CSL ANDEMBRY Phase 3b Backs Ages 2–11 HAE Filing

Key Takeaways

• Phase 3b open-label study enrolled children aged 2–11 with hereditary angioedema.
• Ages 6–11 (n=16) received 100 mg monthly; ages 2–5 (n=6) received 100 mg every two months.
• Majority remained attack-free over 12 months; safety aligned with prior studies.
• ANDEMBRY is already approved in 40+ countries for patients aged 12 and older.

ANDEMBRY pediatric Phase 3b at a glance

Field	Detail
Product	ANDEMBRY (garadacimab-gxii)
Company	CSL (ASX: CSL)
Mechanism	Monoclonal antibody targeting factor XIIa
Study	Multicenter, open-label Phase 3b in ages 2–11
Dosing	100 mg monthly (6–11; n=16); 100 mg q2mo (2–5; n=6)
Key signal	Majority attack-free over 12-month treatment
Next step	Pediatric filings planned H1 of CSL fiscal year

What did CSL announce?

CSL reported positive top-line Phase 3b results for ANDEMBRY (garadacimab-gxii) in children aged 2 to 11 years with hereditary angioedema. The multicenter open-label study showed a favorable safety and tolerability profile consistent with previous studies, and treatment response across the population, with the majority of participants remaining attack-free during 12 months of treatment.

Source: CSL's July 27 PR Newswire Phase 3b pediatric ANDEMBRY release.

How was the pediatric study dosed?

Participants aged 6 to 11 years (n = 16) received 100 mg of ANDEMBRY once monthly. Participants aged 2 to 5 years (n = 6) received 100 mg every two months. Total enrolled pediatric patients reported in the top-line were 22. Full attack-rate reductions, confidence intervals, and adverse-event grades were reserved for a future congress and journal submission.

ANDEMBRY is already approved in over 40 countries for prevention of HAE attacks in adults and adolescents aged 12 years and older. The new data are intended to support expanding that prophylaxis indication down to age 2.

Why factor XIIa inhibition matters in HAE?

Garadacimab is a monoclonal antibody that inhibits factor XIIa at the top of the bradykinin-producing cascade. CSL said the antibody was discovered and optimized at its Bio21 research site, with clinical manufacturing at the Broadmeadows Biotech Manufacturing Facility in Australia — a clear APAC R&D footprint for a globally marketed rare-disease biologic.

HAE epidemiology cited by CSL is about 1 in 10,000 to 1 in 50,000 people, driven by deficient or dysfunctional C1 esterase inhibitor. Attacks can involve the airway and be life-threatening. Broader HAE trial listings can be tracked on ClinicalTrials.gov, and Australian regulatory context via Australia's TGA.

• Ages 2–5 use every-two-month 100 mg dosing in this Phase 3b design
• Ages 6–11 use once-monthly 100 mg
• Open-label design — no placebo arm in this pediatric cohort
• Filings planned in first half of CSL's fiscal year

What should APAC rare-disease desks watch?

Watch which agencies receive the first pediatric supplements (FDA, EMA, TGA, PMDA, NMPA) and whether labels retain the age-banded dosing used in Phase 3b. Because the study is open-label and small (n=22), regulators may request additional PK bridging or post-marketing surveillance in the youngest cohort.

Competitive prophylaxis options already serve adolescents and adults; the strategic APAC angle is CSL extending an Australian-discovered FXIIa antibody into younger children rather than launching a new mechanism.

What remains unproven?

Numeric attack-rate reductions, exact attack-free percentages, and grade ≥3 adverse-event rates were not in the top-line release. Open-label pediatric data cannot estimate placebo-adjusted efficacy. Approval of the ages 2–11 indication is not guaranteed until agencies complete review.

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Frequently Asked Questions

Primary Sources

• CSL July 27 PR Newswire ANDEMBRY Phase 3b pediatric results
• ClinicalTrials.gov registry home
• Therapeutic Goods Administration (Australia)