Anti-CD19-directed chimeric antigen receptor (CAR) T-cell therapy has had a resounding effect on the treatment of chemotherapy-insensitive aggressive B-cell non-Hodgkin lymphoma (B-NHL). There are ...now two US Food and Drug Administration (FDA)-approved products available for treating these patients, and a third product is expected to be approved in the coming months. The question remains: Is there a preferred or best product for my patient? However, answering that question is more complicated than simply balancing the reported efficacy and toxicity results.
This review outlines potential confounding factors involving the three products and their pivotal clinical trials and highlights additional considerations of manufacturing reliability and overall cost that must be considered when weighing one product against another. It will also review the directions in which the field is moving and strategies being examined to improve efficacy as well as toxicity.
Because a randomized three-arm clinical trial is unlikely, a product may have to be chosen on the basis of results from treatment centers that have experience with all three products. But by the time those results are available, they are likely to be outdated because, given the rapid evolution of the field, the next product will probably have been identified.
Abstract
Chimeric antigen receptor (CAR) T-cell therapy is a revolutionary new form of immunotherapy for the treatment of hematologic malignancies. The two primary toxicities associated with CAR ...T-cell therapy include cytokine-release syndrome and neurotoxicity. Cytokine-release syndrome is generally self-limited but high-grade toxicities like hypotension and hypoxemia can be managed with agents that block the effects of IL-6, like tocilizumab, and/or corticosteroids. Although CAR T-cell therapy–associated neurotoxicity is a well-described clinical phenomenon, its pathophysiology remains inadequately understood; treatments and preventive strategies remain elusive. Animal models and clinical trial experience suggest the centrality of monocytes, endothelial dysfunction, and the blood-brain barrier in the development of CAR T-cell–associated neurotoxicity. Here we report what is known from preclinical models, clinical trials, and histopathologic studies regarding the pathophysiology of neurotoxicity, predictors of its incidence, and potential targets for the treatment and prevention of neurotoxicity.
Most patients with advanced-stage indolent non-Hodgkin lymphoma have multiple relapses. We assessed axicabtagene ciloleucel autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy in ...relapsed or refractory indolent non-Hodgkin lymphoma.
ZUMA-5 is a single-arm, multicentre, phase 2 trial being conducted at 15 medical cancer centres in the USA and two medical cancer centres in France. Patients were eligible if they were aged 18 years or older, with histologically confirmed indolent non-Hodgkin lymphoma (follicular lymphoma or marginal zone lymphoma), had relapsed or refractory disease, previously had two or more lines of therapy (including an anti-CD20 monoclonal antibody with an alkylating agent), and an Eastern Cooperative Oncology Group performance score of 0 or 1. Patients underwent leukapheresis and received conditioning chemotherapy (cyclophosphamide at 500 mg/m2 per day and fludarabine at 30 mg/m2 per day on days −5, −4, and −3) followed by a single infusion of axicabtagene ciloleucel (2 × 106 CAR T cells per kg) on day 0. The primary endpoint was overall response rate (complete response and partial response) assessed by an independent review committee per Lugano classification. The primary activity analysis was done after at least 80 treated patients with follicular lymphoma had been followed up for at least 12 months after the first response assessment at week 4 after infusion. The primary analyses were done in the per-protocol population (ie, eligible patients with follicular lymphoma who had 12 months of follow-up after the first response assessment and eligible patients with marginal zone lymphoma who had at least 4 weeks of follow-up after infusion of axicabtagene ciloleucel). Safety analyses were done in patients who received an infusion of axicabtagene ciloleucel. This study is registered with ClinicalTrials.gov, NCT03105336, and is closed to accrual.
Between June 20, 2017, and July 16, 2020, 153 patients were enrolled and underwent leukapheresis, and axicabtagene ciloleucel was successfully manufactured for all enrolled patients. As of data cutoff (Sept 14, 2020), 148 patients had received an infusion of axicabtagene ciloleucel (124 84% who had follicular lymphoma and 24 16% who had marginal zone lymphoma). The median follow-up for the primary analysis was 17·5 months (IQR 14·1–22·6). Among patients who were eligible for the primary analysis (n=104, of whom 84 had follicular lymphoma and 20 had marginal zone lymphoma), 96 (92%; 95% CI 85–97) had an overall response and 77 (74%) had a complete response. The most common grade 3 or worse adverse events were cytopenias (104 70% of 148 patients) and infections (26 18%). Grade 3 or worse cytokine release syndrome occurred in ten (7%) patients and grade 3 or 4 neurological events occurred in 28 (19%) patients. Serious adverse events (any grade) occurred in 74 (50%) patients. Deaths due to adverse events occurred in four (3%) patients, one of which was deemed to be treatment-related (multisystem organ failure).
Axicabtagene ciloleucel showed high rates of durable responses and had a manageable safety profile in patients with relapsed or refractory indolent non-Hodgkin lymphoma.
Kite, a Gilead Company
Axicabtagene ciloleucel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy. In the previous analysis of the ZUMA-1 registrational study, with a median follow-up of 15·4 months ...(IQR 13·7–17·3), 89 (82%) of 108 assessable patients with refractory large B-cell lymphoma treated with axicabtagene ciloleucel achieved an objective response, and complete responses were noted in 63 (58%) patients. Here we report long-term activity and safety outcomes of the ZUMA-1 study.
ZUMA-1 is a single-arm, multicentre, registrational trial at 22 sites in the USA and Israel. Eligible patients were aged 18 years or older, and had histologically confirmed large B-cell lymphoma—including diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma, and transformed follicular lymphoma—according to the 2008 WHO Classification of Tumors of Hematopoietic and Lymphoid Tissue; refractory disease or relapsed after autologous stem-cell transplantation; an Eastern Cooperative Oncology Group performance status of 0 or 1; and had previously received an anti-CD20 monoclonal antibody containing-regimen and an anthracycline-containing chemotherapy. Participants received one dose of axicabtagene ciloleucel on day 0 at a target dose of 2 × 106 CAR T cells per kg of bodyweight after conditioning chemotherapy with intravenous fludarabine (30 mg/m2 body-surface area) and cyclophosphamide (500 mg/m2 body-surface area) on days −5, −4, and −3. The primary endpoints were safety for phase 1 and the proportion of patients achieving an objective response for phase 2, and key secondary endpoints were overall survival, progression-free survival, and duration of response. Pre-planned activity and safety analyses were done per protocol. ZUMA-1 is registered with ClinicalTrials.gov, number NCT02348216. Although the registrational cohorts are closed, the trial remains open, and recruitment to extension cohorts with alternative endpoints is underway.
Between May 19, 2015, and Sept 15, 2016, 119 patients were enrolled and 108 received axicabtagene ciloleucel across phases 1 and 2. As of the cutoff date of Aug 11, 2018, 101 patients assessable for activity in phase 2 were followed up for a median of 27·1 months (IQR 25·7–28·8), 84 (83%) had an objective response, and 59 (58%) had a complete response. The median duration of response was 11·1 months (4·2–not estimable). The median overall survival was not reached (12·8–not estimable), and the median progression-free survival was 5·9 months (95% CI 3·3–15·0). 52 (48%) of 108 patients assessable for safety in phases 1 and 2 had grade 3 or worse serious adverse events. Grade 3 or worse cytokine release syndrome occurred in 12 (11%) patients, and grade 3 or worse neurological events in 35 (32%). Since the previous analysis at 1 year, additional serious adverse events were reported in four patients (grade 3 mental status changes, grade 4 myelodysplastic syndrome, grade 3 lung infection, and two episodes of grade 3 bacteraemia), none of which were judged to be treatment related. Two treatment-related deaths (due to haemophagocytic lymphohistiocytosis and cardiac arrest) were previously reported, but no new treatment-related deaths occurred during the additional follow-up.
These 2-year follow-up data from ZUMA-1 suggest that axicabtagene ciloleucel can induce durable responses and a median overall survival of greater than 2 years, and has a manageable long-term safety profile in patients with relapsed or refractory large B-cell lymphoma.
Kite and the Leukemia & Lymphoma Society Therapy Acceleration Program.
Axicabtagene ciloleucel is the first U.S. Food and Drug Administration–approved autologous anti‐CD19 chimeric antigen receptor (CAR) T‐cell therapy for the treatment of patients with relapsed or ...refractory large B‐cell lymphoma after ≥2 prior systemic therapies. Although axicabtagene ciloleucel is administered only at authorized treatment centers, community oncologists play a critical role in the CAR T‐cell treatment journey, recognizing potentially eligible patients for referral and then, after treatment, closely collaborating with treatment centers to monitor and manage patients long term. ZUMA‐1, the pivotal, multicenter, phase I/II study of 108 patients treated with axicabtagene ciloleucel, resulted in an objective response rate of 83%, including 58% complete responses. With a 27.1‐month median follow‐up, 39% of patients had ongoing responses. CAR T‐cell therapy is associated with the potentially life‐threatening adverse events (AEs) of cytokine release syndrome and neurologic events, which generally occur early after treatment. In ZUMA‐1, cytokine release syndrome and neurologic events were generally reversible and grade ≥3 cytokine release syndrome and neurologic events occurred in 11% and 32% of patients, respectively. Frequent prolonged AEs included hypogammaglobulinemia, B‐cell aplasia, and cytopenias requiring supportive care until recovery of hematopoietic function. Rate of treatment‐related mortality was low, at <2%. With appropriate management of common AEs, axicabtagene ciloleucel offers the potential for long‐term durable responses in patients who otherwise lack curative treatment options.
Implications for Practice
Community oncologists should be familiar with key aspects of chimeric antigen receptor (CAR) T‐cell indications and eligibility to help recognize and refer potential patients for this paradigm‐changing treatment option at the appropriate time during the disease course. To ensure optimal long‐term outcomes for patients who have been treated with CAR T‐cell therapy, oncologists must also be familiar with common prolonged AEs and their monitoring and management.
This article reviews information relevant to oncologists who are caring for patients who have been treated with CAR T cells or who are considering referring a patient with large B‐cell lymphoma for CAR T‐cell therapy.
Axicabtagene ciloleucel (axi-cel) was approved by the Food and Drug Administration for relapsed aggressive B-cell non-Hodgkin lymphoma in part on the basis of durable remission rates of approximately ...40% in a clinical trial population. Whether this efficacy, and the rates of toxicity, would be consistent in a postcommercial setting, with relaxed eligibility criteria and bridging therapy, is unknown. This study describes the efficacy and safety correlates and outcomes in this setting.
One hundred twenty-two patients from 7 medical centers in the United States were treated with axi-cel and were included in a modified intent-to-treat (mITT) analysis. Seventy-six patients (62%) were ineligible for the ZUMA-1 trial. Response and toxicity rates, duration of response (DOR), survival, and covariates are described on the basis of the mITT population. Correlative studies on blood and tumor samples were performed to investigate potential biomarkers of response and resistance.
Median follow-up was 10.4 months. In the mITT population, the best overall and complete response (CR) rates were 70% and 50%, respectively. Median DOR and progression-free survival (PFS) were 11.0 and 4.5 months in all patients and were not reached (NR) in CR patients. Median overall survival (OS) was NR; 1-year OS was 67% (95% CI, 59% to 77%). Although response rates were similar in the ZUMA-1-eligible and ZUMA-1-ineligible groups (70%
68%), there was a statistically significant improvement in CR rate (63%
42%,
= .016), DOR (median, NR
5.0 months;
= .014), PFS (median, NR
3.3 months;
= .020), and OS (1-year OS, 89%
54%;
< .001) in patients who were ZUMA-1 eligible. Rates of grade ≥ 3 cytokine release syndrome and neurotoxicty were 16% and 35%, respectively.
Axi-cel yields similar rates of overall response and toxicity in commercial and trial settings, although CR rates and DOR were more favorable in patients eligible for ZUMA-1.
Idelalisib is a small-molecule inhibitor of PI3Kδ with demonstrated efficacy for the treatment of relapsed/refractory chronic lymphocytic leukemia (CLL). To evaluate idelalisib as front-line therapy, ...we enrolled 24 subjects in a phase 2 study consisting of 2 months of idelalisib monotherapy followed by 6 months of combination therapy with idelalisib and the anti-CD20 antibody ofatumumab. After a median follow-up period of 14.7 months, hepatotoxicity was found to be a frequent and often severe adverse event. A total of 19 subjects (79%) experienced either grade ≥1 ALT or AST elevation during the study, and 13 subjects (54%) experienced grade ≥3 transaminitis. The median time to development of transaminitis was 28 days, occurring before ofatumumab introduction. Younger age and mutated immunoglobulin heavy chain status were significant risk factors for the development of hepatotoxicity. Multiple lines of evidence suggest that this hepatotoxicity was immune mediated. A lymphocytic infiltrate was seen on liver biopsy specimens taken from 2 subjects with transaminitis, and levels of the proinflammatory cytokines CCL-3 and CCL-4 were higher in subjects experiencing hepatotoxicity. All cases of transaminitis resolved either by holding the drug, initiating immunosuppressants, or both, and rates of recurrent toxicity were lower in patients taking steroids when idelalisib was reinitiated. A decrease in peripheral blood regulatory T cells was seen in patients experiencing toxicity on therapy, which is consistent with an immune-mediated mechanism. These results suggest that caution should be taken as drugs within this class are developed for CLL, particularly in younger patients who have not received prior disease-specific therapy. This study was registered at www.clinicaltrials.gov as #NCT02135133.
•Idelalisib as upfront therapy for CLL caused an early hepatotoxicity in a subset of primarily younger patients with IGHV-mutated disease.•Multiple lines of evidence suggest that this adverse effect is immune mediated, perhaps through inhibition of regulatory T cells.
ZUMA-1 demonstrated a high rate of durable response and a manageable safety profile with axicabtagene ciloleucel (axi-cel), an anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, in patients ...with refractory large B-cell lymphoma. As previously reported, prespecified clinical covariates for secondary end point analysis were not clearly predictive of efficacy; these included Eastern Cooperative Oncology Group performance status (0 vs 1), age, disease subtype, disease stage, and International Prognostic Index score. We interrogated covariates included in the statistical analysis plan and an extensive panel of biomarkers according to an expanded translational biomarker plan. Univariable and multivariable analyses indicated that rapid CAR T-cell expansion commensurate with pretreatment tumor burden (influenced by product T-cell fitness), the number of CD8 and CCR7+CD45RA+ T cells infused, and host systemic inflammation, were the most significant determining factors for durable response. Key parameters differentially associated with clinical efficacy and toxicities, with both theoretical and practical implications for optimizing CAR T-cell therapy. This trial was registered at www.clinicaltrials.gov as #NCT02348216.
•Axi-cel durable responses were associated with low baseline tumor burden, low systemic inflammation, and high product CCR7+CD45RA+ T cells.•Distinct sets of factors associated with durable response, grade ≥3 cytokine release syndrome, and grade ≥3 neurologic events.
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Brexucabtagene autoleucel (KTE-X19) autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy is approved for the treatment of relapsed/refractory mantle cell lymphoma (MCL). Outcomes after ...a 3-year follow-up in the pivotal ZUMA-2 study of KTE-X19 in relapsed/refractory MCL are reported, including for subgroups by prior therapy (bendamustine and type of Bruton tyrosine kinase inhibitor BTKi) or high-risk characteristics.
Patients with relapsed/refractory MCL (one to five prior therapies, including prior BTKi exposure) received a single infusion of KTE-X19 (2 × 10
CAR T cells/kg).
After a median follow-up of 35.6 months, the objective response rate among all 68 treated patients was 91% (95% CI, 81.8 to 96.7) with 68% complete responses (95% CI, 55.2 to 78.5); medians for duration of response, progression-free survival, and overall survival were 28.2 months (95% CI, 13.5 to 47.1), 25.8 months (95% CI, 9.6 to 47.6), and 46.6 months (95% CI, 24.9 to not estimable), respectively. Post hoc analyses showed that objective response rates and ongoing response rates were consistent among prespecified subgroups by prior BTKi exposure or high-risk characteristics. In an exploratory analysis, patients with prior bendamustine benefited from KTE-X19, but showed a trend toward attenuated T-cell functionality, with more impact of bendamustine given within 6 versus 12 months of leukapheresis. Late-onset toxicities were infrequent; only 3% of treatment-emergent adverse events of interest in ZUMA-2 occurred during this longer follow-up period. Translational assessments revealed associations with long-term benefits of KTE-X19 including high-peak CAR T-cell expansion in responders and the predictive value of minimal residual disease for relapse.
These data, representing the longest follow-up of CAR T-cell therapy in patients with MCL to date, suggest that KTE-X19 induced durable long-term responses with manageable safety in patients with relapsed/refractory MCL and may also benefit those with high-risk characteristics.
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