Ionis presents positive 2-year results from the Phase 2 open label extension study of donidalorsen

Ionis presents positive two-year results from the Phase 2 open label extension study of donidalorsen in patients with hereditary angioedema

Ionis Pharmaceuticals Inc today announced positive results from an ongoing Phase 2 open-label extension (OLE) study evaluating the safety and efficacy of its investigational prophylactic medicine, donidalorsen, in patients with hereditary angioedema (HAE).

Over the two years, patients treated with donidalorsen via subcutaneous injection showed an overall sustained mean reduction in HAE attack rates of 96% from baseline, from 2.70 to 0.06 attacks per month, across all dosing groups. Furthermore, all patients treated with donidalorsen reported a clinically meaningful improvement in quality of life as measured by the Angioedema Quality of Life Questionnaire (AE-QoL) over two years. Treatment with donidalorsen was well tolerated in the studies, and there were no serious adverse events.

The study was presented at the recent American College of Allergy, Asthma & Immunology (ACAAI) Annual Scientific Meeting in November 2023.

Richard S. Geary, Ph.D., executive vice president and chief development officer at Ionis, said: “Hereditary angioedema is a significant healthcare challenge for which there is an ongoing need for long-term, sustained prophylactic treatment offering patients significant efficacy and tolerability that is easy to use. We are very encouraged by the demonstrated safety, efficacy, and quality of life profile of donidalorsen. The two-year OLE results further support donidalorsen as a potentially compelling prophylactic treatment option for patients with hereditary angioedema. We look forward to reporting pivotal topline Phase 3 results in the first half of next year.”

In a subset analysis also presented at the ACAAI Annual Scientific Meeting, 62.5% of patients receiving donidalorsen 80 mg every eight weeks remained attack-free over the two-year period and had a sustained mean reduction in HAE attack rates of 83% from baseline.

Injection site (IS) discoloration and IS reaction were the only study drug-related treatment-emergent adverse events (TEAEs) reported in more than one patient (n=2, 11.8% each). No serious adverse events were reported in the OLE study, and no TEAEs led to study discontinuation.

(Source: Ionis)