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Glioblastoma (GBM) is the most common and aggressive type of cancerous brain tumor in adults. People with GBM generally expect to live 12 to 18 months after diagnosis. Despite decades of research, there is no known cure for GBM, and treatments have only a limited effect on extending an individual's life expectancy. However, researchers have tested a technology that delivers CAR-T cells targeting two proteins commonly found in brain tumors: epidermal growth factor receptor (EGFR), estimated to be present in 60% of all GBMs, and interleukin-13 receptor alpha 2 (IL13Rα2), which is expressed in over 75% of GBMs. While CAR-T cell therapy for blood cancers is usually administered intravenously, the researchers administered these dual-targeted CAR-T cells intrathecally, by injection into the cerebrospinal fluid, so that the modified cells could reach the tumors more directly in the brain. Magnetic Resonance Imaging scans taken 24 to 48 hours after administration of dual-targeted CAR-T cells targeting EGFR and IL13Rα2 revealed a reduction in tumor size in all six patients, and these reductions were maintained up to several months later in a subgroup of patients. 

Following the approval from the Food and Drug Administration (FDA), doctors at the University of Washington's Siteman Cancer Center will administer tumor-infiltrating lymphocyte (TIL) therapy to treat certain adult patients with metastatic melanoma, an aggressive skin cancer that has spread to other areas of the body. The treatment is intended for patients with metastatic melanoma that cannot be treated by surgery and has continued to grow and spread despite having already been heavily treated with other approved strategies, including chemotherapy and immune checkpoint inhibitors. The first centers to administer TIL therapy are those with extensive expertise in treating patients with cellular immunotherapies, such as CAR-T cell therapy for blood cancers. For the therapy, doctors at an approved treatment center take a sample of the tumor and send the tissue to an Iovance manufacturing facility, where tumor-infiltrating lymphocytes are isolated from the tumor and then expanded outside the body. This TIL therapy cell product is then cryopreserved and returned to the patient. When returned to the patient's body via intravenous infusion, the tumor-specific T cells, now numbering in the billions, are much more effective at killing tumor cells throughout the body. 

Researchers have reported promising results in a Phase I/II trial involving 37 patients with relapsed or refractory B-cell malignancies who were treated with a cord blood-derived natural killer (NK) chimeric antigen receptor (CAR), a cell therapy targeting CD19. Results showed an overall response (OR) rate of 48.6% 100 days after treatment, with one-year progression-free survival (PFS) and overall survival (OS) rates of 32% and 68%, respectively. The trial reported an excellent safety profile, with no cases of cytokine release syndrome (CRS), neurotoxicity or graft-versus-host disease. Another key finding of the trial was the importance of allogeneic cord blood donor selection criteria in the manufacture of CAR NK cells. Cord blood units cryopreserved within 24 hours of collection and those with a low content of nucleated red blood cells were associated with significantly better results. CAR NK cells generated from these units resulted in a one-year PFS rate of 69% and an OS rate of 94%, compared with 5% and 48%, respectively, for units with higher nucleated red cell content or longer collection to cryopreservation times. 

Solid tumors generate anti-immune signals that deactivate CAR T cells, making treatment less effective. To solve this problem, scientists have combined CAR T cells with cytokine injection, which can cause significant unintended toxicities. Researchers replaced the extracellular domain of various cytokine receptors with leucine zippers to create constitutively active receptors. CAR T cells expressing one of these chimeric cytokine receptors had superior antitumor activity against several types of cancer in cell lines and mouse models compared with conventional CAR T cells. Although chimeric cytokine receptors give a constant "on" signal to CAR T cells, they do not induce non-specific proliferation of CAR T cells. The system thus limits the effect of cytokine signaling to modified cells only, reduces the risk of cytokine-related toxicity, and provides a signal that these CAR T cells should function effectively in a suppressive tumor microenvironment. 

CAR T cells have become an established treatment option for children with a rare form of relapsed or incurable leukemia. One of the key factors determining whether treatment will lead to lasting remission of leukemia is how long the CAR T cells live in the body. One team was able to study the cells of 10 children enrolled in a pioneering clinical trial (CARPALL) for up to five years after their initial CAR T cell treatment. This has enabled them to better understand why some of these CAR T cells remain in a patient's bloodstream, and why others disappear early, potentially allowing the cancer to recur. Using techniques that analyze individual cells at the genetic level to understand what they do, the scientists were able to identify a unique "signature" in long-lived CAR T cells. The signature suggested that long-lived CAR T cells in the blood transformed into a different state that allowed them to continue monitoring the patient's body for cancer cells. As part of the study, the researchers identified key genes in CAR T cells that appeared to enable them to persist in the body for a long time. These genes will provide a starting point for future studies to identify markers of persistence in CAR T-cell products as they are manufactured, and ultimately to improve their efficacy.

Three young patients with relapsing T-cell leukemia have now been treated with CAR T cells. Data from the clinical trial show how the donor CAR T cells were engineered using cutting-edge gene-editing technology to modify single letters of their DNA code so that they could fight leukemia. To generate "universal" anti-T CAR T cell banks for the study, the researchers used T cells from healthy donors. They then made modifications to the cells using basic editing. The steps were: the deletion of existing receptors so that a donor's T cells could be banked and used without pairing, making them "universal", the deletion of a "flag" called CD7 so that T cells would not kill each other, the deletion of a second "flag" called CD52 to make the edited cells invisible to some of the potent drugs administered to the patient during the treatment process, and the addition of a chimeric antigen receptor that recognizes the CD7 T-cell receptor on leukemic T-cells to combat T-cell leukemia. The clinical trial for this treatment is still open and aims to recruit up to 10 patients. The teams hope that the treatment can be offered earlier in the treatment pathway. With additional funding, they also hope to make it available for adults in the future. 

Immunotherapy, particularly CAR T-Cell cancer therapy, extends the lives of many patients. But sometimes the therapy randomly migrates to places it shouldn't go, sneaking into the lungs or other non-cancerous tissue and causing toxic side effects. However, a team of researchers has discovered the molecule responsible for guiding T cells to tumors, setting the stage for scientists to improve the revolutionary treatment. Their discovery of the crucial migration control gene that expresses ST3GAL1 is the result of "unbiased genomic screening": researchers used a state-of-the-art CRISPR technique to edit thousands of genes expressed in T cells, then tested the migration control capabilities of these genes, one by one over a period of nearly four years, in mouse models. The next step is to find a drug that can manipulate the key T cell protein, ST3GAL1. If the study progresses as planned, such a drug could be added to the CAR T-cell regimen to ensure that the T cells reach their targets

CAR T cells have shown some success in the clinic in treating certain cancers, such as relapsed leukemia. However, CAR T cells have not been successful in delivering solid tumors, in part because of problems with immune cell activation. Adding a molecular anchor to the key protein used to recognize cancer in cellular immunotherapies can make treatments much more effective. The researchers found that immune cells with the anchored protein increased cancer killing, regardless of their cell type or the type of cancer targeted. The concept of molecular anchoring is thus a new design for improving chimeric antigen receptor (CAR) based immunotherapies. Anchored CARs have increased survival in animal models of several tumor types, including lung, bone and brain cancers. CARs have shown promise in the clinic, but have not yet achieved widespread success in all tumor types. The findings were published in Nature Biotechnology.

T-cell transfer therapies have not yet been successfully applied to solid tumors because T cells do not readily penetrate and persist in solid tumor masses for long periods of time, and because their activity is attenuated by an immunosuppressive tumor microenvironment. One way to overcome these limitations could be to couple T cell transfer therapies with cytokine therapy. However, a serious drawback of this approach is the significant side effects resulting from cytokines circulating freely in the body, leading to toxicity and potentially fatal inflammatory syndromes. Now, researchers have developed a nanotechnology-based solution to these problems. The method uses an unnatural sugar that is absorbed and embedded in the outer coating of T cells, which can then be used to anchor cytokines. The concentrated cytokines improve T-cell function locally without producing unwanted systemic side effects. In mice with melanoma, the approach also stimulated the host immune system against tumor cells, which inhibited tumor growth. As an adjunct to CAR-T cell therapy, it resulted in complete regression of lymphoma tumors at otherwise non-curative cell doses.

In most cases, the number of naturally occurring cancer-targeting T cells will be far too low to trigger an immune response capable of eradicating a patient's tumor(s). PACT Pharma is a privately held biopharmaceutical company developing personalized, neo-antigen-specific T-cell receptor (TCR)-T therapies to treat a range of solid tumors.  Patient T cells are isolated and CRISPR-modified by electroporation with Cas9 protein, guide RNAs to knock out endogenous TCR genes (TCRα ( TRAC) and TCRβ ( TRBC)) and an HR template plasmid encoding the transgenic neoTCR. The results of a phase 1 clinical trial that were published in Nature. The researchers report that CRISPR-modified T cells were preferentially directed to the tumor and could be recovered from post-infusion biopsies in all patients for whom biopsies were available. They also note that CRISPR-edited T cells frequently accounted for the top 2-20% of immune cells in the tumor, and a reduction in tumor size was observed in some lesions in a single lung cancer patient.

CAR T cells currently in clinical use are designed to recognize cancer cells directly and have successfully treated several blood cancers. But there have been challenges that prevent their effective use in many solid tumors. Most solid tumors are heavily infiltrated by a type of immune cell called macrophages. Macrophages help tumors grow by blocking the entry of T cells into the tumor tissue, which prevents CAR T cells and the patient's own T cells from destroying the cancer cells. To address this immune suppression at the source, the researchers engineered T cells to make a chimeric antigen receptor that recognizes a molecule on the surface of macrophages. When these CAR T cells encountered a tumor macrophage, the CAR T cell became activated and killed the tumor macrophage. Treating mice with ovarian, lung and pancreatic tumors with these macrophage-targeting CAR T cells reduced the number of tumor macrophages, shrank the tumors and prolonged their survival. The destruction of tumor macrophages allowed the mice's own T cells to access and kill the cancer cells. The researchers further demonstrated that this anti-tumor immunity was induced by the release of the cytokine interferon-gamma by CAR T cells.

Currently, too few CAR T cells become memory cells that persist and create more T cells in the long term. However, a group of researchers recently showed that the distribution of the c-Myc protein in a parental T cell may be important for this process and published this work in the journal Nature. The researchers knew that a daughter cell with more c-Myc became an effector cell. In this study, the team found that the protein complex cBAF (canonical Brg1/Brg-associated factor) interacted with c-Myc. Daughter cells with high concentrations of cBAF and c-Myc became effector T cells. The cBAF binds certain regions of chromatin, proteins on DNA. The discovery suggests that it can guide the fate of cells, what type of T cells they become, by controlling the expression of effector cell-related genes. The distribution of cBAF occurs in the first activated T cell that begins the adaptive immune response; therefore, the researchers realized that cell fate is decided early in the immune response. The researchers used the molecular information they discovered. They applied a cBAF inhibitor during CAR T cell activation to generate more memory T cells. In a preclinical model, T cells treated with an inhibitor-controlled tumor growth better than untreated cells. The treated cells also survived longer and in greater numbers.

A study published in Blood Advances reveals that magnetic resonance imaging (MRI) and lumbar puncture (LP) may not be systematically necessary in the diagnosis and management of severe cases of neurotoxicity linked to CAR T cell therapy. Instead, electroencephalogram (EEG), a non-invasive test, has proved useful in the management of these complications. The researchers examined the usefulness of these tests in 190 patients treated with CAR-T at Rennes University Hospital, where during treatment around 48% of patients developed immune effector cell-associated neurotoxicity syndrome (ICANS). The researchers assessed how the different tests affected patient treatment, such as how medications, e.g. antibiotics and anti-epileptic treatments, were prescribed based on abnormal results, and how these treatments altered patient outcomes. The results ultimately revealed that abnormal findings were more common in patients with more severe ICANS. MRI findings were often normal, and although LP and EEG often showed abnormalities, they were more common in more severe cases of ICANS. When it came to therapeutic decisions, MRI rarely led to changes, LP sometimes led to unnecessary treatments in cases of suspected infections, and EEG often resulted in adjustments to antiepileptic drugs.

CRISPR-based gene editing has become a mainstay of biological discovery, providing relatively rapid insight into the function of individual genes and targets for new therapies. However, the main challenge is that it is difficult to edit immune cells without changing their biology, hampering the ability to study immune cell behavior in all its complexity in a living organism. In an earlier study, researchers used CHimeric IMmune Editing (CHIME) to knock out a gene called Ptpn2, which has shown promise for cancer immunotherapy. The recent study published in Nature Immunology explores methods to increase the precision and versatility of CHIME, including simultaneous deletion of multiple genes and targeted application in specific cell types, also using CRISPR to disrupt genes in the edited cells once they were already back inside the animal. This research has successfully demonstrated the feasibility of various innovative approaches to genetic manipulation, offering new avenues for the study of immune gene function. 

Axi-cel CAR T therapy targets the CD19 molecule on large B-cell lymphoma cells. The ZUMA-7 trial demonstrated that axi-cel reduced the risk of disease progression, need for retreatment or death by 60% compared with standard therapy. Despite these positive results in terms of event-free survival and overall survival, some patients did not respond well to treatment or relapsed rapidly after treatment. Researchers analyzed tumor gene expression patterns from patient samples and determined that a B-cell gene expression signature and CD19 protein expression were significantly associated with improved event-free survival for patients treated with axi-cel but not with standard therapy. Patients with lower tumor cell levels of CD19 showed gene expression patterns associated with immunosuppression. These observations suggest that the tumor immune environment may play an important role in regulating axi-cel treatment and outcome. Furthermore, biomarkers associated with improved axi-cel treatment outcomes decreased as patients received more treatments, suggesting that receiving axi-cel as part of earlier treatment lines is essential to ensure better patient outcomes.

Traditional CAR-T cells, while effective against liquid cancers, face challenges in solid tumors: the cells wear out and ultimately fail to destroy the cancer completely. Ground-breaking research is providing an innovative approach to this challenge. Researchers are introducing CAR-T cells that excrete the IL-10 molecule. In other words, the cell has been designed to produce its own "drug" to stay healthy in the tumor's hostile environment. In the laboratory, this innovative CAR-T therapy systematically eradicated cancerous tumors in mouse models. What's more, in ongoing clinical trials, eleven patients have appeared to achieve complete remission with this treatment, representing a 100% success rate to date. Notably, the evidence from the laboratory study suggests the long-term efficacy of the therapy, and indicates that its manufacture could be both faster and more cost-effective than current methods 

Until now, researchers have lacked the tools to create a targeted cell therapy approach that could work on all the different forms of blood and bone marrow cancers. A new solution could solve a major problem in immunotherapy, namely the inability to target surface markers present on both cancerous and healthy cells. In the study, published today in Science Translational Medicine, researchers used CAR T cells engineered to target CD45, a surface marker present on almost all blood cells, including almost all blood cancer cells. Since CD45 is also found on healthy blood cells, the research team used CRISPR base editing to develop a method called "epitope editing" to overcome the challenges of an anti-CD45 strategy, which would otherwise result in potentially lethal low blood counts and threatening side effects. The modified version of CD45 still functions, but differs sufficiently from normal CD45 for anti-CD45 CAR T cells not to recognize and attack it. This study lays the foundations for a more universal approach that could potentially extend CAR T cell therapy to all blood cancers. 

Engineering T cells to destroy cancer cells has proved effective in treating certain types of cancer. However, it has not worked as well for solid tumors. One of the reasons for this lack of success is that T cells only target a single antigen. If some of the tumor cells don't express this antigen, they can evade T cell attack. In 2019, researchers found a way to overcome this obstacle, using a vaccine that enhances CAR-T cell efficacy. In a recent study, researchers wanted to investigate how this additional T-cell response is activated. The researchers discovered that in these vaccinated mice, metabolic changes occur in CAR-T cells that increase their production of interferon gamma, a cytokine that helps stimulate a strong immune response. This helps T cells overcome the tumor's immunosuppressive environment, which normally shuts down all T cells in the vicinity. As CAR-T cells killed tumor cells expressing the target antigen, host T cells encountered other antigens from these tumor cells, stimulating these host T cells to target these antigens and help destroy the tumor cells. Without this host T-cell response, the researchers found that tumors would regrow even if CAR-T cells destroyed most of them. 

Researchers have developed a universal receptor system that allows T cells to recognize any cell surface target, enabling highly customizable CAR T cell and other immunotherapies for treating cancer and other diseases. The new approach involves engineering T cells with receptors bearing a universal "SNAPtag" that fuses with antibodies targeting different proteins. By tweaking the type or dose of these antibodies, treatments could be tailored for optimal immune responses. The researchers showed that their SNAP approach works in two important receptors: CAR receptors, a synthetic T cell receptor that coordinates a suite of immune responses, and SynNotch, a synthetic receptor that can be programmed to activate just about any gene. In a mouse model of cancer, treatment with SNAP-CAR T cells shrunk tumors and greatly prolonged survival, an important proof-of-concept that sets the stage to test this approach in clinical trials in partnership with Coeptis Therapeutics, which has licensed the SNAP-CAR technology from Pitt. The discovery could extend into solid tumors and give more patients access to the game-changing results CAR T cell therapy has produced in certain blood cancers. With the addition of SNAP, the possibilities for customized therapies become almost endless.

One of the challenges of CAR T cell therapy in solid tumors is a phenomenon known as T cell exhaustion. Previous studies have alluded to the inflammatory regulator Regnase-1 as a potential target to indirectly overcome the effects of T-cell exhaustion, as it can cause hyperinflammation when disrupted in T cells, reviving them to produce an antitumor response. The research team hypothesized that targeting the related but independent Roquin-1 regulator at the same time could boost responses further. The team used CRISPR-Cas9 gene editing to knock out Regnase-1 and Roquin-1 individually and together in healthy donor T cells with two different immune receptors that are currently being studied in Phase I clinical trials: the mesothelin-targeting M5 CAR (mesoCAR) and the NY-ESO-1-targeting 8F TCR (NYESO TCR). Following CRISPR editing, the T cells were expanded and infused into solid tumor mouse models, where the researchers observed that the double knockout resulted in at least a 10-fold increase in modified T cells compared to knocking down Regnase-1 alone, as well as increased anti-tumor immune activity and longevity of modified T cells. In some mice, this also led to an overproduction of lymphocytes, causing toxicity.

Crystal Mackall remembers her scepticism the first time she heard a talk about a way to engineer T cells to recognize and kill cancer. Sitting in the audience at a 1996 meeting in Germany, the paediatric oncologist turned to the person next to her and said: “No way. That’s too crazy.”

Today, things are different. “I’ve been humbled,” says Mackall, who now works at Stanford University in California developing such cells to treat brain tumours.

CAR T cell therapies are generally optimized for short-term cellular responses and may not allow for long-term systemic eradication of the tumor. To enable precise control of CAR T cell function over time, a first solution has been developed. Researchers have exploited recently developed synthetic Notch receptors to design enhanced CAR T cells with a second receptor. The second receptor can recognize a tumor antigen and then cause the T cell to release the cytokine interleukin-2, but when the CAR T cells are in direct contact with the tumor cells. In a mouse model, the approach enabled CAR T infiltration of solid pancreatic and melanoma tumors, resulting in substantial tumor eradication. In addition, a second solution was developed. Researchers developed a toolbox of 11 programmable synthetic transcription factors that could be activated on demand with timed administration of FDA-approved small-molecule inducers. Using these tools, the authors designed human immune cells that activate proliferation and antitumor activity on demand. The combination of the two technological advances presented will provide an unprecedented ability to precisely control the state of therapeutic cell populations not only at the time of injection but also as the immune response unfolds in the patient.

Researchers have used CRISPR/Cas9 technology to engineer donor T cells to treat critically ill children with resistant leukemia who had otherwise exhausted all available therapies. The Phase I trial, published in Science Translational Medicine , is the first use of CRISPR-edited "universal" cells in humans and represents a significant advance in the use of genetically engineered cells for cancer treatment. In the trial, the research team constructed and applied a new generation of genome-edited "universal" T cells, which builds on previous work that used older, less precise technology. The T cells were modified using CRISPR. In addition, the piece of genetic code allows the T cells to express a CAR receptor that can recognize a marker on the surface of cancerous B cells and then destroy them. The T cells were then genetically modified with CRISPR so that they could be used "off the shelf" without the need for a donor match. In specialist clean rooms, researchers manufactured their banks of donor CAR T-cells using a single disabled virus to transfer both the CAR and a CRISPR guidance system, and then applied cutting-edge mRNA technology to activate the gene editing steps.

A small clinical trial has shown that researchers can use CRISPR gene editing to alter immune cells so that they will recognize mutated proteins specific to a person’s tumours. Those cells can then be safely set loose in the body to find and destroy their target.