The Future of Gene Therapy: From Rare Cures to Ordinary Medicine

The U.S. Food and Drug Administration granted accelerated approval on April 23, 2026, to Otarmeni, a gene therapy designed to treat severe-to-profound hearing loss caused by mutations in the OTOF gene. Developed by the pharmaceutical company Regeneron, the treatment represents a significant milestone in the ability to reverse certain types of congenital deafness.

The approval follows an international clinical trial conducted by Mass Eye and Ear and China’s Fudan University. In a pivotal trial for the drug, 80 percent of treated patients gained measurable hearing, while 42 percent reached a level of hearing sufficient to pick up whispers. Data from the underlying multi-center trial indicated that 90 percent of patients were still hearing two and a half years after receiving the treatment.

The real-world impact of the therapy has been documented in clinical settings. In one instance, a toddler born deaf showed no reaction to sound in a lab environment; six weeks after a single injection of the experimental therapy, the child responded to a tone and turned toward the sound of a family member’s voice.

“When the parents realized their child had a response to sound they cried. The whole family cried.”

Dr. Yilai Shu, Eye & ENT Hospital of Fudan University

Recovery from a historical collapse

The success of therapies like Otarmeni follows a period of extreme volatility for the field of gene therapy. In 1999, the industry nearly collapsed after Jesse Gelsinger, a teenager, died four days after receiving an experimental gene therapy at the University of Pennsylvania. This event marked the first publicly identified death in a gene therapy clinical trial.

The aftermath of Gelsinger’s death led the FDA to halt gene therapy trials in the United States and the National Institutes of Health to tighten oversight. James Wilson, the principal investigator of the Penn study, was stripped of his administrative titles and barred from clinical trials for five years.

The field eventually recovered through two primary advancements. First, researchers shifted delivery methods. The therapy administered to Gelsinger used an adenovirus, which is highly immunogenic and can trigger violent immune responses. Modern therapies, including Otarmeni, utilize adeno-associated viruses (AAV), which are smaller and more tolerable to the human immune system.

Second, the adaptation of CRISPR in 2012 by Jennifer Doudna and Emmanuelle Charpentier provided a precision gene-editing tool. Unlike AAV, which delivers a working copy of a gene, CRISPR can find a specific location in a patient’s DNA and rewrite the genetic code to correct a broken gene in place.

An expanding list of approvals

Since the recovery of the field, the FDA has cleared a growing number of gene therapies for inherited diseases:

• Luxturna: Approved in December 2017 for hereditary blindness resulting from RPE65 mutations.
• Zolgensma: Approved in 2019 for spinal muscular atrophy.
• Hemgenix: Approved in 2022 for hemophilia B.
• Casgevy and Lyfgenia: Approved in 2023 for sickle cell disease, with Casgevy being the first FDA-approved CRISPR therapy.

The sickle cell approvals are particularly notable as they target a larger patient population, with 100,000 Americans suffering from the disease. Other applications are currently in development, including Verve Therapeutics’ use of base editing to disable the PCSK9 gene to lower LDL cholesterol. Early trial data for that treatment showed a 53 percent average drop in LDL cholesterol.

Economic and ethical challenges

Despite the scientific progress, the cost of these treatments remains a significant barrier. Recent approvals carry high list prices: Luxturna is priced at $850,000 per patient, Zolgensma at $2.13 million, Casgevy at $2.2 million, Lyfgenia at $3.1 million, and Hemgenix at $3.5 million.

Regeneron has pledged to provide Otarmeni for free in the United States. This is possible because the target patient pool is small, estimated at 50 babies per year. However, such a model is not sustainable for more common disorders.

Beyond cost, the application of gene therapy to infants raises ethical and cultural concerns. Within Deaf culture, some argue that deafness should be viewed as an identity rather than a deficit, a debate that has existed regarding cochlear implants since the 1980s. Because infants cannot consent to gene therapy, the decision rests entirely with parents.

current gene therapy is limited to single-gene disorders. It cannot yet treat polygenic conditions—those caused by multiple genes—such as schizophrenia or Alzheimer’s disease. While the technology is effective for small, accessible targets like the cochlea, the complexity of the brain remains a significant hurdle for the next decade of medical research.