Gene Therapy RP-L201 Shows Promise in Pediatric LAD-I Cases in Phase 1/2 Results

New phase 1/2 data suggest a lentiviral-mediated ex-vivo gene therapy is safe and associated with durable neutrophil CD18 expression, as well as other clinical improvements, in patients with rare genetic disorder Leukocyte Adhesion Deficiency-I (LAD-I).

In new findings presented at the American Society of Hematology (ASH) 2021 Meeting in Atlanta this weekend, investigators from Rocket Pharmaceuticals shared interim analysis of 7 pediatric patients administered RP-L201 stem cell transplants. As study author Donald B. Kohn, MD, of the University of California, Los Angeles, told HCPLive during ASH 2021, the results thus far yield great promise.

“I think the results are exciting and encouraging,” Kohn said. “At this point, we’re batting 1.000.”

To date, Kohn said, all post-transplant patients reported in the phase 1/2 trial data are continuing monitoring and care.

“And the majority who are beyond 6 months or more have been able to stop all their prophylactic antibiotics that they’ve been on for years and years, and we’ve had no serious LAD-I type infections in the patients after the gene therapy,” he explained.

Kohn shared the clinical manifestations of LAD-I: severe, chronic infections of the skin, pulmonary system, or otherwise. “It’s a primary immune deficiency disease; it’s genetic, it’s autosomal recessive, it’s quite rare, and the effect on patients is really quite a severe disease burden of infections,” Kohn said.

Kohn also discussed the limited current state of available therapies for the rare pediatric population, which includes continual antibiotics for skin lesions, hematopoietic stem cell transplant therapy—which has the opportunity to be curative—and interleukin 12 and 23 (IL-12; IL-23) targeting biologic therapies including ustekinumab, which has a “remarkable effect on helping these lesions regress.”

“That would be a temporizing measure but can improve the status of the patient when, for example, going to transplant,” he explained.

The study, “A Phase 1/2 Study of Lentiviral-Mediated Ex-Vivo Gene Therapy for Pediatric Patients with Severe Leukocyte Adhesion Deficiency-I (LAD-I): Interim Results,” was presented at ASH 2021.