Kloos, Ioana

Abstract Brexucabtagene autoleucel (brexu-cel) is a chimeric antigen receptor T-cell therapy approved for relapsed/refractory mantle cell lymphoma (R/R MCL). Here, we report real-world effectiveness and safety outcomes of brexu-cel in a prospective study of patients with R/R MCL, including subgroups based on prior treatment with Bruton's tyrosine kinase inhibitor, bendamustine, or autologous hematopoietic cell transplant (auto-HCT) and number of prior therapy lines, using Center for International Blood and Marrow Transplant Research registry data. A total of 476 patients with R/R MCL who received brexu-cel between July 2020 and December 2022 were included in the analysis. With a median follow-up of 13.5 months, the overall response rate was 91% and complete response rate was 82%. One-year overall survival and progression-free survival rates were 76% and 63%, respectively. One-year cumulative incidence of nonrelapse mortality was 8%. Prior auto-HCT was associated with better duration of response within 6 months after infusion (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.28-0.85) but greater risk of immune effector cell–associated neurotoxicity syndrome (odds ratio [OR], 1.66; 95% CI, 1.06-2.60). Prior bendamustine was associated with increased risk of prolonged thrombocytopenia (OR, 1.90; 95% CI, 1.13-3.21). In patients with 1 to 2 prior therapy lines, relapse or progression was less frequent compared with those with ≥3 prior lines (HR, 0.64; 95% CI, 0.42-1.00). Collectively, our results suggest that real-world outcomes with brexu-cel were consistent with those of the ZUMA-2 trial, regardless of prior therapy type or number of prior therapy lines.

ZUMA-12 is a multicenter phase 2 study evaluating axicabtagene ciloleucel (axi-cel) autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy as part of first-line treatment for high-risk large B-cell lymphoma (LBCL). In the primary efficacy analysis (n = 37; median follow-up, 15.9 months), axi-cel demonstrated a high rate of complete responses (CR; 78%) and a safety profile consistent with prior experience. Here, we assessed updated outcomes from ZUMA-12 in 40 treated patients after ≥3 years of follow-up. Eligible adults underwent leukapheresis, lymphodepleting chemotherapy, and axi-cel infusion (2 × 106 CAR T cells/kg). Investigator-assessed CR, objective response, survival, safety, and CAR T-cell expansion were assessed. The CR rate among response-evaluable patients (n = 37) increased after the primary analysis to 86% (95% confidence interval [CI], 71%-95%), with a 92% objective response rate. After a median follow-up of 47.0 months (range, 37.1-57.8 months), 36-month estimates (95% CI) of duration of response and event-free, progression-free, and overall survival were 81.8% (63.9%-91.4%), 73.0% (55.6%-84.4%), 75.1% (57.5%-86.2%), and 81.1% (64.4%-90.5%), respectively. In total, 4 patients had new malignancies, 2 occurring after the data cutoff of the primary analysis; none were axi-cel–related. Eight patients died on study, 2 of whom died from nonrelapse mortality causes. After long-term follow-up, axi-cel demonstrated a high durable response rate, with no new safety signals after the primary analysis, suggestive of an effective first-line therapy with curative intent in high-risk LBCL. Further assessments are needed to determine its benefit vs standard of care. This trial was registered at clinicaltrials.gov, as NCT03761056.

Introduction: Brexu-cel is an autologous anti-CD19 CAR T-cell therapy approved in the US and EU for treatment of adults with R/R MCL (after ≥2 prior therapies in EU) based on a high objective response rate (ORR; 93%; 67% complete response [CR] rate) in pts who received the pivotal dose (2×106 anti-CD19 CAR T cells/kg; Cohort 1; N=60) in ZUMA-2 (NCT02601313; Wang et al, N Engl J Med 2020). After ~4 years (y) of median follow-up, Brexu-cel demonstrated a median overall survival (OS) of 46.4 months (mo) in 68 pts with R/R MCL in Cohort 1 (Goy et al. ASH 2023). Cohort 2 was established to assess a lower dose (0.5 x 106 anti-CD19 CAR T cells/kg); however, the risk/benefit ratio of the Cohort 1 dose was deemed the optimal dose before Cohort 2 reached full enrollment. Here we report primary outcomes of Cohort 2 and 5-y outcomes of Cohorts 1 and 2. Methods: Pts with R/R MCL and ≤5 prior therapies including a BTKi received optional bridging therapy (protocol-defined), lymphodepleting chemotherapy, and 1 infusion of brexu-cel. The primary endpoint was ORR (CR + partial response [PR]) per Lugano classification (Cheson et al. J Clin Oncol. 2014) by independent radiology review committee (IRRC) assessment. Key secondary endpoints were duration of response (DOR), best objective response (BOR), progression-free survival (PFS), OS, and safety. After ≥24 mo of assessment, pts could transition to long-term follow-up (LTFU), NCT05041309, where they were monitored for late-onset targeted/serious adverse events (AEs) possibly related to brexu-cel, presence of replication-competent retrovirus (RCR), and/or insertional mutagenesis. Descriptive statistics are reported herein. Results: As of the primary analysis data cutoff date, July 24, 2019, 17 pts enrolled in Cohort 2, 14 (82%) of whom were treated with brexu-cel with median follow-up of 16.0 mo (range, 13.9-18.0). Pt characteristics for Cohort 2 (N=14) were similar to Cohort 1; median (range) age and number or prior therapies was 61.5 y (52-73) and 3 (2-5); 100% US-treated, 79% male, 71% extranodal disease, 50% intermediate or high s-MIPI scores, 50% refractory to last therapy, and 43% had prior autologous stem cell transplantation. ORR was 93% (95% CI, 66.1-99.8) per IRRC; 64% had a CR (95% CI, 35.1-87.2), 29% had a PR (95% CI, 8.4-58.1) and 1 pt was not assessed. All 14 pts had ≥1 AE of any grade (Gr), with Gr ≥3 AEs occurring in 93% of pts; the most common being hypotension (50%), white blood cell count decrease (50%), anemia (43%), and neutrophil count decrease (43%). Rates of Gr ≥3 cytokine release syndrome (CRS) and neurological events were 7% and 43%, respectively. As of April 1, 2024, median follow-up (range) for Cohort 1 and 2 was 67.8 mo (58.2-88.6; N=68) and 72.3 mo (70.1-74.3; N=14), respectively. In Cohort 1, 24 pts were still alive (35%; 2 withdrew consent and 1 lost to follow up) and 44 pts died (65%). In Cohort 2, 8 pts were still alive (57%; 2 withdrew consent and 1 lost to follow up) and 6 pts died (43%). A total of 27 pts (Cohort 1, n=23; Cohort 2, n=4) enrolled in the LTFU study by data cutoff with a median follow-up time of 70.2 mo (range, 58.2-88.6). Median (95% CI) investigator-assessed DOR and PFS were 36.5 mo (17.7-48.9; n=60; 17 patients in ongoing response, all CR) and 25.3 mo (12.7-46.6; N=68) in Cohort 1; and 57.5 mo (4.7-not estimable [NE]; n=12; 3 pts in ongoing response, all CR) and 29.5 mo (3.3-NE; N=14) in Cohort 2. Median OS (95% CI) and 60-mo OS rates (95% CI) were 46.5 mo (24.9- 60.2) and 38.5% (26.7-50.1) in Cohort 1; and not reached (9.4-NE) and 53.6% (23.8-76.2) in Cohort 2. One pt had 3 ongoing AEs on LTFU, hypogammaglobulinemia and 2 viral infections that arose prior to LTFU. Two pts died on LTFU, both due to progressive disease; no new secondary malignancies or RCR cases were reported. Conclusions: Consistent with Cohort 1, brexu-cel demonstrated a high ORR, durable responses, and an expected safety profile in pts with R/R MCL in Cohort 2 despite the lower dose. However, small sample size limits interpretation of these results. With >5 y of median follow-up, pts in Cohort 1 and 2 continued to experience durable responses with high 60-mo OS rates. No new safety signals were detected and no secondary malignancies or RCR cases were reported in LTFU. Additionally, ZUMA-2 results are consistent with real-world outcomes of brexu-cel in the post BTKi R/R MCL setting (89% ORR and 81% CR rate; Wang Y, et al. J Clin Oncol. 2023). These results support the continued use of brexu-cel in R/R MCL.

Background: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for the treatment of relapsed/refractory (R/R) LBCL. ZUMA-12 (NCT03761056) is a Phase 2, multicenter, single-arm study of axi-cel as part of first-line treatment in patients with high-risk LBCL. In the primary efficacy analysis (n=37; median follow-up of 15.9 months), axi-cel demonstrated a high rate of investigator-assessed complete response (CR; 78%; 95% CI, 62-90) and an 89% objective response rate (ORR; 95% CI, 75-97). Axi-cel also had a manageable safety profile, with no new safety signals observed in the first-line setting (Neelapu et al. Nat Med. 2022). Here, we report updated efficacy and safety outcomes from ZUMA-12 in all patients treated with axi-cel after a median follow-up of ≥40 months. Methods: Eligible adults had high-risk LBCL, with MYC and BCL2 and/or BCL6 rearrangements (double- or triple-hit histology) per investigator or an International Prognostic Index (IPI) score ≥3, plus a positive interim PET per Lugano classification (Deauville score 4/5) after 2 cycles of an anti-CD20 monoclonal antibody and anthracycline-containing regimen. Patients underwent leukapheresis, followed by lymphodepleting chemotherapy (cyclophosphamide and fludarabine) on Days -5, -4, and -3, and a single axi-cel infusion of 2×10 6 CAR T cells/kg on Day 0. Per investigator discretion, non-chemotherapy bridging could be administered. The primary endpoint was investigator-assessed CR rate per Lugano classification (Cheson et al. J Clin Oncol. 2014). Secondary endpoints included ORR, duration of response (DOR), event-free survival (EFS), progression-free survival (PFS), overall survival (OS), safety, and levels of CAR T cells in blood and cytokines in serum. Results: As of May 3, 2023, 42 patients were enrolled and 40 were treated with axi-cel, with a median follow-up of 40.9 months (range, 29.5-50.2). In total, 37 patients were evaluable for response (centrally confirmed double- or triple-hit histology or IPI score ≥3). The CR rate was 86% (95% CI, 71-95), and 92% (95% CI, 78-98) of patients had an objective response. Patients with centrally confirmed double- or triple-hit histology (n=10) had a CR rate of 90%. Responses were ongoing in 73% of response-evaluable patients at data cutoff. Medians for DOR, EFS, PFS, and OS were not reached. The 36-month estimates for DOR, EFS (Figure 1), PFS, and OS (Figure 2) were 82%, 73%, 75%, and 81%, respectively. All treated patients (n=40) experienced adverse events (AEs) of any grade and 88% of patients had grade ≥3 AEs. Similar to the primary analysis, the most common any-grade AEs were pyrexia (100%), headache (70%), and neutrophil count decreased (55%). No new cases of cytokine release syndrome (CRS) or neurologic events of any grade occurred since the prior data cut and all cases of CRS and neurologic events reported were resolved by data cutoff. Prolonged cytopenias of any grade (present Day ≥30 post-infusion) occurred in 9 patients (n=7 neutrophil count decreased) and were resolved by data cutoff. There were 8 deaths due to progressive disease (n=5) and other causes not related to axi-cel (1 COVID-19, 1 esophageal adenocarcinoma, 1 septic shock on Days 350, 535, and 287 post axi-cel infusion, respectively). Two of the 8 deaths (1 progressive disease and 1 esophageal adenocarcinoma) occurred after the primary analysis. Among treated patients, post-infusion CAR T-cell expansion by peak and area under the curve was 36.9 cells/µL and 368.0 cells/µL×days, respectively, in those with ongoing responses at data cutoff (n=17), 45.1 cells/µL and 413.4 cells/µL×days in those who relapsed (n=6), and 34.7 cells/µL and 566.8 cells/µL×days in non-responders (n=3). Conclusion: In this updated analysis of ZUMA-12 with a median follow-up of ≥40 months, axi-cel demonstrated a high rate of durable responses and no new safety signals. Axi-cel may benefit patients exposed to fewer prior therapies and those with high-risk LBCL, a population with high unmet need and poor outcomes after standard first-line chemoimmunotherapy.