Long-term prevention of hereditary angioedema attacks with lanadelumab in adolescents.

Background: Lanadelumab was well tolerated and effective in preventing hereditary angioedema (HAE) attacks in the phase 3, double-blind, placebo-controlled Hereditary angioEdema Long-term Prophylaxis (HELP) study and subsequent HELP open-label extension (OLE) study (NCT02741596).

Objective: To evaluate outcomes from HELP OLE for adolescent patients aged 12 to 17 years.

Methods: The HELP OLE study comprised patients who completed the HELP study (rollovers) and new eligible (lanadelumab-naive) patients. Rollovers received a single dose of lanadelumab 300 mg at the last HELP study visit (day 0). Treatment was then paused until patients experienced their first investigator-confirmed HAE attack, after which lanadelumab 300 mg was administered every 2 weeks for up to 33 months (4 wk/mo). Lanadelumab-naive patients received lanadelumab 300 mg every 2 weeks from day 0. Patient-reported outcomes included Angioedema Quality of Life Questionnaire. Safety was monitored throughout the study.

Results: The subgroup analysis included 21 patients (8 rollovers and 13 lanadelumab-naive patients); 95.2% completed at least 30 months in the study. The mean (SD) monthly attack rate decreased from 1.58 (1.0) at baseline to 0.11 (0.2) during treatment (mean, 94.7% reduction). A total of 8 (38.1%) patients were attack-free during treatment and, on average, 99.1% of days were attack-free (mean, 27.7 d/mo). Patients reported a mean (SD) Angioedema Quality of Life Questionnaire total score of 27.5 (17.5) at baseline vs 7.5 (13.2) at the end of the study. There were 12 (57.1%) patients who reported treatment-related treatment-emergent adverse events; however, there were no treatment-related serious adverse events.

Conclusion: Lanadelumab provided long-term efficacy in preventing HAE attacks, was associated with clinically meaningful improvements in health-related quality of life and high levels of treatment satisfaction, and was well tolerated in adolescent patients.

Trial Registration: ClinicalTrials.gov Identifier: NCT02741596.