Lanadelumab in Patients 2 to Less Than 12 Years Old With Hereditary Angioedema: Results From the Phase 3 SPRING Study

Background: Symptoms of hereditary angioedema (HAE) often first occur during childhood, and HAE attacks in children can be severe and substantially affect health-related quality of life (HRQoL). However, there are no approved long-term prophylaxis treatments for children aged less than 6 years. Objective: The SPRING Study (NCT04070326) evaluated the safety, pharmacokinetics, and efficacy of lanadelumab and HRQoL in patients aged 2 to less than 12 years. Methods: Over 52 weeks of treatment, patients aged 2 to less than 6 years received lanadelumab 150 mg every 4 weeks (Q4W) and patients aged 6 to less than 12 years received 150 mg every 2 weeks (Q2W) but could switch to Q4W if they were attack-free for 26 weeks. Results: We enrolled 21 patients (aged 2 to less than 6 years: n = 4; aged 6 to less than 12 years: n = 17), 20 of whom completed the study. There were no reported serious treatment-emergent adverse events or discontinuations resulting from such events. Treatment-emergent adverse events were reported for 17 patients (81.0%). The most common TEAE was injection site pain. Overall systemic exposure was comparable for both age groups. The mean (SD) attack rate during treatment decreased by 94.8% from baseline (1.84 [1.53] to 0.08 [0.17] attacks/mo), and 16 (76.2%) patients were attack-free. The attack rate reduction in both age groups was similar during the first 26-week fixed-dosing treatment. Seven patients switched from Q2W to Q4W and remained attack-free. A large, clinically meaningful increase in the Pediatric Quality of Life Inventory Generic Core Scale Total Score and a large increase in the Pediatric Quality of Life Inventory Generic Core Scale–Family Impact Module Total Score from baseline to end of study (better HRQoL) were observed. Conclusions: Findings support safety, efficacy, and improved HRQoL with lanadelumab 150 mg Q2W and Q4W regimens for the prevention of HAE attacks in patients aged 2 to less than 12 years.