Gene Editing Innovations in Hematology

"In a study published in Science, Triebwasser and co-first authors Laura Breda, PhD, and Tyler E. Papp demonstrated genome editing of HSCs in vivo (and ex vivo) through mRNA delivered by lipid nanoparticles (LNPs) decorated with targeting moieties. With the support of co-senior authors Stefano Rivella, PhD, from the Children’s Hospital of Philadelphia, and Hamideh Parhiz, PhD, from the Perelman School of Medicine at the University of Pennsylvania, they used LNPs targeting a stem cell factor on HSCs (CD117) for delivery of mRNA to correct human sickle cells ex vivo and to target HSCs in mice in vivo. For in vivo genome editing, the researchers delivered CD117-targeted LNPs with pro-apoptotic PUMA (p53 upregulated modulator of apoptosis) mRNA that affected HSC function in the bone marrow niche in vivo, which permitted nongenotoxic conditioning for HSCT. With cargoes like PUMA that can kill off targeted cells, Papp said that he sees this technology as eventually replacing the chemotherapy necessary to ablate malignant hemopathies that require HSCT. “Conventionally, CAR T-cell therapy is done through retroviral-based approaches that have a more permanent T-cell population, with patients showing continued success 10 years after they’ve been administered the T-cell,” said Papp. “One of the applications of this technology is for preconditioning for HSCTs or cancer chemotherapy. Instead of going through all of that, you just have to get one injection of these LNP-mRNA therapeutics, which, keep in mind, are acute—the mRNA expresses, degrades, and is gone from the body.” “The beauty of this mRNA-LNP approach is that it’s a highly modular platform where we are able to decorate the surface of these LNPs, which were the foundation for the most efficacious COVID-19 vaccines for Moderna and Pfizer, to target certain cell types, and we can modify the mRNA cargo to express (or not express) in certain cell types in the body,” said Papp, a research scientist in the lab of Drew Weissman, MD, PhD. “I think we’re on the verge of designing personalized therapeutics that can have a higher regulation of unintended side effects.”" Excerpts from Genetic Engineering & Biotechnology News article highlighting a targeted mRNA lipid nanoparticle (LNP) technology for in-vivo genome editing and protein replacement therapy, developed by Hamideh Parhiz, Stefano Rivella, and Tyler Ellis Papp- congrats! Link to Science publication below: In vivo hematopoietic stem cell modification by mRNA delivery https://lnkd.in/eRy8buWA https://lnkd.in/e8sFWgeU

"In-vivo" RNA-based gene editing model for blood disorders In a step forward in the development of genetic medicines, researchers have developed a proof-of-concept model for delivering gene editing tools to treat blood disorders, allowing for the modification of diseased blood cells directly within the body. Hematopoietic stem cells (HSCs) reside in the bone marrow, where they divide throughout life to produce all cells within the blood and immune system. In patients with non-malignant hematopoietic disorders like sickle cell disease and immunodeficiency disorders, these blood cells don’t function correctly because they carry a genetic mutation. For these patients, there are currently two avenues for potentially curative treatments, both of which involve a bone marrow transplant: a stem cell transplant with HSCs from a healthy donor, or gene therapy in which the patient’s own HSCs are modified outside of the body and transplanted back in (often referred to as ex vivo gene therapy). The former approach comes with the risk of graft versus host disease, given that the HSCs come from a donor, and both processes involve a conditioning regimen of chemotherapy or radiation to eliminate the patient’s diseased HSCs and prepare them to receive the new cells. These conditioning procedures come with significant toxic side effects, underscoring the need to investigate less-toxic approaches. One option that would eliminate the need for the above methods would be in vivo gene editing, in which gene editing tools are infused directly into the patient, allowing HSCs to be edited and corrected without the need for conditioning regimens. To validate this approach, a research team used liquid nanoparticle (LNP) to deliver mRNA gene editing tools. LNP are highly effective at packaging and delivering mRNA to cells and became widely utilized in 2020, due to the LNP-mRNA platform for two leading COVID-19 vaccines. First, the researchers tested CD117/LNP encapsulating reporter mRNA to show successful in vivo mRNA expression and gene editing. Next, the researchers investigated whether this approach could be used as a therapy for hematologic disease. They tested CD117/LNP encapsulating mRNA encoding a cas9 gene editor targeting the mutation that causes sickle cell disease. This type of gene editing converts the disease-causing hemoglobin mutation into a non-disease-causing variant. Testing their construct on cells from donors with sickle cell disease, the researchers showed that CD117/LNP facilitated efficient base editing in vitro, leading to a corresponding increase in functional hemoglobin of up to 91.7%. They also demonstrated a nearly complete absence of sickled cells, the crescent-shaped blood cells that cause the symptoms of the disease. #ScienceMission #sciencenewshighlights https://lnkd.in/gDr8c2cY

Most cell therapies hinge on gene editing. But how exactly are scientists revising the blueprint of life to unleash the potential of cells to fight diseases? Welcome to Week 10 of my Cell and Gene Therapy series, where we'll explore both 𝘃𝗶𝗿𝗮𝗹 and 𝗻𝗼𝗻-𝘃𝗶𝗿𝗮𝗹 𝗴𝗲𝗻𝗲 𝗲𝗱𝗶𝘁𝗶𝗻𝗴 approaches to cell therapy. Nature has endowed some 𝘃𝗶𝗿𝘂𝘀𝗲𝘀 with the unique ability of sneaking into our cells so they can 𝘀𝗹𝗶𝗽 𝘁𝗵𝗲𝗶𝗿 𝗴𝗲𝗻𝗲𝘁𝗶𝗰 𝗺𝗮𝘁𝗲𝗿𝗶𝗮𝗹 𝗶𝗻𝘁𝗼 𝗼𝘂𝗿 𝗗𝗡𝗔 with remarkable efficiency. But scientists have repurposed these viruses to act as 𝗰𝗮𝗿𝗿𝗶𝗲𝗿𝘀 (𝘃𝗲𝗰𝘁𝗼𝗿𝘀) to deliver therapeutic genes that can be inserted into our DNA. All six FDA-approved autologous CAR-T therapies use 𝘃𝗶𝗿𝗮𝗹 𝘃𝗲𝗰𝘁𝗼𝗿𝘀 to furnish T cells with anti-cancer modules (e.g., CAR): - Novartis's Kymriah (2017): lentiviral vector - Kite Pharma's Yescarta (2017) and Tecartus (2020): retroviral vector - Bristol Myers Squibb's Breyanzi (2021) & Abecma (2021): lentiviral vector - Janssen Inc.'s Carvykti (2022): lentiviral vector In addition, bluebird bio’s Lyfgenia (2023) uses a replication-incompetent, self-inactivating lentiviral vector to add functional copies of the hemoglobin gene into stem cells. While widely utilized due to its 𝗲𝗳𝗳𝗶𝗰𝗶𝗲𝗻𝗰𝘆 and 𝗽𝗿𝗼𝘃𝗲𝗻 𝘀𝘂𝗰𝗰𝗲𝘀𝘀, viral vectors come with notable limitations. Chief among these are: 1) the risk of 𝗿𝗮𝗻𝗱𝗼𝗺 𝗶𝗻𝘀𝗲𝗿𝘁𝗶𝗼𝗻, which could disrupt crucial genes in host cells, potentially leading to adverse effects, such as cancers; and 2) the 𝗰𝗼𝗺𝗽𝗹𝗲𝘅𝗶𝘁𝘆 𝗮𝗻𝗱 𝗵𝗶𝗴𝗵 𝗰𝗼𝘀𝘁𝘀 associated with producing viral vectors meeting necessary standards of quality and consistency. Non-viral gene editing approaches, on the other hand, transport genetic material into cells 𝘄𝗶𝘁𝗵𝗼𝘂𝘁 𝘁𝗵𝗲 𝗮𝗶𝗱 𝗼𝗳 𝘃𝗶𝗿𝘂𝘀𝗲𝘀. 𝗘𝗹𝗲𝗰𝘁𝗿𝗼𝗽𝗼𝗿𝗮𝘁𝗶𝗼𝗻 is the most popular way to deliver genetic material without viruses. It works by sending a current through cells, 𝘁𝗲𝗺𝗽𝗼𝗿𝗮𝗿𝗶𝗹𝘆 𝗼𝗽𝗲𝗻𝗶𝗻𝗴 𝗽𝗼𝗿𝗲𝘀 in the cell membrane. Many major gene editing platforms are compatible with electroporation, including CRISPR/cas9, zinc-finger, TALENs, and transposon systems. Notably, Vertex Pharmaceuticals’s CASGEVY (2023) treats sickle cell disease with genetically modified stem cells. A 𝗽𝗿𝗲𝗰𝗶𝘀𝗲 𝗺𝗼𝗱𝗶𝗳𝗶𝗰𝗮𝘁𝗶𝗼𝗻 at the enhancer region of 𝘉𝘊𝘓11𝘈 gene is achieved via CRISPR/Cas9 technology with electroporation. As electroporation becomes more widely used, a few key considerations remain: 1) the ability to 𝗳𝗶𝗻𝗲-𝘁𝘂𝗻𝗲 and optimize the electric current parameters for specific cell types and genome editing tools; 2) 𝗹𝗶𝗰𝗲𝗻𝘀𝗶𝗻𝗴 𝗳𝗲𝗲𝘀 and 𝗿𝗼𝘆𝗮𝗹𝘁𝘆 structures; and 3) the ability to maintain a fully 𝗰𝗹𝗼𝘀𝗲𝗱 𝘀𝘆𝘀𝘁𝗲𝗺 to ensure sterility and prevent contamination. What are your thoughts on the evolution of gene editing technologies in cell therapy? Share your insights or questions below!

Some hereditary genetic defects cause an exaggerated immune response that can be fatal. Using the CRISPR-Cas9 gene-editing tool, such defects can be corrected, thus normalizing the immune response, as researchers led by Klaus Rajewsky from the Max Delbrück Center now report in Science Immunology. Familial hemophagocytic lymphohistiocytosis (FHL) is a rare disease of the immune system that usually occurs in infants and young children under the age of 18 months. The condition is severe and has a high mortality rate. It is caused by various gene mutations that prevent cytotoxic T cells from functioning normally. These are a group of immune cells that kill virus-infected cells or otherwise altered cells. If a child with FHL contracts a virus—such as the Epstein-Barr virus (EBV), but also other viruses—the cytotoxic T cells cannot eliminate the infected cells. Instead, the immune response gets out of control. This leads to a cytokine storm and an excessive inflammatory reaction that affects the entire organism. “Doctors treat FHL with a combination of chemotherapy, immunosuppression and bone marrow transplantation, but many children still die of the disease," says Professor Klaus Rajewsky, who heads the Immune Regulation and Cancer Lab at the Max Delbrück Center. He and his team have therefore developed a new therapeutic strategy. Using the CRISPR-Cas9 gene-editing tool, the researchers succeeded in repairing defective T cells from mice and from two critically ill infants. The repaired cytotoxic T cells then functioned normally, with the mice recovering from hemophagocytic lymphohistiocytosis. https://lnkd.in/gTeg9Qdf

My Dec segment on groundbreaking sickle cell disease treatment: https://lnkd.in/etvwa64F A brief summary for your convenience: Sickle Cell Disease: A Painful Genetic Disorder — Sickle cell disease, affecting an estimated 100,000 people in the U.S., is characterized by blood cells forming a sickle shape, leading to severe pain and other complications. — This condition has been historically neglected by the pharmaceutical industry, particularly impacting the African American community. Breakthrough in Gene-Editing: Exa-Cel — The FDA has approved Exa-Cel, a revolutionary treatment developed by Vertex Pharmaceuticals and CRISPR Therapeutics. — This CRISPR-based therapy has shown to free 93.5% of patients from severe pain crises for at least 12 months. How Exa-Cel Works — It's the first gene-editing therapy approved in the U.S., using CRISPR-Cas9 technology. — The treatment involves editing a patient's own cells outside the body and reinfusing them, effectively making the patient their own donor. Accessibility and Cost — Approved for patients aged 12 and older, with treatments starting in nine specialized centers across the U.S. — Priced at $2.2 million per person, justified by its potential to offer a lifelong cure. Understanding the Side Effects — Common side effects include low levels of platelet cells and white blood cells, increasing the risk of bleeding and infection. — Despite these, the benefits significantly outweigh the drawbacks, marking a major milestone in treating this debilitating disease. As we witness this historic advancement in treating sickle cell disease, it's essential to recognize the impact of such innovations. This treatment not only offers hope to thousands but also highlights the importance of continued investment in gene-editing technologies. Stay tuned for more updates on life-changing medical breakthroughs by subscribing to my feed: Allan Gobbs. #SickleCellTreatment #GeneEditing #HealthcareInnovation #CRISPR