March 27, 2026 —
Rocket Pharmaceuticals has received accelerated approval from the U.S. Food and Drug Administration (FDA) for Kresladi, a gene therapy designed to treat severe leukocyte adhesion deficiency type 1 (LAD-I), a rare and life-threatening inherited immune disorder.
LAD-I is caused by mutations that impair the immune system’s ability to fight infections. Infants born with the disease often experience severe bacterial and fungal infections, leading to frequent hospitalizations. Without treatment, survival typically requires a bone marrow transplant, which is not available or feasible for all patients. Kresladi is indicated for children whose disease is caused by specific genetic mutations and who are unable to receive a transplant.
Kresladi is based on an ex vivo gene therapy approach, where a patient’s own hematopoietic stem cells are collected and genetically modified using a viral vector to deliver a functional copy of the defective gene before being returned to the patient. Ex vivo approaches like Kresladi modify cells outside the body before reinfusion, enabling long-term correction of immune cell function.
In clinical testing, Kresladi demonstrated the ability to dramatically reduce severe infections, while helping patients remain alive and out of the hospital. However, the FDA noted that longer-term follow-up will be required to confirm the durability of the therapy’s clinical benefits as part of ongoing studies.
The most commonly reported side effects included anemia, low platelet counts, reduced white blood cell counts, and mouth sores, which are generally associated with the conditioning regimens used in stem-cell-based gene therapies.
In announcing the approval, FDA officials described Kresladi as a breakthrough treatment for patients with LAD-I, highlighting the agency’s flexibility in evaluating therapies for ultra-rare diseases where patient populations are extremely small.
The approval represents a significant milestone for Rocket Pharmaceuticals, marking the company’s transition into a commercial-stage gene therapy developer after several years of operational and financial challenges. The company previously faced regulatory setbacks when the FDA rejected Kresladi in 2024 due to manufacturing concerns, and additional pipeline issues led to layoffs and restructuring efforts.
At its peak in 2021, Rocket Pharmaceuticals had a market capitalization exceeding $3 billion, driven by its pipeline of ex vivo and in vivo gene therapies targeting rare diseases. However, subsequent clinical and regulatory challenges significantly reduced investor confidence, causing the company’s valuation to decline sharply.
Although Kresladi is expected to serve a relatively small patient population—LAD-I affects roughly 1 in 100,000 to 200,000 births in the United States—the approval carries additional financial benefits for Rocket. The therapy qualifies for a Priority Review Voucher (PRV), which the company may sell to other pharmaceutical developers. Such vouchers have historically been sold for hundreds of millions of dollars, potentially providing important funding to support Rocket’s broader pipeline.
The company is currently evaluating options to monetize the PRV, which could extend its operational runway beyond 2027 and support continued development of its pipeline, including a cardiovascular gene therapy program currently in pivotal clinical testing.
While Kresladi may not become a blockbuster therapy due to the rarity of LAD-I, its approval highlights the continued progress of gene therapies targeting severe genetic diseases and underscores the growing impact of advanced genetic medicine in treating conditions that previously had few effective treatment options.
