Outcomes of Anti-CD19 CAR-T Treatment of Pediatric B-ALL with Bone Marrow and Extramedullary Relapse

Overcoming the challenges of primary resistance and relapse after CAR-T cell therapy

INTRODUCTION

While CAR T-cell therapy has led to remarkable responses in relapsed B-cell hematologic malignancies, only 50% of patients ultimately have a complete, sustained response. Understanding the mechanisms of resistance and relapse after CAR T-cell therapy is crucial to future development and improving outcomes.

AREAS COVERED

We review reasons for both primary resistance and relapse after CAR T-cell therapies. Reasons for primary failure include CAR T-cell manufacturing problems, suboptimal fitness of autologous T-cells themselves, and intrinsic features of the underlying cancer and tumor microenvironment. Relapse after initial response to CAR T-cell therapy may be antigen-positive, due to CAR T-cell exhaustion or limited persistence, or antigen-negative, due to antigen-modulation on the target cells. Finally, we discuss ongoing efforts to overcome resistance to CAR T-cell therapy with enhanced CAR constructs, manufacturing methods, alternate cell types, combinatorial strategies, and optimization of both pre-infusion conditioning regimens and post-infusion consolidative strategies.

EXPERT OPINION

There is a continued need for novel approaches to CAR T-cell therapy for both hematologic and solid malignancies to obtain sustained remissions. Opportunities for improvement include development of new targets, optimally combining existing CAR T-cell therapies, and defining the role for adjunctive immune modulators and stem cell transplant in enhancing long-term survival.

Incidence of CD19-negative relapse after CD19-targeted immunotherapy in R/R BCP acute lymphoblastic leukemia: a review

There are inconsistencies in the reporting of CD19 antigen status following treatment with CD19-targeted therapies. A majority of evidence comes from studies reporting small sample sizes. In this review, we systematically summarize published studies that have reported rates of CD19-negative relapse after treatment with either blinatumomab or CD19-directed CAR T-cell therapy and report the rates of CD19-negative relapse when evaluated in a standardized way across trials. CD19-negative relapse appears to occur more commonly in relapses following CAR T-cell therapy compared with blinatumomab, whether proportions are calculated among all treated patients (8.7% vs 4.5%) or among patients who relapse (30% vs 22.5%). The median (range) duration of follow-up was 29.3 (17.4-50.8) and 20.4 (6.9-49.0) months for publications on blinatumomab (n = 10) and CAR T-cell therapies (n = 23), respectively. There is a need for standardized reporting of CD19 antigen status in the setting of relapse following novel immunotherapies to inform clinical practice.

Difference in Efficacy and Safety of Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy Containing 4-1BB and CD28 Co-Stimulatory Domains for B-Cell Acute Lymphoblastic Leukemia

This study quantified the differences in the efficacy and safety of different stimulation domains of anti-CD19 chimeric antigen receptor (CAR) T therapy for B-cell acute lymphoblastic leukemia (B-ALL). Clinical trials related to anti-CD19 CAR T-cell therapy for B-ALL were searched in public databases from database inception to 13 November 2021. The differences in overall survival (OS) and progression-free survival (PFS) of B-ALL patients treated with anti-CAR T-cell therapy containing 4-1BB and CD28 co-stimulatory domains were compared by establishing a parametric survival function. The overall remission rate (ORR), the proportion of people with minimal residual disease (MRD)-negative complete remission (CR), the incidence of cytokine release syndrome (CRS), and the neurotoxicity across different co-stimulatory domains was assessed using a random-effects model. The correlation between the ORR, MRD-negative CR, PFS, and OS was tested. The results showed that the median OS of anti-CAR T-cell treatment containing 4-1BB and CD28 co-stimulatory domains was 15.0 months (95% CI: 11.0-20.0) and 8.5 months (95% CI: 5.0-14.0), and the median PFS was 7.0 months (95% CI: 4.0-11.5) and 3.0 months (95% CI: 1.5-7.0), respectively. Anti-CD19 CAR T-cells in the 4-1BB co-stimulatory domain showed superior benefits in patients who achieved ORR. The incidence of neurotoxicity was significantly higher in the CD28 co-stimulatory domain of anti-CD19 CAR T-cells than in the 4-1BB co-stimulatory domain. In addition, the ORR and MRD-negative CR were strongly correlated with OS and PFS, and PFS and OS were strongly correlated. The 4-1BB co-stimulatory domain suggested a better benefit-risk ratio than the CD28 co-stimulatory domain in B-ALL.

Umbilical cord blood: A promising source for allogeneic CAR-T cells

Chimeric antigen receptor T (CAR-T) cell therapy is an effective treatment for relapsed and refractory acute lymphoblastic leukemia (R/R ALL). However, autologous CAR-T cells derived from patients with B-ALL often show poor amplification ability, exhaustion, and anergy. To overcome these limitations, allogeneic CAR-T cells may be used as effective substitutes; however, which source would be the best substitute is unclear. In this study, we compared the immunophenotype and antitumor efficacy of anti-CD19 CAR-T cells derived from healthy donor cord blood (CB), healthy donor peripheral blood (PB), and PB of B-ALL patients [PB (patient)] in vitro and NOD-Prkdcem26cd52Il2rgem26Cd22/Nju (NCG)-immunodeficient mice, respectively. The results revealed that CAR-T cells derived from healthy donor CB and PB showed a higher proportion of naive T cells and longer tumor suppression in tumor-bearing mice than those of PB (patient). PB (patient) CAR-T cells had a higher proportion of regulatory T cells (Treg cells) and released high levels of interluekin-10 (IL-10), which also suggest a poor prognosis. Thus, CAR-T cells derived from healthy donors have better antitumor efficacy than CAR-T cells derived from PB (patient), and CB may be a good source of allogeneic CAR-T cells.

Results of ARI-0001 CART19 cell therapy in patients with relapsed/refractory CD19-positive acute lymphoblastic leukemia with isolated extramedullary disease

We evaluated outcomes of 18 patients with isolated extramedullary disease (iEMD) relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) treated with the CD19-directed CAR T cells ARI-0001 in two centers (adult and pediatric), including patients treated in the CART19-BE-01 trial and the consecutive compassionate use program. iEMD was detected by PET-CT in 78% (14/18), and/or by cerebrospinal fluid analysis in 28% (5/18). Patients received cyclophosphamide and fludarabine followed by 1 × 10⁶ ARI-0001 cells/kg, initially as a single dose (first patient) and later split into three fractions (10%, 30%, and 60%). Cytokine release syndrome (CRS) occurred in 50% (9/18) of patients, with no cases of grade ≥3 CRS, and 1 case (6%) of grade 1 neurotoxicity. Tocilizumab was used in 6% of patients (1/18). Procedure-related mortality was 0% at 2 years. Objective responses were seen in 94% (95% confidence interval [CI]: 73%-99%) of patients, with complete responses (CR) seen in 78% (95% CI: 52%-94%) of them. Progression-free and overall survival were 49% (95% CI: 30%-79%) and 61% (95% CI: 40%-92%) at 2 years. In conclusion, the use of ARI-0001 cells in patients with R/R ALL and iEMD was associated with a safety and efficacy profile that is comparable with what is observed in patients with marrow involvement and in line with other CART19 products.

Efficacy and safety of CD19 CAR-T cell therapy for patients with B cell acute lymphoblastic leukemia involving extramedullary relapse

OBJECTIVE

To evaluate the efficacy and safety of CD19 chimeric antigen receptor (CAR) T cell therapy for patients with B cell acute lymphoblastic leukemia (B-ALL) involving extramedullary relapse.

METHODS

Fifteen patients with B-ALL involving extramedullary relapse who received CD19 CAR-T cell therapy in the First Affiliated Hospital, Zhejiang University School of Medicine from January 2016 to October 2021 were enrolled in this study. The overall survival and leukemia-free survival of patients were analyzed using Kaplan-Meier curves, and the response of extramedullary lesions in different locations following the CD19 CAR-T cell therapy was observed. Cytokine release syndrome (CRS), hematological toxicity, and immune effector cell-associated neurotoxicity syndrome (ICANS) during CD19 CAR-T cell therapy were analyzed.

RESULTS

The median follow-up time was 7 (3-71) months, and 11 cases (73.3%) achieved complete response, median duration of complete response was 6 (2-27) months; 3 cases (20.0%) achieved partial response; 1 case (6.7%) got progressive disease. The overall response rate was 93.3% (14/15), and the overall survival rate was 80.0% (12/15) at the end of follow-up. The cumulative incidence of relapse was 40.0% (6/15) and relapse mortality rate was 20.0% (3/15). Until last follow-up date, 9 cases (60.0%) were still in disease-free survival. Among the 15 patients, 13 cases (86.7%) developed cytokine release syndrome (CRS) after cell infusion, including 7 cases with grade 1-2 CRS, 6 cases with grade 3 CRS; 1 case suffered from reversible ICANS; 15 cases (100.0%) developed B cell dysplasia; 12 cases (80.0%) developed severe hematologic adverse reactions; 2 cases (13.3%) had abnormal liver function; 1 case (6.7%) had abnormal renal function; 4 cases (26.7%) developed infection. The adverse reactions mentioned above were well controlled.

CONCLUSION

CD19 CAR-T cell therapy shows explicit efficacy and controllable adverse reactions for B-ALL patients with extramedullary relapse.

Cumulative triglyceride-glucose index is a risk for CVD: a prospective cohort study

Background

Previous studies has shown a significant relationship between baseline triglyceride-glucose (TyG) index and cardiovascular disease (CVD). However, the long-term effect of TyG index and incident CVD remains uncertain. This study aimed to investigate the association between cumulative TyG index and the risk of CVD.

Method

In this study, we recruited individuals participating in Kailuan Study from 2006 to 2013 without stroke, myocardial infarction, and cancer in the four consecutive examinations. Cumulative TyG index was calculated by multiplying the average TyG index and the time between the two consecutive examinations. Cumulative TyG index levels were categorized into four quartile groups: Q1 group, ≤ 50.65 (as reference group), Q2 group, 50.65–53.86, Q3 group, 53.86–57.44, Q4 group, > 57.44. The association between cumulative TyG index and the risk of CVD was estimated by multivariable Cox proportional hazard models.

Result

A total of 44,064 individuals participated in the final analysis. After a mean follow-up of 6.52 ± 1.14 years, incident CVD, MI and stroke occurred in 2057, 395 and 1695, respectively. The risk of developing CVD increased with the quartile of cumulative in TyG index, after adjustment for multiple potential confounders, the HR for CVD events were 1.25 (1.08–1.44) in Q2, 1.22 (1.05–1.40) in Q3 and 1.39 (1.21–1.61) in Q4, compared to Q1 group. The longer duration of higher TyG index exposure was significantly associated with increased CVD risk. Similar results were obtained in the subgroup and sensitivity analysis.

Conclusion

Cumulative TyG index was associated with increased risk of CVD. Maintaining an appropriate level of TG and FBG within the desirable range and better control of cumulative TyG index are important for prevention of CVD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01456-1.

Using the Power of Junctional Adhesion Molecules Combined with the Target of CAR-T to Inhibit Cancer Proliferation, Metastasis and Eradicate Tumors

Decades of evidence suggest that alterations in the adhesion properties of neoplastic cells endow them with an invasive and migratory phenotype. Tight junctions (TJs) are present in endothelial and epithelial cells. Tumors arise from such tissues, thus, the role of TJ proteins in the tumor microenvironment is highly relevant. In the TJ, junctional adhesion molecules (JAM) play a key role in assembly of the TJ and control of cell–cell adhesion. Reprogramming of immune cells using chimeric antigen receptors (CAR) to allow for target recognition and eradication of tumors is an FDA approved therapy. The best-studied CAR-T cells recognize CD19, a B-cell surface molecule. CD19 is not a unique marker for tumors, liquid or solid. To address this limitation, we developed a biologic containing three domains: (1) pH-low-insertion peptide (pHLIP), which recognizes the low pH of the cancer cells, leading to the insertion of the peptide into the plasma membrane. (2) An extracellular domain of JAM proteins that fosters cell–cell interactions. (3) CD19 to be targeted by CAR-T cells. Our modular design only targets cancer cells and when coupled with anti-CD19 CAR-T cells, it decreases proliferation and metastasis in at least two cancer cell lines.

Characterization of Extramedullary Disease in B-ALL and Response to CAR T-cell Therapy

A substantial fraction of patients with relapsed/refractory B-ALL will have non-CNS EMD.

CAR T cells may have limited efficacy in multifocal non-CNS EMD, and serial imaging is needed to identify and monitor EMD.

Chimeric antigen receptor (CAR) T cells effectively eradicate medullary B-cell acute lymphoblastic leukemia (B-ALL) and can traffic to and clear central nervous system (CNS) involvement. CAR T-cell activity in non-CNS extramedullary disease (EMD) has not been well characterized. We systematically evaluated CAR T-cell kinetics, associated toxicities, and efficacy in B-ALL non-CNS EMD. We conducted a retrospective review of B-ALL patients with non-CNS EMD who were screened for/enrolled on one of three CAR trials (CD19, CD22, and CD19/22) at our institution. Non-CNS EMD was identified according to histology or radiographic imaging at extramedullary sites excluding the cerebrospinal fluid and CNS parenchyma. Of ∼180 patients with relapsed/refractory B-ALL screened across multiple early-phase trials over an 8-year period, 38 (21.1%) presented with isolated non-CNS EMD (n = 5) or combined medullary/non-CNS EMD (n = 33) on 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging. A subset receiving CAR T cells (18 infusions) obtained FDG PET/CT scans preinfusion and postinfusion to monitor response. At best response, 72.2% (13 of 18) of patients showed a medullary minimal residual disease–negative complete remission and complete (n = 7) or partial (n = 6) non-CNS EMD response. Non-CNS EMD responses to CAR T cells were delayed (n = 3), and residual non-CNS EMD was substantial; rarely, discrepant outcomes (marrow response without EMD response) were observed (n = 2). Unique CAR-associated toxicities at non-CNS EMD sites were seen in select patients. CAR T cells are active in B-ALL non-CNS EMD. Still, non-CNS EMD response to CAR T cells may be delayed and suboptimal, particularly with multifocal disease. Serial FDG PET/CT scans are necessary for identifying and monitoring non-CNS EMD.