FDA Clears Way for Trial of Gene Editing Therapy for Severe SCD

The U.S. Food and Drug Administration (FDA) has cleared the initiation of a Phase 1/2 trial investigating EDIT-301, Editas Medicine’s experimental gene editing cell therapy for  sickle cell disease (SCD).

The planned open-label study, to be called RUBY, will assess the safety and efficacy of a single dose of EDIT-301 in patients with severe SCD.

“The FDA’s clearance for initiation for our EDIT-301 clinical trial is an exciting moment for us and the patients we hope to serve. We look forward to bringing this potentially best-in-class, one-time, durable medicine into the clinic and to patients,” Cindy Collins, president and CEO of Editas Medicine, said in a press release.

The FDA clearance, however, applies only to the therapy being testing in the study’s safety phase.

An improved potency assay must be developed by the company and submitted to the U.S. agency for review before the trial can begin enrolling patients into its efficacy phase. Usually, treatment effectiveness is investigated once safety is shown in a first patient group.

Potency assays are tests, often requested by regulatory health authorities, to evaluate the ability a treatment to induce a specific effect when given at a particular dose.

Editas reported that it has started preparations to launch RUBY, including identifying a principal investigator to lead the study and engaged a clinical research organization to support its regulatory procedures.

EDIT-301 is an experimental one-time gene editing cell therapy that modifies a patient’s blood cell precursors (hematopoietic stem cells) to increase the production of fetal hemoglobin in red blood cells. Fetal hemoglobin, a version of hemoglobin found in newborns, is more efficient at transporting oxygen than its adult counterpart. 

This experimental therapy, which edits cells taken from a patient before being returned to them, is the first to use the gene editing tool CRISPR/Cas12a (also known as CRISPR-Cpf1) and targets two regions in the genome, the HBG1 and HBG2 promoters. 

By increasing the production of fetal hemoglobin, EDIT-301 may provide long-term benefits to those with SCD, including improved blood flow and fewer pain crises.

“We know patients are counting on us, and we believe EDIT-301 has the potential to transform the lives of people living with sickle cell disease, addressing a significant unmet need,” Collins said.

The FDA granted rare pediatric disease designation to EDIT-301, a status given to investigative therapies for serious or life-threatening conditions affecting fewer than 200,000 people in the U.S., and mainly those under age 18.