Sickle Cell Gene Therapies Offer New Hope, but Access Remains a Major Challenge

The therapies have shown curative potential. Gene therapy has been shown to achieve a high rate of efficacy, with 88% to 94% of patients experiencing complete freedom from severe vaso-occlusive crisis. Dr. Edward Donnell Ivy, chief medical officer for the national patient advocacy organization Sickle Cell Disease Association of America, said, “That opens up a whole world of individuals potentially being cured of sickle cell disease.” Ivy, who is also a sickle cell disease patient, said bone marrow transplant was always available but was not a great option because not too many people had access to a donor. “Now that we have the cell and gene therapies, an individual can act as their own donor,” he said.

Access, however, is uneven. CNBC reported that patients often face a fragmented healthcare landscape in which treatment costs, a complex treatment process, provider availability, and access to specialized treatment centers can vary widely based on where they live. The result has left therapies with the potential to dramatically alter the course of the disease still out of reach for many eligible patients. Dr. Alexias Thompson, an attending physician in the division of hematology at Children's Hospital of Philadelphia and spokesperson for the American Society of Hematology, said, “The patients' priorities are actually a big part of really trying to figure out what the barriers to access are and how we overcome them.”

Sickle cell disease is a genetic blood disorder that causes normally flexible, round-shaped red blood cells to become rigid and crescent-shaped, which can block blood vessels and reduce oxygen delivery to tissues. It affects around 100,000 people in the U.S., according to the Centers for Disease Control and Prevention, and more than 90% of the patient population are non-Hispanic Black or African American. Sometimes called “the most common rare disease” because millions of people globally are affected, it can shorten life expectancy by up to 20 years. Common complications include chronic fatigue and anemia, blood clots, vaso-occlusive or “pain” crises that can last from a few hours to several weeks, stroke, organ damage and increased risk of infection.

Progress in treatment was slow for decades. More than a century after the first documented U.S. case in 1910, new treatment development remained limited, due in part to decades of underinvestment and lower philanthropic support than other rare genetic disorders received. From 2008 through 2018, National Institutes of Health research funding for sickle cell disease averaged $812 per patient, according to a 2020 analysis. By comparison, funding for cystic fibrosis, which affects approximately 40,000 people in the U.S., averaged $2,807 per patient over the same period.

Dr. Andrew Campbell, director of the comprehensive sickle cell disease program at Children's National health system in Washington, D.C., said, “There's been a slow increase in the development of new therapies for sickle cell disease. In the past six or seven years, there's been an explosion in that, but I would say from 1910 until about 2015, there was very little progress in disease-modifying treatments for sickle cell disease.”

A major breakthrough arrived in 1998 with FDA approval of hydroxyurea, the first medication shown to modify the health effects of sickle cell disease. Studies found the drug helped reduce the frequency of pain crises in patients by half, as well as the need for hospitalizations and blood transfusions. Hydroxyurea has since become a cornerstone of treatment, helping thousands manage their condition. Yet a curative treatment remained elusive until gene therapy. For years, the only option was a bone marrow transplant, limited to a select number of patients able to find a donor match.

Despite the curative potential of gene therapies, uptake has been slow. By the end of 2025, a total of 64 patients worldwide had received the therapies, CNBC reported.