D3.442 - Patient-Reported Outcomes With Long-Term Donidalorsen Treatment Among Patients In Europe With Hereditary Angioedema: 1-Year Interim Results From The OASISplus Open-Label Extension Cohort

Hereditary angioedema (HAE) is a rare disorder characterised by potentially life-threatening attacks of tissue swelling that negatively impact patients’ quality of life (QoL). In the phase 3 OASIS-HAE study (NCT05139810), treatment with donidalorsen, a prekallikrein-directed antisense oligonucleotide approved in the US for prophylaxis to prevent attacks of HAE in adult and paediatric patients ≥12 years, significantly improved QoL versus placebo in patients with HAE. Here, we report interim patient-reported outcomes (PROs) from European patients in the ongoing open-label extension (OLE) cohort of the OASISplus study (NCT05392114).

The OLE cohort included European patients ≥12 years with HAE who rolled over from the phase 3 OASIS-HAE trial. Patients received donidalorsen 80 mg subcutaneously once every 4 weeks (Q4W) or 8 weeks (Q8W) for up to 156 weeks. This interim analysis evaluated Angioedema QoL (AE-QoL), and Angioedema Control Test (AECT) PROs evaluated at baseline in the OASIS-HAE study and at Week 52 of the OASISplus OLE. Treatment Satisfaction Questionnaire for Medication version 2 (TSQM-II) was also assessed at Week 52 of the OLE.

Patients from 9 European countries were included in OASISplus, and 43 (Q4W, n = 34; Q8W, n = 9) enrolled in the OLE cohort. Of these, 40 (93%) completed 1 year of treatment and remained in the study. Overall, patients reported a mean (SD) reduction (improvement) in AE-QoL total score of 28.5 (16.3) points from baseline in the OASIS-HAE study to Week 52 of the OLE, surpassing the minimal clinically important difference (MCID) of 6 points. The AE-QoL MCID was also exceeded in both treatment groups: Q4W, 30.6 (15.7) points; Q8W, 21.9 (17.4) points. Improvements were reported across all 4 AE-QoL domains (fatigue/mood, fears/shame, functioning, and nutrition) in both Q4W and Q8W groups. All 35 (100%) patients with an AECT score at baseline and Week 52 reported well-controlled disease (AECT ≥10) at Week 52 compared with 9 (25.7%) patients at baseline. At Week 52, TSQM-II mean (SD) global satisfaction scores were 92.8 (9.9) overall (Q4W, 93.8 [8.7]; Q8W, 89.8 [13.0]; maximum [best] score, 100).

In the OASISplus OLE cohort, patients in Europe with HAE reported improved QoL, disease control, and high treatment satisfaction scores with donidalorsen treatment over 52 weeks.