Cell and gene therapies that provide patients with a long-term effect from a single dose are more than twice as likely to win FDA approval than other treatments. But despite their regulatory successes, several of these medicines are struggling commercially.
A recent study published in Nature Reviews Drug Discovery analyzed hundreds of clinical trials going back decades found that these therapies have a 19 percent FDA approval rate, more than double the average. Since the FDA approved the first therapy in this class in 2017, the agency has greenlit more than 30.
Because these treatments typically target the genetic root cause of disease, they generally provide clear clinical results for regulators to review. But few of these therapies have seen widespread adoption due to commercial and competitive challenges. Even drugs that demonstrate efficacy in clinical trials may not be developed by drug companies – for instance, the study notes that three sickle cell disease drug trials were discontinued in 2023, likely because competitors were slated to get approval ahead of them.
“A technical clinical trial success may fail by not securing funding for initiating the next
Phase,” the study authors wrote “In our judgment [durable cell and gene therapies] have experienced a higher-than-average strategic failure rate in 2022 and 2023, but despite the funding challenges, have maintained higher success rates compared to other therapeutic modalities.”
Take Hemgenix, the $3.5 million treatment for hemophilia B, approved by the FDA in late 2022, based on clinical trials that showed patients saw a more than 50 percent decline in annual bleeding rates 18 months after infusion. Yet by mid-2024, only a dozen or so patients had received treatment with the medicine.
In February 2025, Pfizer announced it was discontinuing its own hemophilia drug Beqvez, less than a year after winning FDA approval, due to several factors including limited interest from patients and doctors.
Casgevy and Lyfgenia, two gene therapies for sickle cell disease, received approval by from the FDA in December 2023. As of early 2025, the number of treated patients remains small. Both therapies require hospital systems to become specially certified before they can administer the treatment—a process that includes staff training, facility upgrades, and coordination across multiple departments.
Commercial Challenges Thwart CGTs Access
The commercial challenges faced by CGTs are widespread. According to a sector snapshot by the Alliance for Regenerative Medicine, only two cell and gene therapies — for spinal muscular atrophy, and Yescarta, for large B-cell lymphoma — have reached blockbuster status, generating more than $1 billion annually. Three others—Carvykti, for multiple myeloma, Elevidys, for Duchenne muscular dystrophy, and Breyanzi, for certain types of large B-cell lymphoma — are approaching that milestone, but the majority fall short.
Reimbursement has also played a role. High price tags and complex care requirements have led to cautious rollout strategies and narrow coverage policies. Some hospitals have delayed offering the treatments altogether, citing concerns about upfront costs, care coordination and long-term follow-up.
Even therapies with strong clinical results face barriers to access. These include payer uncertainty, limited treatment infrastructure and the time-intensive nature of one-time procedures that require cell harvesting, genetic modification and re-infusion.
CGTs Vying for Approval in 2025
Still, the commercial challenges haven’t deterred drug developers. Several more cell and gene therapies are slated for FDA review and potential approval this year, targeting conditions including Hunter syndrome, Sanfilippo syndrome, recurrent respiratory papillomatosis, and other rare genetic and neuromuscular diseases.
Some of these therapies would be first-in-class drugs, and aimed at patients with few or no existing treatment options, and their progress will offer further insight into whether regulatory momentum can be matched by real-world access.