Researchers have been working for decades to bring gene therapy to the clinic, yet very few patients have received any effective gene-therapy treatments. But that doesn't mean gene therapy is an impossible dream. Even though gene therapy has been slow to reach patients, its future is very encouraging. Decades of research have taught us a lot about designing safe and effective vectors, targeting different types of cells, and managing and minimizing immune responses in patients. We've also learned a lot about the disease genes themselves. Today, many clinical trials are underway, where researchers are carefully testing treatments to ensure that any gene therapy brought into the clinic is both safe and effective.
Below are some gene therapy success stories. Successes represent a variety of approachesdifferent vectors, different target cell populations, and both in vivo and ex vivo approachesto treating a variety of disorders.
Sebastian Misztal was a patient in a hemophilia gene therapy trial in 2011. Following the treatment, Misztal no longer had spontaneous bleeding episodes. Credit: UCLH/UCL NIHR Biomedical Research Centre
Several inherited immune deficiencies have been treated successfully with gene therapy. Most commonly, blood stem cells are removed from patients, and retroviruses are used to deliver working copies of the defective genes. After the genes have been delivered, the stem cells are returned to the patient. Because the cells are treated outside the patient's body, the virus will infect and transfer the gene to only the desired target cells.
Severe Combined Immune Deficiency (SCID) was one of the first genetic disorders to be treated successfully with gene therapy, proving that the approach could work. However, the first clinical trials ended when the viral vector triggered leukemia (a type of blood cancer) in some patients. Since then, researchers have begun trials with new, safer viral vectors that are much less likely to cause cancer.
Adenosine deaminase (ADA) deficiency is another inherited immune disorder that has been successfully treated with gene therapy. In multiple small trials, patients' blood stem cells were removed, treated with a retroviral vector to deliver a functional copy of the ADA gene, and then returned to the patients. For the majority of patients in these trials, immune function improved to the point that they no longer needed injections of ADA enzyme. Importantly, none of them developed leukemia.
Gene therapies are being developed to treat several different types of inherited blindnessespecially degenerative forms, where patients gradually lose the light-sensing cells in their eyes. Encouraging results from animal models (especially mouse, rat, and dog) show that gene therapy has the potential to slow or even reverse vision loss.
The eye turns out to be a convenient compartment for gene therapy. The retina, on the inside of the eye, is both easy to access and partially protected from the immune system. And viruses can't move from the eye to other places in the body. Most gene-therapy vectors used in the eye are based on AAV (adeno-associated virus).
In one small trial of patients with a form of degenerative blindness called LCA (Leber congenital amaurosis), gene therapy greatly improved vision for at least a few years. However, the treatment did not stop the retina from continuing to degenerate. In another trial, 6 out of 9 patients with the degenerative disease choroideremia had improved vision after a virus was used to deliver a functional REP1 gene.
Credit: Jean Bennett, MD, PhD, Perelman School of Medicine, University of Pennsylvania; Manzar Ashtari, Ph.D., of The Children's Hospital of Philadelphia, Science Translational Medicine.
People with hemophilia are missing proteins that help their blood form clots. Those with the most-severe forms of the disease can lose large amounts of blood through internal bleeding or even a minor cut.
In a small trial, researchers successfully used an adeno-associated viral vector to deliver a gene for Factor IX, the missing clotting protein, to liver cells. After treatment, most of the patients made at least some Factor IX, and they had fewer bleeding incidents.
Patients with beta-Thalassemia have a defect in the beta-globin gene, which codes for an oxygen-carrying protein in red blood cells. Because of the defective gene, patients don't have enough red blood cells to carry oxygen to all the body's tissues. Many who have this disorder depend on blood transfusions for survival.
In 2007, a patient received gene therapy for severe beta-Thalassemia. Blood stem cells were taken from his bone marrow and treated with a retrovirus to transfer a working copy of the beta-globin gene. The modified stem cells were returned to his body, where they gave rise to healthy red blood cells. Seven years after the procedure, he was still doing well without blood transfusions.
A similar approach could be used to treat patients with sickle cell disease.
In 2012, Glybera became the first viral gene-therapy treatment to be approved in Europe. The treatment uses an adeno-associated virus to deliver a working copy of the LPL (lipoprotein lipase) gene to muscle cells. The LPL gene codes for a protein that helps break down fats in the blood, preventing fat concentrations from rising to toxic levels.
Several promising gene-therapy treatments are under development for cancer. One, a modified version of the herpes simplex 1 virus (which normally causes cold sores) has been shown to be effective against melanoma (a skin cancer) that has spread throughout the body. The treatment, called T-VEC, uses a virus that has been modified so that it will (1) not cause cold sores; (2) kill only cancer cells, not healthy ones; and (3) make signals that attract the patient's own immune cells, helping them learn to recognize and fight cancer cells throughout the body. The virus is injected directly into the patient's tumors. It replicates (makes more of itself) inside the cancer cells until they burst, releasing more viruses that can infect additional cancer cells.
A completely different approach was used in a trial to treat 59 patients with leukemia, a type of blood cancer. The patients' own immune cells were removed and treated with a virus that genetically altered them to recognize a protein that sits on the surface of the cancer cells. After the immune cells were returned to the patients, 26 experienced complete remission.
Patients with Parkinson's disease gradually lose cells in the brain that produce the signaling molecule dopamine. As the disease advances, patients lose the ability to control their movements.
A small group of patients with advanced Parkinson's disease were treated with a retroviral vector to introduce three genes into cells in a small area of the brain. These genes gave cells that don't normally make dopamine the ability to do so. After treatment, all of the patients in the trial had improved muscle control.
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Gene Therapy Successes - Learn Genetics
- Krystal Biotech Inc (KRYS) Reports Strong Q4 and Full Year 2023 Financial Results - Yahoo Finance - February 27th, 2024
- New sickle cell gene therapies are a breakthrough, but solving how to pay their high prices is a struggle - CNBC - February 27th, 2024
- 10 gene therapy companies you should know about - Labiotech.eu - February 27th, 2024
- Former Penn employee sues Gene Therapy Program director, alleging 'unethical and illegal conduct' - The Daily Pennsylvanian - February 27th, 2024
- Gene therapy can't cure deafness because it doesn't need to be cured - The Philadelphia Inquirer - February 27th, 2024
- Fetal surgery expert Tippi MacKenzie shifts to in-utero gene therapy - STAT - February 27th, 2024
- Therapeutic Solutions International Files Patent on Facilitating Effects of JadiCells on Gene Therapy Mediated Cell ... - Business Wire - February 27th, 2024
- CU Anschutz Set to Launch Gene Therapy Trials for Heart Disorder - University of Colorado Anschutz Medical Campus - February 27th, 2024
- ICH targets cell and gene therapies, real-world data as topics ripe for harmonization - Regulatory Focus - February 27th, 2024
- Encoded Therapeutics Announces UK CTA Approval for Dravet Syndrome Gene Therapy Candidate ETX101 - Business Wire - February 27th, 2024
- Voyager Therapeutics Announces Selection of Gene Therapy Development Candidate for Friedreich's Ataxia in ... - GlobeNewswire - February 27th, 2024
- Therapeutic Solutions International Files Patent on Facilitating Effects of JadiCells on Gene Therapy Mediated Cell ... - The Bakersfield Californian - February 27th, 2024
- Ring Therapeutics, a Flagship gene therapy startup, lays off 20% of staff - STAT - February 27th, 2024
- Ed Silverman on new gene therapies, biosimilars, coffee, and more - STAT - STAT - February 27th, 2024
- Combatting HIV using gene therapy - Drug Target Review - February 27th, 2024
- NCDHHS working with federal government on increasing access to sickle cell disease treatment - WECT - February 27th, 2024
- Cell Therapy Weekly: FDA Approves First Cell Therapy For Solid Tumors - RegMedNet - February 27th, 2024
- Rejuvenate Bio Announces Gene Therapy-Mediated Partial Reprogramming Extends Lifespan and Reverses Age ... - Business Wire - February 27th, 2024
- New sickle cell therapy uses gene editing at MUSC | Health | postandcourier.com - The Post and Courier - February 27th, 2024
- Long-term and real-world safety and efficacy of retroviral gene therapy for adenosine deaminase deficiency - Nature.com - February 18th, 2024
- Gene therapy, blood transfusions, stool monitoring: The Sydneysiders trying to escape death - Sydney Morning Herald - February 18th, 2024
- Not too late to repair: gene therapy improves advanced heart failure in animal model - Baylor College of Medicine | BCM - February 18th, 2024
- Direct Administration of CRISPR-Cas9: Tools for Cell and Gene Therapy - Forbes - February 18th, 2024
- Gene therapy's promise seen in its success for AADC deficiency - AADC News - February 18th, 2024
- First Patient Randomized in AskBio Phase II Gene Therapy Trial for Congestive Heart Failure Treatment - Diagnostic and Interventional Cardiology - February 18th, 2024
- FDA to review expanded use of Sarepta Duchenne gene therapy - Yahoo Finance - February 18th, 2024
- How gene therapy can help treat a rare blood disorder - KUTV 2News - February 18th, 2024
- CRISPR gene therapy Casgevy secures approval in Europe - Pharmaceutical Technology - February 18th, 2024
- FDA Updates for the Week of Feb. 12, 2024: New Approvals, an Extended Review and Goal Dates Set - Managed Healthcare Executive - February 18th, 2024
- First Patient Randomized in AskBio Phase II Gene Therapy Trial for Congestive Heart Failure - Business Wire - February 18th, 2024
- Lisa Jarvis: A cure for some kinds of hearing loss? Gene therapies are getting closer - St. Paul Pioneer Press - February 18th, 2024
- Spinal Muscular Atrophy Market: Navigating Therapeutic Advances towards USD 5.6 Billion by 2034, with a CAGR of ... - Yahoo Finance - February 18th, 2024
- Crispr Therapeutics' Gene Therapy Wins EU Approval - TipRanks.com - TipRanks - February 18th, 2024
- Revolutionizing Gene Therapy: A Novel Technique for In Vivo CAR T Cells - Medriva - February 18th, 2024
- How Stella Vnook is 'infusing innovation' into cell therapies with Likarda's technology - BioPharma-Reporter.com - February 18th, 2024
- Using cancer's 'superpower' to boost T-cell therapies in mice - FierceBiotech - February 18th, 2024
- Parkinson's Disease Patient Identification and Education Will Need to Improve When New Disease Modifying ... - Yahoo Finance - February 18th, 2024
- CRISPR (CRSP) to Report Q4 Earnings: What's in the Cards? - Yahoo Finance - February 18th, 2024
- Gene Therapy: A Ray of Hope for Heart Failure Treatment | Health News - Medriva - February 18th, 2024
- Gene therapy trials restore hearing to children born deaf - The Hill - February 2nd, 2024
- Early Trial Success for Inherited Deafness Gene-Therapy - RegMedNet - February 2nd, 2024
- Sickle cell gene therapy first focus of Medicaid pay model - Modern Healthcare - February 2nd, 2024
- Beyond chemotherapy: Navigating the promise and perils of CAR-T therapy in pediatric cancer - BioPharma-Reporter.com - February 2nd, 2024
- Angiodema: Gene therapy blocks painful hereditary disorder - BBC - February 2nd, 2024
- FDA: Genome editing therapies may use accelerated approval pathway - Regulatory Focus - February 2nd, 2024
- CRISPR tech treats severe hereditary condition successfully - Interesting Engineering - February 2nd, 2024
- Gene Therapy Restores Hearing in Small Trial for Kids With Hereditary Deafness - Technology Networks - February 2nd, 2024
- Gene-based therapy may slow development of life-threatening heart condition - Medical Xpress - February 2nd, 2024
- Jaguar Gene Therapy Announces FDA Clearance of IND to Study JAG201 in a Genetic Form of Autism Spectrum ... - Business Wire - February 2nd, 2024
- Replacing the PKP2 gene prolongs survival in ARVC patients - Drug Target Review - February 2nd, 2024
- Cell and gene therapies top pharmaceutical industry trend to watch for 2024 - Pharmaceutical Technology - February 2nd, 2024
- Gene Therapy Restores Hearing in Children with Hereditary Deafness - The Hearing Review - February 2nd, 2024
- 2 Dutch among 10 "functionally cured" of hereditary swelling disease by new gene therapy - NL Times - February 2nd, 2024
- FDA publishes final industry guidance for CAR-T and gene therapies - PMLiVE - February 2nd, 2024
- Gene therapy cures hereditary deafness in two people - Advanced Science News - February 2nd, 2024
- Hearing Restored in Deaf Children in Gene Therapy Clinical Trial - Securities.io - February 2nd, 2024
- Vivet Therapeutics Receive 4.9 Million to Advance Development of Gene Therapy - European Pharmaceutical Manufacturer - February 2nd, 2024
- Adverum Biotechnologies will Host Webcast to Review LUNA Phase 2 Preliminary Efficacy and Safety Results on ... - GlobeNewswire - February 2nd, 2024
- Allogene parks Notch CARs, leaving one on the road - FierceBiotech - February 2nd, 2024
- Experimental gene therapy allows kids with inherited deafness to hear - The Associated Press - January 25th, 2024
- Gene-therapy breakthrough allows congenitally deaf children to hear Harvard Gazette - Harvard Gazette - January 25th, 2024
- Gene therapies restore hearing in several kids with inherited deafness - Livescience.com - January 25th, 2024
- Boy born deaf can hear for the first time thanks to a gene therapy procedure - NBC 6 South Florida - January 25th, 2024
- Gene therapy restores hearing in children with hereditary deafness - Medical Xpress - January 25th, 2024
- Children's Hospital of Philadelphia Performs First in U.S. Gene Therapy Procedure to Treat Genetic Hearing Loss - PR Newswire - January 25th, 2024
- Children's Hospital of Philadelphia uses gene therapy to help 11-year-old boy hear for 1st time - WPVI-TV - January 25th, 2024
- Breakthrough gene therapy treatment restores hearing in children born deaf - The Independent - January 25th, 2024
- Gene Therapy Administered Via Virus Cures Deafness in 11-Year-Old Boy - Futurism - January 25th, 2024
- 11-Year-Old Boy Hears For First Time Ever Thanks To Gene Therapy Breakthrough - IFLScience - January 25th, 2024
- Gene Therapy Deafness | National | caledonianrecord.com - The Caledonian-Record - January 25th, 2024
- Sickle cell gene therapy to be covered by Blue Cross insurers - Modern Healthcare - January 25th, 2024
- Experimental gene therapy allows kids with inherited deafness to hear - Jackson Hole News&Guide - January 25th, 2024
- Gene therapy allows 11-year-old boy to hear for the first time - Latest From ITV News - ITVX - January 25th, 2024
- Experimental Gene Therapy Allows Kids With Inherited Deafness To Hear - Southern Minnesota News - January 25th, 2024
- Joint US-China gene therapy trials restore hearing in 5 kids, a first - Interesting Engineering - January 25th, 2024
- Gene Therapy Deafness | Nation | The Daily News - Galveston County Daily News - January 25th, 2024
- In Draft Guidance for Cell and Gene Therapy Industry, FDA Broadens its Approach to Product Potency - Precision Medicine Online - January 25th, 2024
- Gene therapy helps restore hearing in children with hereditary deafness - Shropshire Star - January 25th, 2024
- Gene therapy breakthrough enables deaf boy to hear for the first time - The Week - January 25th, 2024
- FDA eyes collaborative review pilot for gene therapies - Regulatory Focus - January 17th, 2024