FDA Names Potential Gene Therapy for Sickle Cell an ‘Orphan Drug,’ Aruvant Announces

A potential gene therapy for sickle cell disease (SCD) and beta-thalassemia, known as ARU-1801, has been named an  orphan drug by the U.S. Food and Drug Administration (FDA), a status that helps to advance and support its development.

The FDA recently also designated ARU-1801 a potential rare pediatric disease treatment for these same two blood disorders, allowing for priority review.

“We are excited to build on the momentum afforded by both today’s announcement of Orphan Drug status as well as our recent announcement of Rare Pediatric Disease status for ARU-1801,” Will Chou, MD, chief executive officer of Aruvant, which is developing the therapy, said in a press release.

ARU-1801 aims to increase the number of functional red blood cells by inserting a modified version of the fetal hemoglobin gene directly into the patients’ own stem cells, via a viral vector called a lentivirus. This gene provides instructions to make a protein called fetal hemoglobin, whose production normally takes place prior to birth.

Fetal hemoglobin is more effective at transporting oxygen than the version of the hemoglobin protein found in adults.

In this way, ARU-1801 is expected to lessen the number of painful vaso-occlusive crises (VOCs), often requiring  hospitalization, in people with these disorders, and to improve their overall health and quality of life.

An open-label Phase 1/2 trial (NCT02186418) investigating the safety, feasibility and efficacy of ARU-1801 in up to 10 adults with sickle cell is underway in the U.S., Canada, and Jamaica. This study may still be recruiting eligible patients, ages 18 to 45. Contact and other information on these sites can be found here.

Unlike some other forms of gene therapy, ARU-1801 is compatible with a reduced intensity conditioning (RIC) regimen. These conditioning regimens — involving chemotherapy and/or radiotherapy — are given patients prior to the therapy to clear their system of “defective” blood-forming cells and prepare it for the introduction of the genetically modified cells.

RIC is a conditioning regimen that uses low-intensity chemotherapy and/or radiotherapy, and for that reason is associated with fewer and less severe side effects compared to more high-intensity (myeloablative) regimens.

“For patients suffering from sickle cell disease, we believe the ultimate promise of gene therapy is a one-time cure without the side effect profile of high intensity myeloablative conditioning,” Chou said.

“We are committed to providing patients with that option and look forward to presenting more data  … as patients continue to be treated in our ongoing Phase 1/2 study,” he added.

Orphan drug status is given to support investigative treatments for rare diseases, defined in the U.S. as disorders that affect fewer than 200,000 people.

The designation comes with certain benefits, including financial incentives for drug development and commercialization, U.S. market exclusivity for seven years following approval, FDA support for clinical studies, and fee exemptions and reductions.