Highlights
- Tisagenlecleucel induces high overall response rates (52%) with durable complete remissions in relapsed/refractory diffuse large B-cell lymphoma (DLBCL).
- Five-year follow-up from the JULIET trial demonstrates a relapse-free probability of 61% among responders, underscoring sustained efficacy.
- Response and survival correlate with baseline prognostic factors such as International Prognostic Index risk factors, lactate dehydrogenase, and C-reactive protein levels.
- Adverse events including cytokine release syndrome and neurotoxicity are generally manageable, with no new long-term safety signals reported.
Background
Diffuse large B-cell lymphoma (DLBCL) represents the most common aggressive non-Hodgkin lymphoma subtype. Patients who are refractory to frontline and second-line therapies or relapse following autologous hematopoietic stem-cell transplantation (HSCT) historically face poor prognoses, with limited curative options. Chimeric antigen receptor T-cell (CAR T-cell) therapy has emerged as a novel and promising immunotherapeutic strategy. Tisagenlecleucel is an autologous anti-CD19 CAR T-cell therapy designed to target CD19-expressing B cells, leading to their eradication. Initial clinical data from single-center and phase 2a studies suggested substantial efficacy in B-cell malignancies, motivating larger pivotal trials.
Key Content
Chronological Development and Pivotal Trials
The international, multicenter, phase 2 JULIET trial (NCT02445248) was conducted to evaluate the efficacy and safety of tisagenlecleucel in adult patients with relapsed or refractory DLBCL, especially those ineligible for or with disease progression after HSCT. The study enrolled 93 infused patients with refractory disease to evaluate response rates and safety outcomes. The median follow-up was 14 months at initial reporting.
Study Population and Intervention
Eligible patients included adults with relapsed or refractory DLBCL, including variants such as transformed follicular lymphoma and high-grade B-cell lymphoma, who had exhausted standard therapeutic options or were ineligible for auto-HSCT. Patients underwent leukapheresis for autologous CAR T-cell manufacturing followed by lymphodepleting chemotherapy before infusion of tisagenlecleucel.
Efficacy Outcomes
The primary endpoint of best overall response rate (ORR), defined by independent review committee assessments, was 52% (95% CI, 41 to 62), with 40% achieving complete response (CR) and 12% partial response (PR). Responses were observed consistently across various prognostic subgroups, including patients with adverse baseline features. Twelve months post initial response, relapse-free survival was 65% overall and 79% among those achieving a complete response, indicating durable remissions.
Five-Year Follow-Up Findings
The recently published 5-year analysis from the JULIET trial, involving 115 infused patients with a median follow-up of 74.3 months, revealed sustained remission and survival benefits. The median duration of response was not reached, and the 5-year relapse-free probability among responders was 61%. Progression-free survival (PFS) at 60 months was 28%, while overall survival (OS) was 32% for all treated patients and 56% for responders.
Baseline characteristics such as fewer International Prognostic Index (IPI) risk factors (<2), lower disease stage (I/II), lower lactate dehydrogenase (LDH) levels, and lower C-reactive protein (CRP) levels correlated with improved long-term outcomes. Notably, patients with relapsed rather than refractory disease, and those requiring fewer bridging therapies prior to infusion, showed higher likelihood of response.
Safety Profile and Adverse Events
Common grade 3 or 4 adverse events of special interest in the initial JULIET study included cytokine release syndrome (CRS) in 22% of patients, neurologic events in 12%, prolonged cytopenias (>28 days) in 32%, infections in 20%, and febrile neutropenia in 14%. Importantly, no deaths were attributed directly to tisagenlecleucel, CRS, or cerebral edema. The 5-year follow-up confirmed the absence of new safety concerns and no secondary T-cell malignancies emerged. Safety remained manageable with established supportive care protocols.
Molecular and Translational Insights
Exploratory analyses showed no significant differences in tumor CD19 expression or immune checkpoint-related protein profiles between responders and non-responders, suggesting broad applicability of tisagenlecleucel independent of these biomarkers. These findings support the robustness of CD19 as a therapeutic target, although ongoing research continues to investigate potential resistance mechanisms and biomarkers predicting durability of response.
Expert Commentary
Tisagenlecleucel represents a major advancement in the management of relapsed or refractory DLBCL, a patient population with historically dismal outcomes. The JULIET trial’s robust response and survival data, sustained over five years, provide compelling evidence supporting tisagenlecleucel’s potential curative capacity in a subset of patients.
The safety profile, notably the manageable incidence and severity of CRS and neurotoxicity, aligns with that observed in other CD19-directed CAR T-cell therapies. Early recognition and treatment strategies have minimized morbidity and mortality associated with these toxicities.
Baseline prognostic markers such as IPI, LDH, and CRP aid in patient stratification and risk assessment, enabling optimization of treatment sequencing. Such factors may guide clinical decisions for bridging therapies and patient selection, although prospective validation is needed.
Limitations include the single-arm design without direct comparator arms, challenging cross-trial comparisons with other CAR T products, and the need for broader real-world data across diverse healthcare settings. Furthermore, mechanisms of relapse post-CAR T-cell therapy and strategies to overcome them remain active research areas.
Ongoing investigations focus on combination therapies, timing of CAR T-cell infusion, and approaches to enhance CAR T-cell persistence. Integration with checkpoint inhibitors or novel agents may further improve outcomes.
Conclusion
The JULIET trial has established tisagenlecleucel as an effective and durable treatment modality for adult patients with relapsed or refractory diffuse large B-cell lymphoma ineligible for or relapsed after stem-cell transplantation. Five-year data highlight long-term remission and survival benefits with a manageable safety profile, reinforcing tisagenlecleucel’s role as a potentially curative option. Future research should optimize patient selection, elucidate resistance mechanisms, and explore combinatorial strategies to expand the therapeutic impact of CAR T-cell therapy in aggressive B-cell lymphomas.
References
- Schuster SJ, Bishop MR, Tam CS, et al. Tisagenlecleucel in Adult Relapsed or Refractory Diffuse Large B-Cell Lymphoma. N Engl J Med. 2019;380(1):45-56. doi:10.1056/NEJMoa1804980. PMID: 30501490.
- Maziarz RT, Bishop MR, Tam CS, et al. Five-Year Analysis of the JULIET Trial of Tisagenlecleucel in Patients With Relapsed/Refractory Large B-Cell Lymphoma. J Clin Oncol. 2025 Nov 18;JCO2500507. doi:10.1200/JCO-25-00507. PMID: 41252666.
