Adoptive immunotherapy for cancer or viruses.

Adoptive immunotherapy, or the infusion of lymphocytes, is a promising approach for the treatment of cancer and certain chronic viral infections. The application of the principles of synthetic biology to enhance T cell function has resulted in substantial increases in clinical efficacy. The primary challenge to the field is to identify tumor-specific targets to avoid off-tumor, on-target toxicity. Given recent advances in efficacy in numerous pilot trials, the next steps in clinical development will require multicenter trials to establish adoptive immunotherapy as a mainstream technology.

Decade-long leukaemia remissions with persistence of CD4+ CAR T cells.

The adoptive transfer of T lymphocytes reprogrammed to target tumour cells has demonstrated potential for treatment of various cancers1-7. However, little is known about the long-term potential and clonal stability of the infused cells. Here we studied long-lasting CD19-redirected chimeric antigen receptor (CAR) T cells in two patients with chronic lymphocytic leukaemia1-4 who achieved a complete remission in 2010. CAR T cells remained detectable more than ten years after infusion, with sustained remission in both patients. Notably, a highly activated CD4+ population emerged in both patients, dominating the CAR T cell population at the later time points. This transition was reflected in the stabilization of the clonal make-up of CAR T cells with a repertoire dominated by a small number of clones. Single-cell profiling demonstrated that these long-persisting CD4+ CAR T cells exhibited cytotoxic characteristics along with ongoing functional activation and proliferation. In addition, longitudinal profiling revealed a population of gamma delta CAR T cells that prominently expanded in one patient concomitant with CD8+ CAR T cells during the initial response phase. Our identification and characterization of these unexpected CAR T cell populations provide novel insight into the CAR T cell characteristics associated with anti-cancer response and long-term remission in leukaemia.

Beyond youth: Understanding CAR T cell fitness in the context of immunological aging.

Population aging, a pervasive global demographic trend, is anticipated to challenge health and social systems worldwide. This phenomenon is due to medical advancements enabling longer lifespans, with 20% of the US population soon to be over 65 years old. Consequently, there will be a surge in age-related diseases. Senescence, characterized by the loss of biological maintenance and homeostasis at molecular and cellular levels, either correlates with or directly causes age-related phenotypic changes. Decline of the immune system is a critical factor in the senescence process, with cancer being a primary cause of death in elderly populations. Chimeric antigen receptor (CAR) T cell therapy, an innovative approach, has demonstrated success mainly in pediatric and young adult hematological malignancies but remains largely ineffective for diseases affecting older populations, such as late-in-life B cell malignancies and most solid tumor indications. This limitation arises because CAR T cell efficacy heavily relies on the fitness of the patient-derived starting T cell material. Numerous studies suggest that T cell senescence may be a key driver of CAR T cell deficiency. This review examines correlates and underlying factors associated with favorable CAR T cell outcomes and explores potential experimental and clinically actionable strategies for T cell rejuvenation.

A randomized phase 2 trial of idiotype vaccination and adoptive autologous T-cell transfer in patients with multiple myeloma.

We hypothesized that combining adoptively transferred autologous T cells with a cancer vaccine strategy would enhance therapeutic efficacy by adding antimyeloma idiotype (Id)-keyhole limpet hemocyanin (KLH) vaccine to vaccine-specific costimulated T cells. In this randomized phase 2 trial, patients received either control (KLH only) or Id-KLH vaccine, autologous transplantation, vaccine-specific costimulated T cells expanded ex vivo, and 2 booster doses of assigned vaccine. In 36 patients (KLH, n = 20; Id-KLH, n = 16), no dose-limiting toxicity was seen. At last evaluation, 6 (30%) and 8 patients (50%) had achieved complete remission in KLH-only and Id-KLH arms, respectively (P = .22), and no difference in 3-year progression-free survival was observed (59% and 56%, respectively; P = .32). In a 594 Nanostring nCounter gene panel analyzed for immune reconstitution (IR), compared with patients receiving KLH only, there was a greater change in IR genes in T cells in those receiving Id-KLH relative to baseline. Specifically, upregulation of genes associated with activation, effector function induction, and memory CD8+ T-cell generation after Id-KLH but not after KLH control vaccination was observed. Similarly, in responding patients across both arms, upregulation of genes associated with T-cell activation was seen. At baseline, all patients had greater expression of CD8+ T-cell exhaustion markers. These changes were associated with functional Id-specific immune responses in a subset of patients receiving Id-KLH. In conclusion, in this combination immunotherapy approach, we observed significantly more robust IR in CD4+ and CD8+ T cells in the Id-KLH arm, supporting further investigation of vaccine and adoptive immunotherapy strategies. This trial was registered at www.clinicaltrials.gov as #NCT01426828.

Contract development and manufacturing organization selection: critical considerations that can make or break your cell and gene therapy development.

BACKGROUND AIMS: With the increase in cell and gene therapy (CGT) clinical trials in recent years has come a subsequent increase in the number of contract development and manufacturing organizations (CDMOs). Successful transition from development and early-phase clinical trials to commercialization of a CGT product often depends on selecting the best-suited CDMO. However, many CGT companies are small biotech companies that lack expertise in the field or do not have experience selecting and transferring a process to a CDMO. METHODS: Given the interest in this topic, a roundtable with CGT developers and CDMO members at the 2023 annual meeting of the International Society of Cell and Gene Therapy Paris discussed these critical aspects of product development, including technical expertise, risk sharing and timing of partnerships. RESULTS AND CONCLUSIONS: Here, we'll analyze the considerations discussed by the panel and elaborate on other factors crucial for CGT development.

Disruption of TET2 promotes the therapeutic efficacy of CD19-targeted T cells.

Cancer immunotherapy based on genetically redirecting T cells has been used successfully to treat B cell malignancies1-3. In this strategy, the T cell genome is modified by integration of viral vectors or transposons encoding chimaeric antigen receptors (CARs) that direct tumour cell killing. However, this approach is often limited by the extent of expansion and persistence of CAR T cells4,5. Here we report mechanistic insights from studies of a patient with chronic lymphocytic leukaemia treated with CAR T cells targeting the CD19 protein. Following infusion of CAR T cells, anti-tumour activity was evident in the peripheral blood, lymph nodes and bone marrow; this activity was accompanied by complete remission. Unexpectedly, at the peak of the response, 94% of CAR T cells originated from a single clone in which lentiviral vector-mediated insertion of the CAR transgene disrupted the methylcytosine dioxygenase TET2 gene. Further analysis revealed a hypomorphic mutation in this patient's second TET2 allele. TET2-disrupted CAR T cells exhibited an epigenetic profile consistent with altered T cell differentiation and, at the peak of expansion, displayed a central memory phenotype. Experimental knockdown of TET2 recapitulated the potency-enhancing effect of TET2 dysfunction in this patient's CAR T cells. These findings suggest that the progeny of a single CAR T cell induced leukaemia remission and that TET2 modification may be useful for improving immunotherapies.

A simulation-based comparison of centralized and point-of-care supply chain strategies for autologous cell therapy.

BACKGROUND AIMS: The selection between centralized and point-of-care (POC) manufacturing supply-chain network design is a crucial consideration in the autologous cell therapy (AuCT) industry, as each approach offers its advantages and disadvantages. METHODS: This study uses a simulation-based approach to compare and examine the two strategies using the supply chain for chimeric antigen receptor T-cell therapy manufacturing as an exemplar. When does it make sense to use one manufacturing strategy over another? Currently, major manufacturers in the AuCT industry use centralized supply-chain strategies predominantly in practice. The simulation results explain the reasons for this choice. To enhance the competitiveness of the POC strategy, two operation rules are proposed and tested with the simulation. The study uses key performance indicators such as cost, fulfillment time, service level, and resource utilization to provide generic guidelines based on the findings. RESULTS: The results have revealed that (i) the centralized supply-chain strategy has a significant advantage at current demand levels of a few thousand products per year; (ii) "optimal capacity" exists for the POC strategy that minimizes the cost of goods and (iii) allowing part-time labor and order transshipment can significantly increase the competitiveness of the POC strategy. CONCLUSIONS: This study may be useful in helping commercial manufacturers make informed decisions about their manufacturing approach to enhance their competitiveness in the market and to ensure a high level of patient benefit.

International Society for Cell & Gene Therapy Position Paper: Key considerations to support evidence-based cell and gene therapies and oppose marketing of unproven products.

The field of regenerative medicine, including cellular immunotherapies, is on a remarkable growth trajectory. Dozens of cell-, tissue- and gene-based products have received marketing authorization worldwide while hundreds-to-thousands are either in preclinical development or under clinical investigation in phased clinical trials. However, the promise of regenerative therapies has also given rise to a global industry of direct-to-consumer offerings of prematurely commercialized cell and cell-based products with unknown safety and efficacy profiles. Since its inception, the International Society for Cell & Gene Therapy Committee on the Ethics of Cell and Gene Therapy has opposed the premature commercialization of unproven cell- and gene-based interventions and supported the development of evidence-based advanced therapy products. In the present Guide, targeted at International Society for Cell & Gene Therapy members, we analyze this industry, focusing in particular on distinctive features of unproven cell and cell-based products and the use of tokens of scientific legitimacy as persuasive marketing devices. We also provide an overview of reporting mechanisms for patients who believe they have been harmed by administration of unapproved and unproven products and suggest practical strategies to address the direct-to-consumer marketing of such products. Development of this Guide epitomizes our continued support for the ethical and rigorous development of cell and cell-based products with patient safety and therapeutic benefit as guiding principles.

Patient access to and ethical considerations of the application of the European Union hospital exemption rule for advanced therapy medicinal products.

Hospital exemption (HE) is a regulated pathway that allows the use of advanced therapy medicinal products (ATMPs) within the European Union (EU) under restrictive conditions overseen by national medicine agencies. In some EU countries, HE is granted for ATMPs with no demonstrated safety and efficacy; therefore, they are equivalent to investigational drugs. In other countries, HE is granted for ATMPs with demonstrated quality, safety and efficacy and for which centralized marketing authorization has not been requested. The Committee on the Ethics of Cell and Gene Therapy of the International Society for Cell & Gene Therapy reflects here on the ethical issues concerning HE application from the perspective of the patient, including risk-benefit balance, accessibility and transparency, while providing evidence that HE must not be regarded as a conduit for unproven and unethical ATMP-based interventions. Indeed, HE represents a legal instrument under which a patient's need for access to novel ATMPs is reconciled with ethics. Moreover, for some unmet medical needs, HE is the only pathway for accessing innovative ATMPs. Nonetheless, HE harmonization across EU Member States and limitations of ATMP use under the HE rule when similar products have already been granted centralized marketing authorization to avoid a parallel regulatory pathway are controversial issues whose political and economic consequences are beyond the scope of this review. Finally, the institution of an EU registry of HE applications and outcomes represents a priority to improve transparency, reduce patient risks, increase efficiency of health systems, facilitate company awareness of business opportunities and boost progressive entry of ATMPs into the therapeutic repertoire of health systems.

Autologous CD4 T Lymphocytes Modified with a Tat-Dependent, Virus-Specific Endoribonuclease Gene in HIV-Infected Individuals.

MazF is an Escherichia coli-derived endoribonuclease that selectively cleaves ACA sequences of mRNA prevalent in HIV. We administered a single infusion of autologous CD4 T lymphocytes modified to express a Tat-dependent MazF transgene to 10 HIV-infected individuals (six remaining on antiretroviral therapy [ART]; four undergoing treatment interruption post-infusion) in order to provide a population of HIV-resistant immune cells. In participants who remained on ART, increases in CD4 and CD8 T cell counts of ~200 cells/mm3 each occurred within 2 weeks of infusion and persisted for at least 6 months. Modified cells were detectable for several months in the blood and trafficked to gastrointestinal lymph tissue. HIV-1 Tat introduced ex vivo to the modified CD4+ T cells induced MazF expression in both pre- and post-infusion samples, and MazF expression was detected in vivo post-viral-rebound during ATI. One participant experienced mild cytokine release syndrome. In sum, this study of a single infusion of MazF-modified CD4 T lymphocytes demonstrated safety of these cells, distribution to lymph tissue and maintenance of Tat-inducible MazF endoribonuclease activity, as well as sustained elevation of blood CD4 and CD8 T cell counts. Future studies to assess effects on viremia and latent proviral reservoir are warranted.

Tisagenlecleucel in Children and Young Adults with B-Cell Lymphoblastic Leukemia.

BACKGROUND: In a single-center phase 1-2a study, the anti-CD19 chimeric antigen receptor (CAR) T-cell therapy tisagenlecleucel produced high rates of complete remission and was associated with serious but mainly reversible toxic effects in children and young adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). METHODS: We conducted a phase 2, single-cohort, 25-center, global study of tisagenlecleucel in pediatric and young adult patients with CD19+ relapsed or refractory B-cell ALL. The primary end point was the overall remission rate (the rate of complete remission or complete remission with incomplete hematologic recovery) within 3 months. RESULTS: For this planned analysis, 75 patients received an infusion of tisagenlecleucel and could be evaluated for efficacy. The overall remission rate within 3 months was 81%, with all patients who had a response to treatment found to be negative for minimal residual disease, as assessed by means of flow cytometry. The rates of event-free survival and overall survival were 73% (95% confidence interval [CI], 60 to 82) and 90% (95% CI, 81 to 95), respectively, at 6 months and 50% (95% CI, 35 to 64) and 76% (95% CI, 63 to 86) at 12 months. The median duration of remission was not reached. Persistence of tisagenlecleucel in the blood was observed for as long as 20 months. Grade 3 or 4 adverse events that were suspected to be related to tisagenlecleucel occurred in 73% of patients. The cytokine release syndrome occurred in 77% of patients, 48% of whom received tocilizumab. Neurologic events occurred in 40% of patients and were managed with supportive care, and no cerebral edema was reported. CONCLUSIONS: In this global study of CAR T-cell therapy, a single infusion of tisagenlecleucel provided durable remission with long-term persistence in pediatric and young adult patients with relapsed or refractory B-cell ALL, with transient high-grade toxic effects. (Funded by Novartis Pharmaceuticals; ClinicalTrials.gov number, NCT02435849 .).

Advances in automated cell washing and concentration.

The successful commercialization of cell therapies requires thorough planning and consideration of product quality, cost and scale of the manufacturing process. The implementation of automation can be central to a robust and reproducible manufacturing process at industrialized scales. There have been a number of wash-and-concentrate devices developed for cell manufacturing. These technologies have arisen from transfusion medicine, hematopoietic stem cell and biologics manufacturing where operating mechanisms are distinct from manual centrifugation. This review describes the historical origin and fundamental technologies underlying each currently available wash-and-concentrate device as well as their relative advantages and disadvantages in cell therapy applications. Understanding the specific attributes and limitations of these technologies is essential to optimizing cell therapy manufacturing.

Dual Targeting of Mesothelin and CD19 with Chimeric Antigen Receptor-Modified T Cells in Patients with Metastatic Pancreatic Cancer.

B cells infiltrate pancreatic ductal adenocarcinoma (PDAC) and in preclinical cancer models, can suppress T cell immunosurveillance in cancer. Here, we conducted a pilot study to assess the safety and feasibility of administering lentiviral-transduced chimeric antigen receptor (CAR)-modified autologous T cells redirected against mesothelin to target tumor cells along with CART cells redirected against CD19 to deplete B cells. Both CARs contained 4-1BB and CD3ζ signaling domains. Three patients with chemotherapy-refractory PDAC received 1.5 g/m2 cyclophosphamide prior to separate infusions of lentiviral-transduced T cells engineered to express chimeric anti-mesothelin immunoreceptor SS1 (CART-Meso, 3 × 107/m2) and chimeric anti-CD19 immunoreceptor (CART-19, 3 × 107/m2). Treatment was well tolerated without dose-limiting toxicities. Best response was stable disease (1 of 3 patients). CART-19 (compared to CART-Meso) cells showed the greatest expansion in the blood, although persistence was transient. B cells were successfully depleted in all subjects, became undetectable by 7-10 days post-infusion, and remained undetectable for at least 28 days. Together, concomitant delivery of CART-Meso and CART-19 cells in patients with PDAC is safe. CART-19 cells deplete normal B cells but at the dose tested in these 3 subjects did not improve CART-Meso cell persistence.

CAR T-cell product performance in haematological malignancies before and after marketing authorisation.

Chimeric antigen receptor (CAR) T cells represent a potent new approach to treat haematological malignancies. Two CAR T-cell therapies, tisagenlecleucel and axicabtagene ciloleucel, have been approved in Europe and the USA, as well as several other countries, for the treatment of leukaemia and lymphoma. These approvals marked a major milestone in the field of cell and gene therapies. However, the clinical development and regulatory evaluation of these innovative therapies faced several challenges that are considered important lessons learned for future similar products. Here, we examine the products' non-clinical and clinical data packages to outline the challenges encountered during the regulatory evaluation process in Europe, and to provide an update on their performance after authorisation.

Chimeric Antigen Receptor T Cells in Refractory B-Cell Lymphomas.

BACKGROUND: Patients with diffuse large B-cell lymphoma or follicular lymphoma that is refractory to or that relapses after immunochemotherapy and transplantation have a poor prognosis. High response rates have been reported with the use of T cells modified by chimeric antigen receptor (CAR) that target CD19 in B-cell cancers, although data regarding B-cell lymphomas are limited. METHODS: We used autologous T cells that express a CD19-directed CAR (CTL019) to treat patients with diffuse large B-cell lymphoma or follicular lymphoma that had relapsed or was refractory to previous treatments. Patients were monitored for response to treatment, toxic effects, the expansion and persistence of CTL019 cells in vivo, and immune recovery. RESULTS: A total of 28 adult patients with lymphoma received CTL019 cells, and 18 of 28 had a response (64%; 95% confidence interval [CI], 44 to 81). Complete remission occurred in 6 of 14 patients with diffuse large B-cell lymphoma (43%; 95% CI, 18 to 71) and 10 of 14 patients with follicular lymphoma (71%; 95% CI, 42 to 92). CTL019 cells proliferated in vivo and were detectable in the blood and bone marrow of patients who had a response and patients who did not have a response. Sustained remissions were achieved, and at a median follow-up of 28.6 months, 86% of patients with diffuse large B-cell lymphoma who had a response (95% CI, 33 to 98) and 89% of patients with follicular lymphoma who had a response (95% CI, 43 to 98) had maintained the response. Severe cytokine-release syndrome occurred in 5 patients (18%). Serious encephalopathy occurred in 3 patients (11%); 2 cases were self-limiting and 1 case was fatal. All patients in complete remission by 6 months remained in remission at 7.7 to 37.9 months (median, 29.3 months) after induction, with a sustained reappearance of B cells in 8 of 16 patients and with improvement in levels of IgG in 4 of 10 patients and of IgM in 6 of 10 patients at 6 months or later and in levels of IgA in 3 of 10 patients at 18 months or later. CONCLUSIONS: CTL019 cells can be effective in the treatment of relapsed or refractory diffuse large B-cell lymphoma and follicular lymphoma. High rates of durable remission were observed, with recovery of B cells and immunoglobulins in some patients. Transient encephalopathy developed in approximately one in three patients and severe cytokine-release syndrome developed in one in five patients. (Funded by Novartis and others; ClinicalTrials.gov number, NCT02030834 .).

Nonviral RNA chimeric antigen receptor-modified T cells in patients with Hodgkin lymphoma.

Chimeric antigen receptor (CAR)-modified T cells are being investigated in many settings, including classical Hodgkin lymphoma (cHL). The unique biology of cHL, characterized by scant Hodgkin and Reed-Sternberg (HRS) cells within an immunosuppressive tumor microenvironment (TME), may pose challenges for cellular therapies directly targeting antigens expressed on HRS cells. We hypothesized that eradicating CD19+ B cells within the TME and the putative circulating CD19+ HRS clonotypic cells using anti-CD19-directed CAR-modified T cells (CART19) may indirectly affect HRS cells, which do not express CD19. Here we describe our pilot trial using CART19 in patients with relapsed or refractory cHL. To limit potential toxicities, we used nonviral RNA CART19 cells, which are expected to express CAR protein for only a few days, as opposed to CART19 generated by viral vector transduction, which expand in vivo and retain CAR expression. All 5 enrolled patients underwent successful manufacturing of nonviral RNA CART19, and 4 were infused with protocol-specified cell dose. There were no severe toxicities. Responses were seen, but these were transient. To our knowledge, this is the first CART19 clinical trial to use nonviral RNA gene delivery. This trial was registered at www.clinicaltrials.gov as #NCT02277522 (adult) and #NCT02624258 (pediatric).

The long road to the first FDA-approved gene therapy: chimeric antigen receptor T cells targeting CD19.

Thirty years after initial publications of the concept of a chimeric antigen receptor (CAR), the U.S. Food and Drug Administration (FDA) approved the first anti-CD19 CAR T-cell therapy. Unlike other immunotherapies, such as immune checkpoint inhibitors and bispecific antibodies, CAR T cells are unique as they are "living drugs," that is, gene-edited killer cells that can recognize and kill cancer. During these 30 years of development, the CAR construct, T-cell manufacturing process, and clinical patient management have gone through rounds of failures and successes that drove continuous improvement. Tisagenlecleucel was the first gene therapy to receive approval from the FDA for any indication. The initial approval was for relapsed or refractory (r/r) pediatric and young-adult B-cell acute lymphoblastic leukemia in August 2017 and in May 2018 for adult r/r diffuse large B-cell lymphoma. Here we review the preclinical and clinical development of what began as CART19 at the University of Pennsylvania and later developed into tisagenlecleucel.

Emerging trends in COVID-19 treatment: learning from inflammatory conditions associated with cellular therapies.

Coronavirus disease 2019 (SARS-CoV2) is an active global health threat for which treatments are desperately being sought. Even though most people infected experience mild to moderate respiratory symptoms and recover with supportive care, certain vulnerable hosts develop severe clinical deterioration. While several drugs are currently being investigated in clinical trials, there are currently no approved treatments or vaccines for COVID-19 and hence there is an unmet need to explore additional therapeutic options. At least three inflammatory disorders or syndromes associated with immune dysfunction have been described in the context of cellular therapy. Specifically, Cytokine Release Syndrome (CRS), Immune Reconstitution Inflammatory Syndrome (IRIS), and Secondary Hemophagocytic Lymphohistiocytosis (sHLH) all have clinical and laboratory characteristics in common with COVID19 and associated therapies that could be worth testing in the context of clinical trials. Here we discuss these diseases, their management, and potential applications of these treatment in the context of COVID-19. We also discuss current cellular therapies that are being evaluated for the treatment of COVID-19 and/or its associated symptoms.

Accelerating the development of innovative cellular therapy products for the treatment of cancer.

The field of cell therapy is rapidly emerging as a priority area for oncology research and drug development. Currently, two chimeric antigen receptor T-cell therapies are approved by the US Food and Drug Administration and other agencies worldwide for two types of hematologic cancers. To facilitate the development of these therapies for patients with life-threatening cancers with limited or no therapeutic options, science- and risk-based approaches will be critical to mitigating and balancing any potential risk associated with either early clinical research or more flexible manufacturing paradigms. Friends of Cancer Research and the Parker Institute for Cancer Immunotherapy convened an expert group of stakeholders to develop specific strategies and proposals for regulatory opportunities to accelerate the development of cell therapies as promising new therapeutics. This meeting took place in Washington, DC on May 17, 2019. As academia and industry expand research efforts and cellular product development pipelines, this report summarizes opportunities to accelerate entry into the clinic for exploratory studies and optimization of cell products through manufacturing improvements for these promising new therapies.