Researchers presented the results of a new study at this year’s American College of Allergy, Asthma, and Immunology (ACAAI) annual scientific meeting in Louisville, KY, that shows a treatment using CRISPR genome editing technology succeeded in alleviating swelling and reducing the frequency in attacks of hereditary angioedema (HAE). HAE is a rare, genetic disorder characterized by severe, recurring, and unpredictable swelling attacks in various organs and tissues of the body, which can be painful, debilitating, and life-threatening.

A C1-inhibitor test is used to diagnose hereditary angioedema. [Md Ariful Islam/Getty Images]
“NTLA-2002 is a one-time, systemically administered CRISPR genome editing candidate being developed for HAE,” said clinical immunologist Hilary Longhurst, MD, PhD, senior medical officer (immunology) at the Auckland Distract Health Board and hon. associate professor at Auckland University. “It is designed to knock out the KLKB1 gene in liver cells, thereby reducing the production of a specific protein called kallikrein whose uncontrolled activity is responsible for the recurring, debilitating, and potentially fatal swelling attacks that occur in people living with HAE.”

The interim clinical data from the Phase I first-in-human study of NTLA-2002, which is being developed by Intellia Therapeutics, involved patients with HAE (both males and females) treated to date at ascending doses of 25 mg, 50 mg, and 75 mg.

“While the data is still emerging, all patients treated with a single dose of NTLA-2002 in the 25 and 75 mg dose cohorts had rapid and significant reductions in plasma kallikrein levels,” added Danny Cohn, MD, senior author on the study. “For the three patients in the 25 mg dose cohort who reached a pre-determined time point where their HAE attacks were assessed, all patients had a significant reduction in HAE attacks as well.”

At both the 25 and 75 mg dose levels, NTLA-2002 was generally well tolerated, and most adverse events were mild in severity. The most frequent adverse events were infusion-related reactions, which were mostly Grade 1 and resolved within one day. There have been no dose-limiting toxicities, no serious adverse events, and no adverse events of Grade 3 or higher observed to date.

“These early data support NTLA-2002 as a potential one-time treatment to cure the symptoms of HAE,” noted Longhurst, lead author of the study. “Clinical development will continue for this program with the randomized, Phase II portion of the clinical trial to begin in the first half of 2023.”

Longhurst’s presentation was entitled, “In vivo CRISPR/Cas9 editing of KLKB1 in Patients with Hereditary Angioedema: A First-in-Human Study.”