FDA sets new expectations for genome editing safety
The FDA has released draft guidance outlining how developers should assess the safety of genome-edited gene therapies using next-generation sequencing (NGS). The document provides detailed recommendations on study design, sequencing strategies, and analytical approaches for identifying off-target edits, large genomic rearrangements, unintended insertions or deletions, and chromosomal translocations. It also addresses key considerations such as assay sensitivity, sample selection, and bioinformatics workflows for interpreting sequencing data, alongside expectations for using complementary or orthogonal methods to support findings.
The guidance places particular emphasis on detecting low-frequency editing events and assessing genome integrity, including structural variants that may arise from double-strand break–based systems. It also highlights the role of patient-specific factors, including genetic background, in evaluating risk, and sets clearer expectations for how sequencing data should be generated, validated, and reported in regulatory submissions. Source
Off-the-shelf CAR-T clears residual disease in lymphoma trial
Allogene Therapeutics has reported interim results from its pivotal Phase 2 ALPHA3 study showing that its allogeneic CAR-T therapy, cemacabtagene ansegedleucel (cema-cel), achieved higher rates of minimal residual disease (MRD) clearance in patients with large B-cell lymphoma when used as a first-line consolidation therapy. At the interim futility analysis, 58.3 percent of patients receiving cema-cel were MRD-negative compared with 16.7 percent in the observation arm, alongside a marked reduction in circulating tumor DNA by day 45.
The study uses MRD status to identify patients at high risk of relapse following standard treatment and evaluate whether early intervention can eliminate residual disease. Safety findings reported no cases of cytokine release syndrome, ICANS, graft-versus-host disease, or treatment-related serious adverse events, with most patients managed in the outpatient setting. The trial also includes treatment delivery in community cancer centers, reflecting a broader effort to assess the feasibility of administering CAR-T outside specialized academic sites.Source
Cema-cel data highlight progress for allogeneic CAR-T
Cellectis has highlighted interim data from Allogene’s pivotal ALPHA3 trial of cemacabtagene ansegedleucel (cema-cel) in first-line consolidation treatment for large B-cell lymphoma. The futility analysis was triggered after the 24th patient completed Day 45 minimal residual disease (MRD) assessment and showed MRD negativity in 58.3 percent of patients in the cema-cel arm, compared with 16.7 percent in the observation arm.
According to the company, treatment was generally well tolerated at the cutoff, with most patients managed in the outpatient setting and no reported cases of cytokine release syndrome, ICANS, graft-versus-host disease, or treatment-related serious adverse events. Cellectis noted that cema-cel is derived from its UCART19 allogeneic CAR-T program and that study accrual is expected to be complete by the end of 2027. Source
CAR-T long-term follow-up period comes under review
A multi-stakeholder analysis has questioned whether the standard 15-year long-term follow-up period for CAR-T therapy remains scientifically justified. The group reviewed aggregated primary safety data from five FDA-approved CAR-T products and found that adverse events were reported only infrequently beyond three years after infusion, while secondary T-cell malignancies – the main concern tied to long-term monitoring – were reported predominantly within the first two years.
The authors propose that a five-year follow-up period may be sufficient in both clinical trial and commercial settings, and also outline a more automated data-collection model using focused electronic health record transfers into a third-party database. The paper brings together contributors from academia, patient advocacy, industry, and government, including Carl June and representatives from Novartis, Kite, Bristol Myers Squibb, and Johnson & Johnson. Source
Tumor-selective CRISPR targets cancer DNA based on methylation
Researchers from Wageningen University & Research and the Van Andel Institute have developed a CRISPR variant, ThermoCas9, that can distinguish between methylated tumor DNA and non-methylated healthy DNA. The system uses epigenetic differences – specifically DNA methylation patterns – to guide cleavage activity.
In cultured human cells, the enzyme selectively cut cancer-associated DNA sequences while largely sparing normal DNA. The study describes the biochemical basis of this selectivity and evaluates editing outcomes across different methylation states, providing a method for targeting disease-specific epigenetic signatures rather than relying solely on DNA sequence recognition. Source
Smaller CRISPR systems designed for AAV delivery constraints
Researchers at the University of Texas at Austin, in collaboration with Metagenomi Therapeutics, have reported a compact CRISPR enzyme system optimized for delivery using adeno-associated virus (AAV). The reduced size of the editing machinery allows it to fit within AAV’s limited packaging capacity, which typically restricts payloads to around 4.7 kilobases.
The study outlines the structure and function of the enzyme, along with its genome editing performance in experimental systems. The work includes characterization of editing efficiency, target specificity, and compatibility with delivery vectors, addressing a key technical constraint in the development of in vivo gene editing therapies. Source
CRISPR screens map pathways that enhance T-cell killing
A study has used CRISPR activation screening combined with Perturb-seq to identify genes and RNA pathways that influence how cancer cells respond to T-cell-mediated cytotoxicity. The approach involved systematically activating gene expression across the genome and measuring resulting phenotypes at single-cell resolution.
The researchers identified multiple regulatory pathways that increase susceptibility to T-cell killing, including mechanisms linked to antigen presentation and immune signaling. The dataset provides a functional map of gene activity associated with immune response modulation in tumor cells. Source
iPSC-derived NK cells engineered for lung cancer targeting
Researchers have developed natural killer (NK) cells derived from induced pluripotent stem cells (iPSCs) and engineered them for anti-tumor activity in lung cancer models. The study describes protocols for differentiating iPSCs into NK cells, followed by genetic modification to enhance tumor recognition and cytotoxic function.
Functional assays demonstrated the ability of the engineered NK cells to target and kill cancer cells in preclinical systems. The work also includes characterization of cell phenotype, expansion capacity, and consistency across batches, reflecting the use of iPSC platforms for standardized cell production. Source
Mixed-affinity CAR-T design reduces toxicity markers while preserving activity
Researchers have described an alternative way of tuning CAR-T performance by combining high- and low-affinity CAR populations directed at the same target epitope. The team found that while CAR affinity had only limited effects on in vitro function, it correlated h4ly with tumor control in vivo, with low-affinity binders producing milder cytokine release syndrome in humanized mouse models but also lower anti-tumor efficacy. When combined with low-affinity CARs, high-affinity CAR-T cells retained h4 function while showing reduced signs of exhaustion and lower monocyte-induced cytokine production than high-affinity CAR-T cells alone. Over longer-term in vitro and in vivo experiments, low-affinity CAR-T cells became dominant over time, suggesting greater resilience under chronic antigen exposure. Source
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