Kresladi Receives FDA Nod as First Gene Therapy for Rare Genetic Immune Disorder

The FDA has approved the first gene therapy for severe leukocyte adhesion deficiency type I (LAD-I), a rare and often fatal genetic immune disorder that primarily affects children. 

The therapy, developed by Rocket Pharmaceuticals and branded as Kresladi, marks a major milestone in the treatment of inherited immunodeficiencies as a potential one-time alternative to high-risk stem cell transplantation.

LAD-I is caused by mutations in the ITGB2 gene, which impairs the ability of white blood cells to adhere to blood vessel walls and migrate to sites of infection. As a result, patients are highly vulnerable to recurrent, severe infections.

Without treatment, the disease is often fatal early in life. Historically, the only curative option has been an allogeneic hematopoietic stem cell transplant, which carries significant risks and requires a suitable donor.

The FDA’s approval of Kresladi represents the first therapy specifically approved for LAD-I, addressing a major unmet need in this ultra-rare population.

Along with the approval, Rocket has also secured a rare pediatric disease priority review voucher from the FDA, which the company plans to sell to support its R&D initiatives. 

Kresladi is an autologous gene therapy, meaning it uses a patient’s own cells. The process involves collecting hematopoietic stem cells from the patient, using a lentiviral vector to insert a functional copy of the defective gene and reinfusing the corrected cells back into the patient.

Once infused, these modified cells can produce functional immune cells capable of responding to infections, potentially providing a durable, long-term benefit after a single treatment.

The FDA granted approval based on clinical data showing meaningful improvements in immune function, including biomarkers associated with the ability of white blood cells to reach infection sites, namely levels of CD11a and CD18 on the surface of neutrophils.

In earlier studies, all treated patients survived for at least one year post-treatment.

Given the rarity and severity of LAD-I, the therapy was approved under an accelerated pathway, which allows earlier approval based on surrogate endpoints reasonably likely to predict clinical benefit.

Confirmatory data will be required as the approval was granted through the FDA’s accelerated pathway. Rocket Pharmaceuticals said confirmation of clinical benefit will be based on the evaluation of longer-term follow-up data of treated patients in the ongoing clinical study and through a post-marketing registry.

“The approval of Kresladi represents an important milestone for the severe LAD-I community,” said Gaurav Shah, MD, Chief Executive Officer, Rocket Pharmaceuticals. “This approval reflects the dedication of patients, families, investigators and regulators who have worked together to advance research of this ultra-rare disease. We look forward to making Kresladi available to eligible patients in the United States.”

Rocket Pharmaceuticals plans a phased launch beginning in late 2026, focusing initially on a small number of specialized treatment centers.

According to reporting by Fierce Pharma, Shah said on a Friday investor call that the company plans a “minimal viable launch” for the therapy. He explained that Rocket will make Kresladi available to patients and physicians who seek it out, while holding back on major marketing efforts and large-scale commercialization, reserving those resources for its newer cardiovascular programs.

In the US, about 25 children are born with LAD-1 every year, and approximately two-thirds have the severe form of the disease. 

Rocket did not disclose pricing or access details, with executives saying more information will come ahead of Kresladi’s planned fourth-quarter launch. The company expects the first patient infusion, and initial revenue, in 2027.

While Kresladi may not be a commercial priority, the approval is nonetheless being seen as a win in the field. Tim Hunt, CEO of the Alliance for Regenerative Medicine, called it “welcome news” for patients and the broader cell and gene therapy sector, expressing hope it signals a more patient-centric era at the FDA.

Analysts at Jefferies said in a note that while the launch represents a relatively small commercial opportunity, the approval helps “de-risk” Rocket’s gene therapy platform and supports future product approvals.

In recent years, the FDA has increasingly used flexible regulatory pathways to accelerate treatments for conditions with high unmet need and small patient populations, which has accelerated under the Trump administration. 

Earlier this year, the FDA issued new guidance outlining how sponsors can generate evidence for individualized therapies when traditional randomized controlled trials aren’t feasible due to extremely small patient populations, emphasizing biological rationale, natural history data and alternative evidence to support safety and effectiveness. 

Rocket began shifting its strategy last summer after a patient death in a gene therapy trial earlier in 2025. In July, the company announced a 30% workforce reduction and narrowed its focus to cardiovascular programs.

At the end of 2025, Rocket held $188.9 million in cash and investments, which Shah expects will fund operations into mid-2027, potentially extending into 2028 with the sale of its priority review voucher.

Rocket first submitted Kresladi for FDA review in late 2023 but was initially turned away due to requests for additional manufacturing data.