TP53 Deficiency in AML Confers Resistance to CAR T-Cells That Can be Overcome By Targeting the Cholesterol or Wnt Pathways

Optimizing the IFNγ Axis Improves CAR T-Cell Potency in AML but Not B-ALL

TP53-mutant acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS) are characterized by chemotherapy resistance and represent an unmet clinical need. Chimeric antigen receptor (CAR) T-cells might be a promising therapeutic option for TP53-mutant AML/MDS. However, the impact of TP53 deficiency in AML cells on the efficacy of CAR T-cells is unknown. We here show that CAR T-cells engaging TP53-deficient leukemia cells exhibit a prolonged interaction time, upregulate exhaustion markers, and are inefficient to control AML cell outgrowth in vitro and in vivo compared to TP53 wild-type cells. Transcriptional profiling revealed that the mevalonate pathway is upregulated in TP53-deficient AML cells under CAR T-cell attack, while CAR T-cells engaging TP53-deficient AML cells downregulate the Wnt pathway. In vitro rational targeting of either of these pathways rescues AML cell sensitivity to CAR T-cell-mediated killing. We thus demonstrate that TP53 deficiency confers resistance to CAR T-cell therapy and identify the mevalonate pathway as a therapeutic vulnerability of TP53-deficient AML cells engaged by CAR T-cells, and the Wnt pathway as a promising CAR T-cell therapy-enhancing approach for TP53-deficient AML/MDS.

6518 Background: Chimeric antigen receptor (CAR) T-cell therapy has shown promising efficacy in B-cell malignancies (Majzner RG, et al. Nat Med. 2019 Sep;25(9):1341-1355). However, its feasibility in acute myeloid leukemia (AML) is not fully established. CD33 CAR T-cell therapy in relapsed or refractory (r/r) AML have reported limited or no significant anti-leukemic effects (Tambaro FP, et al. Leukemia. 2021 Nov;35(11):3282-3286; Wang QS, et al. Mol Ther. 2015 Jan;23(1):184-91). CD123 CAR T-cell therapy has weak proliferation and low CR rates (Wermke M, et al. Blood. 2021 Jun 3;137(22):3145-3148; Cummins, Katherine D. et al. Blood. 2017; 130: 1359), while CLL1 CAR T-cell therapy has induced anti-leukemic responses in a small subset of patients without sustained expansion (Pei K, et al. Cancer Med. 2023 Apr;12(8):9655-9661; Jin X, et al. J Hematol Oncol. 2022 Jul 7;15(1):88). Here, we present early safety and efficacy of functionally enhanced CD33 CAR T cells in AML. Methods: We improved the performance of CD33 CAR T cells by adding a potentiating molecule linked to human CD33 scFv by P2A. The study was registered with ClinicalTrials.gov (NCT04835519). The trial used the “3+3” approach, starting with an initial dose of 5×105 (±20%)/kg. The primary endpoint was safety with efficacy secondary. Results: Four relapsed patients, including three who underwent stem cell transplantation, were enrolled and received initial dose of CAR T cells between April 13, and July 28, 2021. The Data and Safety Monitoring Committee approved the preliminary report. Three patients (75%) experienced grade 1−2 cytokine release syndrome (CRS), while one (25%) had grade 4 CRS. One developed grade 2 CRS after the second infusion. One patient had dose-limiting toxicity. Two patients (50%) had grade 1 neurotoxicity, and two (50%) developed grade 1–2 graft-versus-host disease. All patients experienced grade 2–4 neutropenia, monocytopenia, and thrombocytopenia. One patient developed sepsis. Two patients achieved CR with incomplete hematologic recovery (CRi) and were MRD-negative at day 30, while two had no response. Of these, one patient received a second infusion and achieved MRD+ CRi. Two patients have remained disease free for over two years. One patient remained disease free for one year before CD33+ relapse. The two patients with CRi had peak CAR T cell counts of 192 and 23.5 cells/μl, while the two without CRi had lower peak counts of 2.12 and 10.3 cells/μl. One patient peaked at 1.73 cells/μl after the second infusion. The two patients with CRi also had a higher proportion of CAR T cells among the lymphocytes (46.8% and 53.0%). As expected, peripheral blood CD33+ cells decreased. Conclusions: We report the safety and efficacy of functionally enhanced CD33 CAR T cells. While some patients had CRi, there was also depletion of CD33-positive normal cells. Thus, further research is needed to address the issue of normal cell depletion. Clinical trial information: NCT04835519 .

Dual Split-Signaling TIM3+CLEC12a Targeting CAR T-Cells with Optimized Signaling As a Safe Potential Therapy for Acute Myeloid Leukemia

Advancing the Integration of CAR T-Cell Therapy in Community Oncology Centers: Key Findings from a Transformative Quality Improvement Initiative

<p>Anti-CD19 Chimeric Antigen Receptor (CAR) T-cell therapy is shifting the treatment paradigm internationally for selected patients with relapsed and refractory B-cell Non- Hodgkin Lymphoma. Despite high response rates with durable responses achieved in a significant proportion of patients, over 50% of patients will have progressed at one year following treatment with the currently licensed anti-CD19 CAR T-cell therapies. This modality of therapy is also associated with acute and potentially life-threatening toxicities, requiring strict risk mitigation strategies. In this thesis, the design, preparation and implementation of a new third generation anti-CD19 CAR T-cell Phase 1 trial entitled ENABLE, for patients with relapsed and refractory B-cell Non-Hodgkin Lymphoma, is described in detail. Following a literature review of CAR T-cell therapy in patients with B-cell Non-Hodgkin Lymphoma, the rationale for the ENABLE trial design is discussed, along with regulatory and clinical requirements for setting up CAR T-cell therapy in New Zealand. The importance of international collaboration to inform aspects of study design, CAR T-cell product manufacturing and developing CAR T-cell toxicity management protocols, has been demonstrated. The early clinical experience on the ENABLE trial is presented along with provisional safety, pharmacokinetic and efficacy data from the first participant treated. This is the first time that CAR T-cell therapy has been administered in New Zealand, demonstrating CAR T-cell expansion in vivo; but also highlighting the complexities of the CAR T-cell product manufacturing process and the importance of evaluating feasibility of CAR T-cell manufacturing, as a key secondary endpoint of the study. Further clinical experience on the ENABLE trial is crucial to develop the potential for CAR T-Cell therapy to be a safe, feasible and effective option for selected New Zealand patients in the future.</p>

<p>Anti-CD19 Chimeric Antigen Receptor (CAR) T-cell therapy is shifting the treatment paradigm internationally for selected patients with relapsed and refractory B-cell Non- Hodgkin Lymphoma. Despite high response rates with durable responses achieved in a significant proportion of patients, over 50% of patients will have progressed at one year following treatment with the currently licensed anti-CD19 CAR T-cell therapies. This modality of therapy is also associated with acute and potentially life-threatening toxicities, requiring strict risk mitigation strategies. In this thesis, the design, preparation and implementation of a new third generation anti-CD19 CAR T-cell Phase 1 trial entitled ENABLE, for patients with relapsed and refractory B-cell Non-Hodgkin Lymphoma, is described in detail. Following a literature review of CAR T-cell therapy in patients with B-cell Non-Hodgkin Lymphoma, the rationale for the ENABLE trial design is discussed, along with regulatory and clinical requirements for setting up CAR T-cell therapy in New Zealand. The importance of international collaboration to inform aspects of study design, CAR T-cell product manufacturing and developing CAR T-cell toxicity management protocols, has been demonstrated. The early clinical experience on the ENABLE trial is presented along with provisional safety, pharmacokinetic and efficacy data from the first participant treated. This is the first time that CAR T-cell therapy has been administered in New Zealand, demonstrating CAR T-cell expansion in vivo; but also highlighting the complexities of the CAR T-cell product manufacturing process and the importance of evaluating feasibility of CAR T-cell manufacturing, as a key secondary endpoint of the study. Further clinical experience on the ENABLE trial is crucial to develop the potential for CAR T-Cell therapy to be a safe, feasible and effective option for selected New Zealand patients in the future.</p>

Pediatric cancer poses a major health challenge globally, especially in low-middle-income countries like Indonesia. The survival rate of pediatric cancer in many high-income countries (HICs) reaches 90%, while it only ranges from 5 to 60% in LMICs. Over 80% of children with cancer live in low-middle-income countries, indicating the urgency to improve the survival rate of pediatric cancer in LMICs [1]. In Indonesia, the prevalence of pediatric cancer was 43.5% in 2020, making it the highest among Southeast Asian countries [2]. According to Dharmais Cancer Hospital (2024), the national cancer referral center for all of Indonesia, the 5-year survival rate of high-risk pediatric acute lymphoblastic leukemia is only 48.8% (unpublished data).One key factor contributing to the low survival rate of pediatric cancer in Indonesia is the lack of effective therapy options, especially for high-risk and relapsed or refractory patients. Several therapeutic approaches, such as immunotherapy, have been widely used in HICs but are still not very popular in Indonesia. CAR (Chimeric Antigen Receptor) T-cell therapy is one of the most promising immunotherapeutic approaches to treat pediatric cancer. Implementing CAR T Cell therapy in Indonesia offers promising prospects for improving the survival rates of pediatric cancer patients.CAR T cell therapy utilizes the body's immune system to specifically target and eliminate cancer cells. This innovative therapy entails extracting a patient's T cells, genetically modifying them to express chimeric antigen receptors specific to tumor-associated antigens, and then reinfusing them into the patient. Once infused, these engineered T cells recognize and eliminate cancer cells bearing the targeted antigen, thereby offering a highly targeted and potentially curative treatment option [3]. This innovative therapy has demonstrated remarkable success in treating certain hematologic malignancies, including pediatric leukemia. The most extensively studied case in childhood patients involves CAR T cells that target CD19, a B cell surface receptor [4].CAR T cell therapy holds great promise for improving survival rates among pediatric cancer patients in Indonesia. Children with refractory or relapsed leukemia, such as B-cell acute lymphoblastic leukemia (B-ALL), who have exhausted standard treatment options, can benefit from CAR T cell therapy. Most relapsed or refractory pediatric cancer patients in Indonesia do not have effective therapy options to treat the disease. CAR T cell therapy emerges as a novel therapy that can significantly improve the survival of this subset of patients. Numerous studies have documented high remission rates (ranging from 70% to 90%) in adults and children diagnosed with refractory B-ALL [4]. A study by Maude et al. [5] reported high remission rates and durable responses in young adults and children with refractory or relapsed B-ALL treated with CAR T cells. Similarly, Park et al. [6] demonstrated long-term remissions and improved survival in pediatric leukemia patients receiving CAR T cell therapy. Several groups also have observed the persistence of CAR T cells and sustained remission lasting over six months in the majority of patients examined [4]. Efforts have been made to implement CAR T cells in Indonesia. Dharmais Cancer Hospital, as a National Cancer Center in Indonesia, has initiated this effort by collaborating with iCarTAB Biomed Inc., a China-based CAR T cell manufacturer with one of its manufacturing sites located in Malaysia. However, this approach involves sending patients' blood samples that have been processed through leukapheresis to Malaysia for CAR T cell manufacturing, followed by the shipment of the manufactured cells back to Indonesia for administration to patients. This process is impractical and incurs intangible costs such as transportation and cryopreservation, ultimately making it more expensive for patients. Regulatory issues related to the shipment of cells across borders in the region and early preparation of patients for CAR T cell therapy soon after relapse before they succumb to treatment-related mortality or relapse-related complications are also challenges that need to be addressed [7]. Reflecting on the abovementioned issue, CAR T cell therapy adoption in Indonesia faces significant challenges. Limited healthcare infrastructure, including specialized facilities for cell therapy manufacturing and administration, poses logistical hurdles. Moreover, cost remains a major barrier, as CAR T cell therapy is often expensive and inaccessible to many patients in Indonesia. Furthermore, the lack of local expertise in cellular immunotherapy may impede the successful implementation of CAR T cell therapy programs.Efforts to address these challenges and maximize the potential of CAR T cell therapy in Indonesia are essential. This requires a multi-faceted approach involving investment in healthcare infrastructure, including establishing specialized centers equipped for CAR T cell therapy manufacturing and administration. Two alternative models have been proposed for manufacturing CAR-T cell therapy: centralized and de-centralized models [8]. In the centralized manufacturing model, point of manufacturing and point of care are located in different geographical areas, while decentralized manufacturing focuses on establishing point of care and manufacturing in close proximity. A decentralized manufacturing model might be the best approach to be implemented in LMICs like Indonesia. Building hospital-based cellular therapy manufacturing reduces the need for transportation and cryopreservation. The decentralized system's geographic proximity improves communication between manufacturing and treatment teams, facilitating the creation of customized products based on a patient's phenotype. This setup also reduces administration time and the risk of delays and mix-ups compared to centralized manufacturing, making hospital-based cellular therapy manufacturing a potentially more cost-effective option [8].In addition, initiatives to reduce the cost of therapy through partnerships with pharmaceutical companies, government subsidies, or philanthropic endeavors can improve affordability and access. Furthermore, capacity-building initiatives aimed at training local healthcare professionals in cellular immunotherapy techniques are essential for ensuring the successful implementation and sustainability of CAR T cell therapy programs in Indonesia. Collaboration between local institutions, international organizations, and industry stakeholders can facilitate knowledge transfer and technology transfer, fostering indigenous expertise in this cutting-edge treatment modality.CAR T cell therapy represents a transformative approach to improving survival rates among pediatric cancer patients in Indonesia. By harnessing the power of immunotherapy, specifically tailored to target cancer cells, CAR T cell therapy offers hope for children with refractory or relapsed leukemia who have limited treatment options. Through continued research, collaboration, and investment in healthcare infrastructure, CAR T cell therapy potentially could greatly improve the prognosis and quality of life for pediatric cancer patients in Indonesia.

BackgroundCD19-directed chimeric antigen receptor (CAR) T-cell therapy has revolutionized cancer care for patients with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL). Despite impressive responses seen with CAR T-cell treatment, nearly 30–50% of patients will relapse with very poor outcomes and the mechanism of relapse if oftentimes unknown. Next-generation sequencing (NGS) is a novel technology that can detect genomic biomarkers and provide insight into treatment resistance and cancer prognosis. This report highlights a case where NGS was able to detect the presence of the CAR T-cell construct in a patient after CAR T-cell therapy relapse.Case presentationWe present a 20-year-old, White, male patient with R/R DLBCL who was treated with CD19 CAR T-cell therapy and relapsed approximately six months after infusion. Biopsy showed CD19-negative disease. Interestingly, NGS detected the presence of the CAR T-cell construct even after the patient progressed following CAR T-cell therapy, suggesting continued persistence of the CAR T-cells.ConclusionsPrognosis of patients who relapse after CAR T-cell therapy for R/R DLBCL remains poor as mechanisms and predictors of relapse are not well understood. It is necessary to consider how novel technologies can be incorporated into the prognostication and monitoring of response to CAR T-cell therapy. In our case, the ability of NGS to distinguish the CAR T-cell product suggests that NGS may have the potential to ascertain CAR T-cell response and provide insight into the purported mechanism of relapse after CAR T-cell therapy. This report highlights a potentially new approach to monitoring patients with R/R DLBCL following CAR T-cell therapy using NGS technology.

Key Findings from a Transformative Quality Improvement Initiative on Advancing CAR T-Cell Treatment in Non-Hodgkin Lymphoma

<div>Abstract<p>Chimeric antigen receptor (CAR) T-cell therapy is increasingly being adopted as a clinical modality for patients with relapsed/refractory hematologic malignancies. Despite the clinical efficacy of CAR T-cell therapy, a considerable fraction of patients still relapse during the first months following CAR T-cell infusion. The limited CAR T-cell efficiency is thought to relate to epigenetic mechanisms involved in T-cell suppression and dysfunction. In this study, screening of multiple epigenetic inhibitors revealed that targeting polycomb repressive complex 2 (PRC2) consistently induced the development of granzyme B<sup>+</sup> effector memory CD8 T cells. Notably, PRC2 inhibition also promoted the long-term persistence of granzyme B<sup>+</sup> effector memory 19BBζ CAR T cells and enhanced sustainably their antitumor activity both <i>in vitro</i> and <i>in vivo</i>. Consistent with their long-lasting antitumor activity, PRC2-inhibited 19BBζ CAR T cells did not exhibit signs of exhaustion over time. Furthermore, TCR restimulation along with PRC2 inhibition promoted the differentiation of patient-derived anti-CD19 effector memory CAR T cells with enhanced cytotoxic features and elicited potent antitumor responses. In line with this, the gene signature derived from in-house PRC2-inhibited 19BBζ CAR T cells was enriched in tisagenlecleucel BBζ CAR T-cell therapy responders with large B-cell lymphoma. Collectively, our results demonstrated that targeting PRC2 may be a promising approach to enhance a functional effector program in CAR T cells against hematologic malignancies.</p>Significance:<p>Selective inhibition of PRC2 endows 19BBζ CAR T cells with cytotoxic and effector memory features that are associated with improved antitumor activity and better response to CAR T-cell therapy.</p></div>

Efficient Human Acute Myeloid Leukemia Targeting By Universal Chimeric Antigen Receptor T-Cells Via Combinatorial Use of Linkers

Efficient Combinatorial Adaptor-Mediated Targeting of Acute Myeloid Leukemia with CAR T-Cells

Incidence of Secondary Malignancy after Treatment with Anti-CD19 and Anti-BCMA Chimeric Antigen Receptor T-Cell Therapies

CD84: A Novel Target for CAR T-Cell Therapy for Acute Myeloid Leukemia