Long adolescent follow-up in rare disease
Twenty of 21 participants remained in the study for at least 30 months, providing unusually long age-specific exposure information for a rare disorder.
↳ Results, Study Population
Abstract
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.
Key Claims
Primary findingTentative
Treatment with lanadelumab reduced the total mean (SD) HAE attack rate from 1.58 (1.0) at baseline to 0.11 (0.2) at EoS.
Fragile — the claim's weakest requirement is that the effect exists at all. Experimental. Every point below is traceable to a quoted passage, but this forecast has not yet been validated against known replication outcomes.
uncontrolled pre/post comparison with mixed baseline sources cannot independently identify the treatment effect
Results, Efficacy; Figure 1
SecondarySupported
A total of 8 (38.1%) patients were attack-free during treatment and, on average, 99.1% of days were attack-free.
directly reported descriptive outcomes, though derived from a small single-arm cohort
Abstract, Results; Results, Efficacy; Table 2
SecondaryTentative
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.
open-label self-report using an instrument not validated for adolescents
Abstract, Results; Results, Patient-Reported Outcomes; Figure 2
SecondarySupported
Lanadelumab 300 mg given subcutaneously Q2W was well tolerated.
long exposure with no treatment-related serious events or adverse-event discontinuations, but only 21 participants
Discussion, safety paragraph; Table 3
Derived from the full evaluation — not a separate score.
Strengths · Limitations
Strengths
Transparent efficacy and safety reporting
Attack rates, attack-free periods, adverse events, and treatment-related events are reported with denominators and cohort breakdowns in Figures 1–2 and Tables 2–3.
↳ Results, Efficacy and Safety; Figures 1–2; Tables 2–3
Relevant positioning against pediatric evidence
The Discussion compares the subgroup with the overall HELP OLE cohort and adolescent cohorts from COMPACT and APeX-S, clarifying where the analysis sits in the clinical evidence base.
↳ Discussion, paragraphs 1–3
Limitations
Uncontrolled comparison limits efficacy inference
The central 94.7% reduction comes from a single-arm pre/post analysis without a concurrent comparator or formal hypothesis testing, leaving regression to the mean and time-related effects unresolved.
↳ Methods, Study Design and Statistical Analyses; Results, Efficacy
Mixed baselines and follow-up create bias
Rollover baselines came from the HELP run-in period, whereas naive-patient baselines were historical and potentially underestimated; rollover treatment timing also produced unequal follow-up.
↳ Methods, Study Population and Study Assessments; Discussion, limitations paragraph
Adolescent PRO validity remains uncertain
The HRQoL instruments were designed and validated for adults, not participants younger than 18, yet they support the conclusion of clinically meaningful improvement.
↳ Methods, Study Assessments; Results, Patient-Reported Outcomes; Discussion, limitations paragraph
Nabu Commentary
The adolescent subgroup offers long follow-up and clearly reported descriptive efficacy, safety, and quality-of-life outcomes. Its contribution remains incremental because it is drawn from the previously published HELP OLE cohort and closely mirrors the larger cohort's results. Methodological confidence is limited by the absence of a concurrent comparator, mixed baseline definitions, and acknowledged selection effects. The Discussion identifies these constraints and compares relevant pediatric studies, but its final efficacy and HRQoL language does not fully reflect the resulting uncertainty.
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Author Note / Field Feedback
Nabu’s assessment, alongside the field’s view.
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Dimension breakdown
Study Quality
Limited2.8
Confidence mediumContribution
3.1
The analysis supplies long-term, adolescent-specific outcomes in a rare disease population with limited age-stratified evidence. Its advance is incremental because the 21 participants belong to the previously reported HELP OLE cohort and the findings are broadly comparable with that larger analysis.
Introduction, final paragraph; Discussion, paragraphs 1–3
These findings are broadly comparable with efficacy data for the overall HELP OLE treatment cohort
Methodological Rigour
2.5
Long exposure, investigator-confirmed attacks, transparent denominators, and descriptive analyses support the observational reporting. The uncontrolled pre/post comparison, mixed baseline definitions, differential rollover follow-up, and unvalidated adolescent PRO measures materially limit inference.
Methods, Study Design, Study Population, Study Assessments, and Statistical Analyses; Discussion, limitations paragraph
No formal hypothesis testing was performed.
Reporting
3.5
The article follows a clear sequence from design through efficacy, safety, and PRO results, with outcomes traceable to Figures 1–3 and Tables 1–3. The phrases “provided long-term efficacy” and “reduced” are stronger than ideal for an uncontrolled subgroup but do not obscure the reported design.
Abstract; Results; Tables 1–3; Figures 1–3; Discussion, final paragraph
Lanadelumab provided long-term efficacy in preventing HAE attacks
Positioning
2.9
The Discussion compares the findings with the overall HELP OLE cohort and adolescent evidence from COMPACT and APeX-S, and it identifies several relevant limitations. Those limitations are not fully traced through to the certainty of the attack-rate and HRQoL conclusions.
Discussion, paragraphs 1–3 and limitations paragraph
Owing to the open-label study design, patients were aware that they were receiving active treatment
Reliability
Caveats4 of 4 checks
Internal CoherenceNoted
Reported values are internally consistent, but the strength of the efficacy and quality-of-life conclusions exceeds the certainty available from an uncontrolled subgroup analysis. No numerical impossibility or methods–results contradiction was identified.
Research ConductNoted
Ethics, consent, registration, funding, and conflicts are disclosed. Confidence is nevertheless tempered by sponsor employment, stock ownership, funded medical writing, and reliance on a sponsor-controlled trial dataset.
Flags: 3 declared / 5 total
Reference IntegrityClean
38 of 38 checkable references verified
41 references in manuscript 3 are books, websites or datasets — counted, but not index-checkable
Post-Publication RecordClean
No retraction notice found in Retraction Watch.
Last checked: 18 Sep 2026
Sources: Retraction Watch ✓
Readiness
Where this paper’s evidence sits on the path from initial observation to real-world use.
Validated
Lanadelumab is already approved and recommended as a first-line prophylactic option, placing the findings close to operational use. This analysis refines population-specific confidence rather than establishing a new deployment pathway.
Introduction, lanadelumab approval and guideline paragraphs
Lanadelumab is recommended as a first-line treatment option for LTP.
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