Chimeric antigen receptor (CAR)-T cell therapies have improved the outcome for many patients with relapsed or refractory aggressive B-cell lymphomas. In 2017, axicabtagene ciloleucel and soon after tisagenlecleucel became the first approved CAR-T cell products for patients with high-grade B-cell lymphomas or diffuse large B-cell lymphoma (DLBCL) who are relapsed or refractory to ≥ 2 prior lines of therapy; lisocabtagene maraleucel was approved in 2021. Safety and efficacy outcomes from the pivotal trials of each CAR-T cell therapy have been reported. Despite addressing a common unmet need in the large B-cell lymphoma population and utilizing similar CAR technologies, there are differences between CAR-T cell products in manufacturing, pivotal clinical trial designs, and data reporting. Early reports of commercial use of axicabtagene ciloleucel and tisagenlecleucel provide the first opportunities to validate the impact of patient characteristics on the efficacy and safety of these CAR-T cell therapies in the real world. Going forward, caring for patients after CAR-T cell therapy will require strategies to monitor patients for sustained responses and potential long-term side effects. In this review, product attributes, protocol designs, and clinical outcomes of the key clinical trials are presented. We discuss recent data on patient characteristics, efficacy, and safety of patients treated with axicabtagene ciloleucel or tisagenlecleucel in the real world. Finally, we discuss postinfusion management and preview upcoming clinical trials of CAR-T cell therapies.

We analyzed 186 patients with lymphoma who underwent allogeneic stem cell transplantation (ASCT) with fludarabine-melphalan (FM) conditioning and different types of donors (25 haploidentical [HD], 98 matched unrelated [MUD], and 63 matched related [MRD]) at our institution between September 2009 and January 2018. Patients received fludarabine 160 mg/m² (40 mg/m²/day for 4 days) in combination with 1 dose of melphalan 140 mg/m² (FM140) or 100 mg/m² (FM100). Engraftment was similar among the 3 groups (92%, 89%, and 98%, respectively; P = .7). The 6-month cumulative incidence of grade III-IV acute graft-versus-host disease (GVHD) was 4% in the HD group, 14% in the MUD group, and 8% in the MRD group (P not significant), and the respective 3-year cumulative incidence of chronic GVHD was 5%, 16%, and 26% (P not significant). The respective 3-year nonrelapse mortality and relapse rates were 31%, 32%, and 10% (HD versus MUD, P = .9; HD versus MRD, P = .02) and 15%, 21%, and 39% (HD versus MUD, P = .4; HD versus MRD, P = .04). At 3 years, progression-free survival (PFS) was 59%, 44%, and 46% (P not significant); overall survival (OS) was 52%, 54%, and 67% (P not significant); and GVHD-free, relapse-free survival was 39%, 31%, and 24% (P not significant). No differences in the 3-year PFS (57% versus 43%; P = .3) and OS (64% versus 58%; P = .7) were seen between patients receiving FM100 and those receiving FM140. Our data demonstrate that in patients with lymphoma, ASCT with HD transplants have similar outcomes as ASCT with HLA-matched transplants, and the FM100 conditioning regimen appears to be at least as effective as the FM140 regimen.

Immunotherapy using T cells genetically engineered to express a chimeric antigen receptor (CAR) is rapidly emerging as a promising new treatment for haematological and non-haematological malignancies. CAR-T-cell therapy can induce rapid and durable clinical responses, but is associated with unique acute toxicities, which can be severe or even fatal. Cytokine-release syndrome (CRS), the most commonly observed toxicity, can range in severity from low-grade constitutional symptoms to a high-grade syndrome associated with life-threatening multiorgan dysfunction; rarely, severe CRS can evolve into fulminant haemophagocytic lymphohistiocytosis (HLH). Neurotoxicity, termed CAR-T-cell-related encephalopathy syndrome (CRES), is the second most-common adverse event, and can occur concurrently with or after CRS. Intensive monitoring and prompt management of toxicities is essential to minimize the morbidity and mortality associated with this potentially curative therapeutic approach; however, algorithms for accurate and consistent grading and management of the toxicities are lacking. To address this unmet need, we formed a CAR-T-cell-therapy-associated TOXicity (CARTOX) Working Group, comprising investigators from multiple institutions and medical disciplines who have experience in treating patients with various CAR-T-cell therapy products. Herein, we describe the multidisciplinary approach adopted at our institutions, and provide recommendations for monitoring, grading, and managing the acute toxicities that can occur in patients treated with CAR-T-cell therapy.

Purpose

Axicabtagene ciloleucel (axi-cel) is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell therapy approved for relapsed/refractory large B-cell lymphoma (LBCL) on the basis of the single-arm phase II ZUMA-1 trial, which showed best overall and complete response rates in infused patients of 83% and 58%, respectively. We report clinical outcomes with axi-cel in the standard-of-care (SOC) setting for the approved indication.

Patients and methods

Data were collected retrospectively from all patients with relapsed/refractory LBCL who underwent leukapheresis as of September 30, 2018, at 17 US institutions with the intent to receive SOC axi-cel. Toxicities were graded and managed according to each institution's guidelines. Responses were assessed as per Lugano 2014 classification.

Results

Of 298 patients who underwent leukapheresis, 275 (92%) received axi-cel therapy. Compared with the registrational ZUMA-1 trial, 129 patients (43%) in this SOC study would not have met ZUMA-1 eligibility criteria because of comorbidities at the time of leukapheresis. Among the axi-cel-treated patients, grade ≥ 3 cytokine release syndrome and neurotoxicity occurred in 7% and 31%, respectively. Nonrelapse mortality was 4.4%. Best overall and complete response rates in infused patients were 82% (95% CI, 77% to 86%) and 64% (95% CI, 58% to 69%), respectively. At a median follow-up of 12.9 months from the time of CAR T-cell infusion, median progression-free survival was 8.3 months (95% CI, 6.0 to15.1 months), and median overall survival was not reached. Patients with poor Eastern Cooperative Oncology Group performance status of 2-4 and elevated lactate dehydrogenase had shorter progression-free and overall survival on univariable and multivariable analysis.

Conclusion

The safety and efficacy of axi-cel in the SOC setting in patients with relapsed/refractory LBCL was comparable to the registrational ZUMA-1 trial.

Background

In a phase 1 trial, axicabtagene ciloleucel (axi-cel), an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, showed efficacy in patients with refractory large B-cell lymphoma after the failure of conventional therapy.

Methods

In this multicenter, phase 2 trial, we enrolled 111 patients with diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma, or transformed follicular lymphoma who had refractory disease despite undergoing recommended prior therapy. Patients received a target dose of 2×10⁶ anti-CD19 CAR T cells per kilogram of body weight after receiving a conditioning regimen of low-dose cyclophosphamide and fludarabine. The primary end point was the rate of objective response (calculated as the combined rates of complete response and partial response). Secondary end points included overall survival, safety, and biomarker assessments.

Results

Among the 111 patients who were enrolled, axi-cel was successfully manufactured for 110 (99%) and administered to 101 (91%). The objective response rate was 82%, and the complete response rate was 54%.With a median follow-up of 15.4 months, 42% of the patients continued to have a response, with 40% continuing to have a complete response. The overall rate of survival at 18 months was 52%. The most common adverse events of grade 3 or higher during treatment were neutropenia (in 78% of the patients), anemia (in 43%), and thrombocytopenia (in 38%). Grade 3 or higher cytokine release syndrome and neurologic events occurred in 13% and 28% of the patients, respectively. Three of the patients died during treatment. Higher CAR T-cell levels in blood were associated with response.

Conclusions

In this multicenter study, patients with refractory large B-cell lymphoma who received CAR T-cell therapy with axi-cel had high levels of durable response, with a safety profile that included myelosuppression, the cytokine release syndrome, and neurologic events. (Funded by Kite Pharma and the Leukemia and Lymphoma Society Therapy Acceleration Program; ZUMA-1 ClinicalTrials.gov number, NCT02348216 .).