D3.443 - Patient-Reported Outcomes With Long-Term Donidalorsen Treatment Among Patients In Europe With Hereditary Angioedema: 1-Year Interim Results From The OASISplus Switch Cohort

Hereditary angioedema (HAE) is a rare disorder that negatively impacts patients’ quality of life (QoL) due to unpredictable, potentially life-threatening attacks of tissue swelling. In the Switch cohort of the OASISplus study (NCT05392114), patients switched from their prior long-term prophylactic medications (LTPs) to donidalorsen, a prekallikrein-directed antisense oligonucleotide indicated in the US for prophylaxis to prevent attacks of HAE in adult and paediatric patients ≥12 years. Here, we report interim patient-reported outcomes (PROs) from patients in Europe who switched to donidalorsen and have remained on treatment for up to 1 year. 

The Switch cohort of the ongoing OASISplus study consisted of patients ≥12 years with HAE on stable doses (≥12 weeks) of lanadelumab, C1 inhibitor (C1INH), or berotralstat who switched, without washout, to donidalorsen 80 mg subcutaneously once every 4 weeks (Q4W), per a protocol-specified switching algorithm. PROs assessed at baseline and Week 52 included Angioedema-QoL (AE-QoL), Angioedema Control Test (AECT), and Treatment Satisfaction Questionnaire for Medication version 2 (TSQM-II) assessments. 

Patients from 9 European countries were included in OASISplus, and 21 patients (lanadelumab, n = 5; C1INH, n = 9; berotralstat, n = 7) enrolled in the Switch cohort. Of these, 17 (81%) completed 1 year of treatment and remained in the study. Overall, patients reported a clinically meaningful (≥6-point) mean (SD) reduction (improvement) in AE-QoL total score of 20.8 (21.5) points from baseline to Week 52; improvements in AE-QoL total scores were reported regardless of prior LTP (lanadelumab, 20.6 [33.3]; C1INH, 15.6 [21.2]; berotralstat, 26.7 [21.1]). Among all patients with a baseline and Week 52 AECT assessment, 94% (16/17) reported well-controlled disease (AECT ≥10) after 52 weeks of donidalorsen treatment compared with 41% (7/17) at baseline. Lastly, overall mean (SD) TSQM-II global treatment satisfaction scores increased (improved) by 20.6 (18.3) points from baseline; improvements were reported from each prior LTP group (lanadelumab, 4.2 [5.9]; C1INH, 14.6 [12.4]; berotralstat, 36.7 [19.2]).

In the European OASISplus Switch cohort, patients with HAE who switched from their prior LTP to donidalorsen Q4W reported improved QoL, disease control, and treatment satisfaction at 1 year.