What is gene therapy?

Gene therapy refers to a wide range of medical interventions that use genetic material to treat disease. It relies on delivery vehicles such as inert viruses and spheres of lipids to insert healthy genes where they’re missing. People with hemophilia A carry a mutation that prevents their blood from clotting properly, leading to sudden uncontrolled bleeding. The disease can make basic activities such as playing sports potentially life-threatening. Roctavian , which is delivered intravenously, sends neutralized viruses to a patient’s liver. The virus then inserts the gene that provides instructions for producing a protein to clot blood. Scientists sometimes make a distinction between gene therapy, which introduces healthy genetic material, and gene editing , which tweaks existing genes. The FDA has approved therapies from the first category, not the second.

What gene therapies have regulators approved?

The FDA first approved a gene therapy in 2017. Kymriah was a treatment for a form of leukemia. The agency has since approved more than 30 cellular- and gene-based treatments, including Roctavian. Some are manufactured by pharmaceutical megaliths such as Novartis, and others by start-ups that specialize in genetic technology . Regulators receive hundreds of requests to approve new gene therapies each year, which has posed problems for the FDA office charged with evaluating them. Last year, Wilson Bryan, then an FDA official, said at a gene therapy conference that the influx of new proposals had overloaded his office, which deals with gene and tissue therapies. “We are all trying to help patients,” Bryan said in May 2022 , before he retired from the agency this year. “There is just this huge need. The rapid growth in the development of cell and gene therapies has created challenges for us.”

Why is gene therapy so expensive?

Available gene therapies treat rare diseases, and potential patients can number in the thousands or fewer. Private companies often spend hundreds of millions of dollars shepherding a therapy through the research and approval process. They must set eye-watering prices if they aim to profit from products that will be sold to relatively few customers. It also means gene therapies are often too expensive for the patients they could help, said Fyodor Urnov , a genetics professor at the University of California at Berkeley. He sees several paths to lowering the cost of gene therapies. The field is new, and the infrastructure to produce treatments may get cheaper. There’s also a need for “academic, nonprofit paths to developing and delivering” genetics-based medicine, Urnov said. He and his colleagues regularly receive emails from parents of patients with rare genetic diseases who are desperate for treatment but can’t afford it. “We haven’t really built a system that spreads the public health joy equitably,” Urnov said. “It’s a large open question.”

Are there ethical issues with gene therapy?

Gene therapy raises some of the same worries as other genetic research such as stem cell biology and cloning. In particular, bioethicists are wary of any changes to sperm and egg cells that might pass changed genes from parent to child. Since 2016, federal law has prohibited the FDA from accepting applications “in which a human embryo is intentionally created or modified to include a heritable genetic modification.”

What’s the future of gene therapy?

Researchers studying gene therapies have initially focused on rare disorders because they often lack other treatment options. The technology could have much broader uses, though, said David Liu , a professor of chemistry at Harvard University. “The ability to change our DNA and the DNA of other organisms is a very fundamental capability, broadly applicable beyond rare diseases,” Liu wrote in an email to The Washington Post. As scientists assess the effects of gene therapy and gene editing over the next several years, the techniques may expand to address more than rare diseases. Potential applications of gene editing could include treatments for cancer, high cholesterol and unhealthy weight, said Omar Abudayyeh , who co-runs a cellular engineering lab at Massachusetts Institute of Technology’s McGovern Institute. In the near term, the FDA is considering the first treatments that would use Vertex Pharmaceutical’s CRISPR tool to edit, rather than just insert, genetic material. The company expects the agency to approve or deny those therapies, which could treat sickle cell disease and beta thalassemia, by March 2024.

The FDA just approved another gene therapy. Here’s what to know about them.

By Shera Avi-Yonah

Updated July 5, 2023 at 4:20 p.m. EDT|Published July 1, 2023 at 8:00 a.m. EDT

Roctavian, the new gene therapy approved by the Food and Drug Administration Thursday, treats hemophilia A. (Manuel Balce Ceneta/AP)

5 min

The Food and Drug Administration on Thursday approved a treatment that uses gene therapy to treat severe hemophilia A, a rare and sometimes fatal blood disorder.

The new drug, Roctavian, could save people with the severe form of the disease from a lifetime of frequent injections. The drug’s maker expects about 2,500 of the estimated 6,500 Americans with severe hemophilia A to be eligible to receive the drug with its initial approval.

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The treatment uses a single infusion to insert the genes people with hemophilia A are missing, and may work for years, according to data presented to regulators. It’s also the latest FDA-approved gene therapy, heralding what some scientists say is the future of treating thousands of diseases.

The FDA has approved gene therapies for conditions including spinal muscular atrophy. Use of the technology is relatively rare, in part because gene therapies are among the most expensive drugs in the world. Roctavian will cost $2.9 million for a single infusion; Hemgenix, which treats another form of hemophilia, costs $3.5 million per use, according to Reuters. Still, scientists say the technology will be a crucial part of 21st century medicine.

Here’s what you need to know.

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