Regulatory Considerations for Genome-Edited T-cell Therapies.

Methods to engineer the genomes of human cells for therapeutic intervention continue to advance at a remarkable pace. Chimeric antigen receptor-engineered T lymphocytes have pioneered the way for these therapies, initially beginning with insertions of chimeric antigen receptor transgenes into T-cell genomes using classical gene therapy vectors. The broad use of clustered regularly interspaced short palindromic repeats (CRISPR)-based technologies to edit endogenous genes has now opened the door to a new era of precision medicine. To add complexity, many engineered cellular therapies under development integrate gene therapy with genome editing to introduce novel biological functions and enhance therapeutic efficacy. Here, we review the current state of scientific, translational, and regulatory oversight of gene-edited cell products.

Dual Treatment of Refractory Focal Epilepsy and Obsessive-Compulsive Disorder With Intracranial Responsive Neurostimulation.

Purpose of the Review: Intracranial neurostimulation is a well-established treatment of neurologic conditions such as drug-resistant epilepsy (DRE) and movement disorders, and there is emerging evidence for using deep brain stimulation to treat obsessive-compulsive disorder (OCD) and depression. Nearly all published reports of intracranial neurostimulation have focused on implanting a single device to treat a single condition. The purpose of this review was to educate neurology clinicians on the background literature informing dual treatment of 2 comorbid neuropsychiatric conditions epilepsy and OCD, discuss ethical and logistical challenges to dual neuropsychiatric treatment with a single device, and demonstrate the promise and pitfalls of this approach through discussion of the first-in-human closed-looped responsive neurostimulator (RNS) implanted to treat both DRE (on-label) and OCD (off-label). Recent Findings: We report the first implantation of an intracranial closed-loop neurostimulation device (the RNS system) with the primary goal of treating DRE and a secondary exploratory goal of managing treatment-refractory OCD. The RNS system detects electrophysiologic activity and delivers electrical stimulation through 1 or 2 electrodes implanted into a patient's seizure-onset zones (SOZs). In this case report, we describe a patient with treatment-refractory epilepsy and OCD where the first lead was implanted in the right superior temporal gyrus to target the most active SOZ based on stereotactic EEG (sEEG) recordings and semiology. The second lead was implanted to target the right anterior peri-insular region (a secondary SOZ on sEEG) with the distal-most contacts in the right nucleus accumbens, a putative target for OCD neurostimulation treatment. The RNS system was programmed to detect and record the unique electrophysiologic signature of both the patient's seizures and compulsions and then deliver tailored electrical pulses to disrupt the pathologic circuitry. Summary: Dual treatment of refractory focal epilepsy and OCD with an intracranial closed-loop neurostimulation device is feasible, safe, and potentially effective. However, there are logistical challenges and ethical considerations to this novel approach to treatment, which require complex care coordination by a large multidisciplinary team.

Missense Mutations in Myc Box I Influence Nucleocytoplasmic Transport to Promote Leukemogenesis.

PURPOSE: Somatic missense mutations in the phosphodegron domain of the MYC gene (MYC Box I or MBI) are detected in the dominant clones of a subset of patients with acute myeloid leukemia (AML), but the mechanisms by which they contribute to AML are unknown. EXPERIMENTAL DESIGN: To investigate the effects of MBI MYC mutations on hematopoietic cells, we employed a multi-omic approach to systematically compare the cellular and molecular consequences of expressing oncogenic doses of wild type, threonine-58 and proline-59 mutant MYC proteins in hematopoietic cells, and we developed a knockin mouse harboring the germline MBI mutation p.T58N in the Myc gene. RESULTS: Both wild-type and MBI mutant MYC proteins promote self-renewal programs and expand highly selected subpopulations of progenitor cells in the bone marrow. Compared with their wild-type counterparts, mutant cells display decreased cell death and accelerated leukemogenesis in vivo, changes that are recapitulated in the transcriptomes of human AML-bearing MYC mutations. The mutant phenotypes feature decreased stability and translation of mRNAs encoding proapoptotic and immune-regulatory genes, increased translation of RNA binding proteins and nuclear export machinery, and distinct nucleocytoplasmic RNA profiles. MBI MYC mutant proteins also show a higher propensity to aggregate in perinuclear regions and cytoplasm. Like the overexpression model, heterozygous p.T58N knockin mice displayed similar changes in subcellular MYC localization, progenitor expansion, transcriptional signatures, and develop hematopoietic tumors. CONCLUSIONS: This study uncovers that MBI MYC mutations alter RNA nucleocytoplasmic transport mechanisms to contribute to the development of hematopoietic malignancies.

Engineered deletions of HIV replicate conditionally to reduce disease in nonhuman primates.

Antiviral therapies with reduced frequencies of administration and high barriers to resistance remain a major goal. For HIV, theories have proposed that viral-deletion variants, which conditionally replicate with a basic reproductive ratio [R0] > 1 (termed "therapeutic interfering particles" or "TIPs"), could parasitize wild-type virus to constitute single-administration, escape-resistant antiviral therapies. We report the engineering of a TIP that, in rhesus macaques, reduces viremia of a highly pathogenic model of HIV by >3log10 following a single intravenous injection. Animal lifespan was significantly extended, TIPs conditionally replicated and were continually detected for >6 months, and sequencing data showed no evidence of viral escape. A single TIP injection also suppressed virus replication in humanized mice and cells from persons living with HIV. These data provide proof of concept for a potential new class of single-administration antiviral therapies.