Schuster, Stephen J

CD19-directed CAR T-cells (CTL019) can produce durable remissions in chronic lymphocytic leukemia (CLL), but therapeutic success depends on whether autologous T-cells expand, persist, and retain cytotoxic function after manufacturing. Failure of CLL T-cells is often attributed to exhaustion, although many dysfunctional CLL T-cells retain inflammatory cytokine production. We tested whether this paradox reflects immunosenescence, an aging-like program defined by costimulatory loss, DNA damage, inflammatory secretion, repertoire restriction, and proliferative arrest. In response-linked preinfusion CTL019 products, nonresponders and short partial responders had higher senescence and senescence-associated secretory phenotype (SASP) programs than the functional-responder group, comprising complete responders and partial responders with transformed disease. These programs were detectable before infusion and became more prominent during manufacture in susceptible products. They tracked with weak in vivo CAR T-cell expansion and were associated with inferior survival. Serum proteomics revealed a circulating, CLL-associated SASP-like inflammatory milieu in nonresponders. Flow cytometry and T-cell receptor (TCR) profiling showed that poor responders carried CD27⁻CD28⁻ and KLRG1⁺ CD8 T-cells at apheresis, lower product CD27, and reduced product TCR diversity. Research-manufactured CAR T-cells from treatment-naïve CLL samples displayed the same state, most prominently in CD4 CAR T-cells, with SA-β-gal, p16, p53, DNA damage, depletion of less-differentiated states, and senescence-enriched transcriptomes. Under repeated CD19 stimulation, CLL-derived products reached a proliferative ceiling, and p53-high products lost cytotoxic reserve. Ibrutinib improved proliferative fitness, attenuated senescence-associated features and SASP output in paired patient and direct-exposure assays, and enhanced CAR T-cell expansion in an ibrutinib-resistant CLL model. Together, these data identify immunosenescence as a measurable and functionally consequential barrier to CAR T-cell efficacy in CLL and a candidate for therapeutic modulation.

Patients in the liso-cel plus ibrutinib cohort of the phase 1/2, open-label TRANSCEND CLL 004 study had relapsed/refractory chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and received liso-cel (50×106 [dose level (DL)1] or 100×106 [DL2] chimeric antigen receptor-positive T cells) with concurrent ibrutinib from enrollment through 90 days after liso-cel infusion or longer per investigator discretion. Primary end point was complete response/remission (CR)/CR with incomplete marrow recovery (CRi) by investigator assessment. Among 56 patients who received ibrutinib plus liso-cel (DL1, n=5; DL2, n=51), median (range) age was 64.5 years (44‒77), 98% had high-risk cytogenetics, 55% had progression on Bruton tyrosine kinase inhibitor and venetoclax failure, and median (range) number of prior therapies was 5 (1‒13). Median (range) follow-up was 24.8 months (3.1‒51.8). At DL2, CR/CRi rate was 45% (95% confidence interval [CI], 31‒60) and overall response rate was 86% (95% CI, 74‒94). Median (95% CI) duration of response was not reached (NR; 28.7‒NR) for patients with CR/CRi and 41.4 months (23.3‒NR) for all responders. Median (95% CI) progression-free survival was 31.4 months (20.1‒NR). In DL1+DL2, most common grade ≥3 treatment-emergent adverse events (TEAE) were neutropenia (52%) and anemia (41%). Cytokine release syndrome was reported in 80% of patients (grade 3, 4%; no grade 4/5), and neurological events in 41% (grade 3/4, 11%; no grade 5). Ibrutinib-related TEAEs were reported in 68% of patients (grade 3/4, 43%; no grade 5). Liso-cel plus ibrutinib demonstrated notable efficacy in patients with relapsed/refractory CLL/SLL with predictable and manageable safety. Clinicaltrials.gov: NCT03331198; NCT03435796.

Abstract The ELARA trial indicates tisagenlecleucel (tisa-cel) is an effective anti-CD19 chimeric antigen receptor T-cell therapy for relapsed or refractory follicular lymphoma (r/r FL). As ELARA is a single-arm trial, this study compares tisa-cel outcomes from the ELARA trial with usual care from a real-world cohort. ELARA enrolled 98 patients as of 29 March 2021 (median follow-up: 15 months from enrollment). Usual care data were obtained from ReCORD-FL, a global retrospective study of patients with r/r FL, who met similar eligibility criteria to ELARA. With a data cutoff date of 31 December 2020, 187 patients with ≥2 preceding treatment lines were included in the ReCORD-FL (median follow-up: 57 months from third-line) study. An indirect treatment comparison was performed for 97 patients from the ELARA trial and 143 patients from the ReCORD-FL study with no missing data on baseline factors. The line of therapy for which outcomes were assessed was selected or matched between cohorts using propensity score modeling. After baseline factor adjustment via weighting by odds, complete response rate (CRR; 95% confidence interval) was 69.1% (59.8%-78.3%) for tisa-cel vs. 37.3% (26.4%-48.3%) for usual care; overall response rate was 85.6% (78.7%-92.5%) vs. 63.6% (52.5%-74.7%). Kaplan-Meier probability of being progression/event-free at 12 months was 70.5% (61.4%-79.7%) for tisa-cel vs. 51.9% (40.6%-63.3%) for usual care, with hazard ratio (HR)=0.60 (0.34-0.86); 12-month overall survival was 96.6% (92.9%-100%) vs. 71.7% (61.2%-82.2%), with HR=0.2 (0.02-0.38). In conclusion, tisa-cel was associated with a 1.9-fold higher complete response rate and a 1.4-fold higher rate of being progression or event free at 12 months vs usual care, as well as a death risk reduction of 80%. The findings provide additional evidence on the benefit of tisa-cel in patients with r/r FL after ≥2 treatment lines. This trial was registered at www.clinicaltrials.gov as NCT03568461