Genetic Engineering in the Press by GEG

CAR-T cells have shown clinical efficacy in blood cancers, but have not been as effective in solid tumors. This variation in efficacy is partly due to the fact that tumors promote T-cell depletion, in which the cells are less effective at actively killing cancer. The researchers therefore created a map for the domain of T-cell differentiation and depletion in tumors, based on high-dimensional loss-of-function genetic screening. The researchers thus mapped the transcription factors expressed in tumor-infiltrating T cells. This map will provide a guide that future researchers can refer to and use to identify ways of improving T-cell-based immunotherapies. The researchers achieved this feat using single-cell CRISPR-Cas9 screening, a gene-editing technology that analyzes the gene expression profiling of individual cells after selectively eliminating transcription factors in a comprehensive screen. By examining the gene expression pattern of an individual T lymphocyte, the researchers were able to compare them to determine which inactivated transcription factors most affected T cell differentiation and anti-cancer activity. The same approach could be more widely applicable to increase knowledge in a number of contexts.

Currently, no CAR T agents have been approved by the FDA for the treatment of solid malignancies. Several other Phase 1 clinical trials are underway to evaluate the safety and efficacy of CAR T agents, as monotherapy or in combination, in solid malignancies such as glioblastoma, as well as in other cancers. Seeking to replicate the impressive results of CAR-T cell therapies seen in patients with hematological malignancies, researchers launched the BASECAMP-1 trial (NCT04981119) in the hope of identifying patients with advanced solid tumors who would be suitable candidates for treatment in the phase 1/2 EVEREST trial (NCT05736731) evaluating the A2B530 agent. This agent was designed using the novel Tmod logical T cell therapy platform. Tmod agents contain an activating receptor, either a CAR or a T cell receptor, which recognizes an antigen on the surface of tumor cells, specifically CEA in the case of A2B530, and an inhibitory receptor, or blocker, based on the LIR-1 protein, designed to enhance the tumor specificity of the agent. The blocking part of A2B530 exploits the loss of heterozygosity of the HLA-A*02 antigen, one of the most common alleles observed in tumor cells from a US population, to prevent the CAR from affecting healthy tissues. 

Researchers have developed a cell therapy based on STAb-T cells that could be used for the treatment of T-cell acute lymphoblastic leukemia in patients for whom chemotherapy or bone marrow transplantation have not worked. The advantage of STAb therapy over CAR-T therapy is that unlike CAR T cells that express a receptor with a monospecific antibody capable of recognizing one target on the tumor, STAb therapy is based on the secretion of a special type of bispecific antibody that can recognize two targets, one on the tumor cell and one on the T cell. Thus, bispecific antibodies create a kind of artificial bridge that brings therapeutic T cells into contact with tumor cells, facilitating the elimination of the latter and keeping healthy T cells safe. This distinction is essential for treating T-cell acute lymphoblastic leukemia.

 WU-CART-007 (Wugen) is a CAR T cell therapy that targets CD7 on the surface of cancer cells. The therapy, derived from healthy donor cells, uses CRISPR/Cas9 gene editing to eliminate the CD7 receptor alpha constant and T cells to prevent CAR T cell fratricide and graft versus host disease. WU-CART-007 is being evaluated in a Phase 1/phase 2 dose escalation study in patients with relapsed or refractory T-cell ALL or T-cell lymphoblastic lymphoma. The international, multi-center trial is designed to evaluate the safety and efficacy of lymphodepletion preconditioning followed by a single dose of WU-CART-007. Recently, the FDA granted orphan drug designation to WU-CART-007 for patients with relapsed or refractory T-cell acute lymphoblastic leukemia. The designation allows manufacturers to qualify for various incentives, including tax credits for qualified clinical trials and 7 years of market exclusivity. 

ALLO-501A is a CAR T cell-based therapy for relapsed or refractory large B-cell lymphoma developed by the American company Allogene Therapeutics. The advantage of this therapy is its allogeneic approach, i.e. it is based on healthy donor cells. However, the risk of graft-versus-host disease (GVHD) must be mitigated to avoid rejection of the therapy. The CD52 gene was therefore disrupted using Cellectis TALEN technology which is common in allogeneic CAR T therapies in order to have a long-term therapeutic effect. ALLO-501A was developed from a previous ALLO-501 therapy which has rituximab, an

anti-CD20 monoclonal antibody, recognition domains, whereas these are eliminated in ALLO-501A. This approach should allow for broader use of the therapy. ALLO-501A has been in a phase 1/2 trial, which is called Alpha-2, since June 2020 and has enrolled 120 participants. The goal of this trial is to evaluate safety of escalating doses, efficacy and cell kinetics in patients. Initial clinical data are expected to be shared at the 2021 American Society of Clinical Oncology annual meeting in June.

T-cell therapy has been transformative for some blood cancers, but disappointing in solid tumors. A cell therapy being made in Philadelphia may change that.

CAR-T therapy is approved by the Food and Drug Administration for certain types of cancers and works by targeting a specific area on an immune B cell. In people with lupus, B cells can produce autoantibodies which cause inflammation and tissue damage. Some researchers think that depleting and destroying B cells may help patients with lupus.

Novartis’ CTL019 has taken a giant leap towards the finishing line in the race to get the first cancer killing CAR-T cell therapy on the market having won the support of an FDA advisory panel. - News - PharmaTimes

Swiss major Novartis is still hoping to be first to market a pioneering new class of oncology medicine known as CAR-T after getting a priority review from the FDA last night for its blood cancer med CTL019.

Novartis is gunning for its first license with CAR-T (more are in the pipeline) in kids and young adults with relapsed or refractory (R/R) pediatric and young adult patients with B-cell acute lymphoblastic leukemia (ALL).

Juno Therapeutics again came under scrutiny last month following deaths in its JCAR015 trial. Two patients died from neurotoxicity-triggered cerebral edema, the same condition that killed three others in this study in July. At the time, the FDA conducted a brief review and gave a green light for the trial to continue after only five days on clinical hold. But this time, it looks like it might be the end of the road for JCAR015.

After a promising kick off, Novartis is raising doubts about the future of its CAR-T program with its decision to dissolve and reintegrate the cell and gene therapy division into its immuno-oncology effort.

Once again, the French biotech Cellectis has hit headlines after having treated a second infant suffering from an aggressive form of Leukemia with their UCART19 therapy.

T lymphocytes possess a retinoic acid receptor alpha (RARα) that is known to control gene expression programs in the nucleus, but now also appears to function outside the cell nucleus to coordinate the initial events triggered at the cell surface that lead to T cell activation. The role of RARα has been revealed thanks to the development of CRISPR techniques, advances in imaging and mass spectrometry. The aim of this research is to identify a new pathway, or set of pathways, that could be exploited to control autoimmune diseases and inflammation, or boost immunity to eradicate tumors or fight infections. Researchers had published research showing that retinoic acid (RA) triggers nuclear RARα and the expression of genes important for the differentiation of regulatory T cells. Scientists also knew that RA, present in the blood and taken up by T cells, is then transported to the nucleus by a molecule called cellular retinoic acid-binding protein 2 (CRABP2). CRABP2 in the cytoplasm binds to RA and transports it into the cell nucleus, where it activates nuclear RARα. The researchers set out to understand which other RARα proteins interact with it. This work revealed interactions with the ZAP70 kinase. For T cells, phosphorylation prompts key proteins to act when a threat is near. 

Multiple myeloma is difficult to treat because of the heterogeneity of genomic aberrations and responses to treatment. Currently, bone marrow examinations are used for genomic evaluation at diagnosis, at evaluation of minimal residual disease and at relapse. This is an invasive procedure, but it also carries the risk of false negatives due to spatial heterogeneity. Therefore, researchers developed a non-invasive disease monitoring tool using circulating tumor DNA (ctDNA) that could aid in disease management and assess response to CAR T-cell therapy in multiple myeloma patients. The investigators developed a multiple myeloma-specific liquid biopsy panel using personalized cancer profiling by deep sequencing (CAPP-Seq) to quantify ctDNA in plasma, germline, and tumor DNA samples from multiple myeloma patients. The results suggest that ctDNA can better capture the spatial heterogeneity of the tumor. The researchers also applied CAPP-Seq to patients receiving idecabtagene vicleucel and found that those who had a response of at least 90 days had significantly lower levels of ctDNA at day 28 post-infusion than those who experienced early disease progression.

Depleted T cells exhibit poor responses to tumor antigens, and limited proliferation and persistence in vivo. With high expression of inhibitory receptors and low levels of effector proteins, they are generally associated with poor clinical outcomes. A team of researchers set out to understand the origin of this depletion using high-throughput genomic technologies, in the hope of improving the outcomes of cellular immunotherapy for patients. To identify the molecular and genetic determinants of T cell exhaustion in vitro , the researchers developed a chronic TCR evolutionary stimulation assay that summarized the state of T cell exhaustion. They then subjected depleted T cells to genome-wide CRISPR-Cas9 screens, with surprising results. After an intensive search, the team found such a target: the AT rich interaction domain 1A, otherwise known as Arid1A. This gene is involved in the regulation of transcription through chromatin remodeling in the activating and promoting regions of genes. CRISPR-Cas9 inactivation of Arid1A resulted in marked improvements in T cell performance in vitro and in vivo.

Poseida Therapeutics, a San Diego-based clinical-stage biopharmaceutical company, has received FDA approval for an investigational new drug: its first allogeneic CAR-T candidate for the treatment of relapsed or refractory multiple myeloma. The new candidate, called P-BCMA-ALLO1, is designed to target the B cell maturation antigen (BCMA), which is primarily expressed by plasma cells and certain mature B cells. P-BCMA-ALLO1 is being developed using Poseida's piggyBac®, a genetic element that "cuts and pastes" or transposes DNA between vectors and chromosomes but also the hybrid Cas-CLOVER™ site-specific gene editing system that combines the use of an enzymatically inactivated Cas9 endonuclease fused to Poseida's proprietary dimeric nuclease, Clo051. Poseida Therapeutics plans to dose the first patients with P-BCMA-ALLO1 later this year.

A new study has revealed that a new T cell genetically modified by researchers at the University of Arizona is capable of targeting and attacking the pathogenic T cells responsible for type 1 diabetes, which could lead to new immunotherapy treatments. Michael Kuhns, PhD, Associate Professor at the University Arizona College of Medicine - Department of Immunobiology in Tucson, has copied the evolutionary design of killer T cells to design with a five-module chimeric antigen receptor, 5MCAR. Dr. Kuhns worked with Thomas Serwold, PhD, of the Joslin Diabetes Center, affiliated with Harvard Medical School, to test the 5MCAR T cells in a non-obese diabetic mouse model with promising results. The results were recently published in the proceedings of the National Academy of Sciences. They therefore designed a 5MCAR that would direct killer T cells to the autoimmune T cells that are involved in type 1 diabetes. The 5MCAR T cells would completely eliminate the harmful T cells that invade the pancreas. Drs. Kuhns and Serwold recently received a bridging grant from the National Institute of Allergy and Infectious Diseases to continue their research on the use of 5MCAR T cells to prevent autoimmune diseases. 

In a discovery that might be likened to finding medicine’s version of the Loch Ness monster, a research team from Johns Hopkins Medicine, IBM Research and four collaborating institutions is the first to document the existence of long-doubted “X cell,” a “rogue hybrid” immune system cell that may play a key role in the development of type 1 diabetes. 

The researchers report the unusual lymphocyte — formally known as a dual expressor, or DE, cell — in a new paper published in the journal Cell.

A panel of cancer experts voted on what could become the first gene therapy widely available in the U.S.

Last week in the New England Journal of Medicine, clinicians at City of Hope report on a glioblastoma patient being successfully treated with his own genetically modified CAR-T cells. 
 
The patient was a 50-year-old male with recurrent multifocal glioblastoma who had already undergone standard of care therapy of resection, radiation and temozolomide. The tumors involved both the brain and the spinal cord.
 

Administration of bb2121, a novel anti–B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy, produced anti-tumor responses in heavily pretreated patients with relapsed/refractory multiple myeloma, according to interim data from an on-going phase.

Using CRISPR technology, researchers can modify T cells to attack tumors. It is ready to be tested on 18 patients with advanced stages of myeloma, sarcoma and melanoma at Penn's Perelman School of Medicine; the University of California, San Francisco; and the University of Texas MD Anderson Cancer Center in Houston.