS]) at DL2 (null hypothesis [H0]: ≤ 5%). Key secondary endpoints were ORR (H0: ≤ 40%) and rate of undetectable minimal residual disease (uMRD; 10−4) in blood (H0: ≤ 5%). Results: Of 137 leukapheresed pts, 117 received liso-cel (safety set), 96 (DL1 = 9; DL2 = 87) were efficacy evaluable, and 53 (DL1 = 4; DL2 = 49) were in the PEAS. In the safety set, median (range) age was 65 y (49–82), 83% had high-risk features, median (range) lines of prior therapy was 5 (2–12), and all pts had prior BTKi. Median (range) on-study follow-up was 21.1 mo (0.4–55.6) for the safety set. In the PEAS at DL2, the primary endpoint of CR/CRi rate was met at 18.4% (95% CI, 8.8–32.0; 1-sided P = 0.0006; Table). ORR was 42.9% and was not statistically significant (95% CI, 28.8–57.8; 1-sided P = 0.3931). The uMRD rate was 63.3% in blood and 59.2% in marrow. Median (95% CI) DOR was 35.3 mo (11.01–not reached [NR]) with a median follow-up of 19.7 mo. Median duration of CR/CRi was NR. In the safety set, rate of any-grade CRS was 84.6% (gr 3, 8.5%; no gr 4/5) and neurological events (NE) was 45.3% (gr 3, 17.9%; gr 4, 0.9%; no gr 5); 69.2% received tocilizumab and/or corticosteroids for CRS/NEs. Rate of gr ≥ 3 infections, hypogammaglobulinemia, and prolonged cytopenia was 17.1%, 15.4%, and 53.8%, respectively. One death related to liso-cel was due to hemophagocytic lymphohistiocytosis. Liso-cel exhibited rapid in vivo expansion and was detected by qPCR in blood up to 36 mo after infusion. Conclusions: Liso-cel demonstrated durable CR/CRi, high uMRD rates, and a manageable safety profile in pts with heavily pretreated, high-risk R/R CLL/SLL and high unmet need. Clinical trial information: NCT03331198 . [Table: see text]

AbstractCheckpoint inhibitor (CPI) therapy with anti–PD-1 antibodies has been associated with mixed outcomes in small cohorts of patients with relapsed aggressive B-cell lymphomas after CAR-T failure. To define CPI therapy efficacy more definitively in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 US academic centers. Most patients (53%) had diffuse large B-cell lymphoma, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 vs 51 days) and OS (387 vs 131 days) were significantly longer in patients with late (>180 days) vs early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of patients treated with CPI. Most patients (83%) died, commonly because of progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of patients with aggressive B-cell lymphoma treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post–CAR-T outcomes.