BY THE OPTIMIST DAILY EDITORIAL TEAM

For children born with ADA-SCID, a rare genetic disease that severely compromises the immune system, everyday germs can be fatal. ADA-SCID (short for severe combined immunodeficiency due to adenosine deaminase deficiency) leaves the body unable to fight off infections. Untreated, many children do not survive past age two.

A life-threatening diagnosis, a life-saving breakthrough

But hope has arrived in the form of an ingenious gene therapy. In a study recently published in The New England Journal of Medicine, an experimental treatment saved the lives of 62 children diagnosed with ADA-SCID. The therapy, administered in just a single dose, has shown a remarkable 100 percent survival rate in patients followed for more than a decade.

Among them is Eliana Nachem, who received the therapy ten years ago. Her father, Jeff, recalls how their family had to isolate completely to protect her. “My wife didn’t leave the house, I had to shower and change clothes before I could even hold Eliana,” he shared. Now, Eliana is thriving: she plays basketball, sings in the school choir, and is thriving at school. “It’s incredible,” Jeff said.

How the therapy works

The therapy works by extracting blood stem cells from a child, inserting a healthy copy of the faulty ADA gene using a lentivirus, and reinfusing the modified cells into the body. This treatment gives these isolated children a working immune system, and the chance at a liberated childhood.

“To me, cure means a lifelong absence of disease,” said Dr. Donald Kohn of UCLA, who led the research. “We can’t say that definitively yet, but the clinical benefits have remained stable over 7 to 12 years.”

Unlike earlier treatments such as weekly enzyme injections or risky bone marrow transplants, this approach may offer a safer and more lasting solution. Kohn’s team has also improved the process by freezing the altered cells, allowing treatments to be shipped and administered globally, offering an important step toward broader access.

Cost, access, and the challenge of rare diseases

Despite its promise, the therapy comes with a hefty price tag—up to one million euros per treatment. While the cost is steep, Dr. Kohn noted that current enzyme therapies are also expensive and must be continued for years. “So within a few years after the ‘one and done’ gene therapy, the overall costs should be less,” he said.

Similar gene therapies, like Strimvelis, have also shown strong results but struggled with commercialization. Developed in Milan and approved in 2016, Strimvelis was eventually dropped by its pharmaceutical backers due to financial challenges. The Telethon Foundation now maintains its availability.

Safety remains a concern, too. One child treated with Strimvelis developed leukemia from unintended DNA changes. The new therapy, however, uses lentiviruses rather than retroviruses and has not shown such side effects to date.

Juan Antonio Bueren of CIEMAT in Madrid praised the results but cautioned about cost barriers. “There is a problem with commercializing gene therapies for rare diseases,” he said. “They require extensive production and long-term monitoring, making them very expensive.”

A path forward for future therapies

Though commercialization has stalled in the past, momentum is building. Kohn and colleagues founded a company, Rarity PBC, to bring the therapy to more families. With a $14.7 million grant from the California Institute for Regenerative Medicine, they are developing scalable production methods.

So far, lentivirus-based therapies have shown potential in treating around 15 rare diseases. But as Bueren notes, pricing models remain a challenge, especially in public health systems across Europe.

Despite these hurdles, families and researchers alike remain hopeful. “I don’t know what’s fair to charge,” said Jeff Nachem, “but this kind of treatment shouldn’t be denied to a small child who needs it to survive.”

This latest success is more than a medical milestone; it’s a testament to what’s possible when science, persistence, and compassion converge. For dozens of children once confined to sterile rooms and a life of fear, it’s not just a treatment. It’s the freedom to live.

Source study: The New England Journal of Medicine—Long-term safety and efficacy of gene therapy for adenosine deaminase deficiency