CSL's Andembry Wins FDA Approval as First Monthly Preventive Treatment for Hereditary Angioedema

The U.S. Food and Drug Administration (FDA) has granted approval to CSL's Andembry (garadacimab) as the first monthly Factor XIIa inhibitor for the prevention of hereditary angioedema (HAE) attacks in patients aged 12 years and older. This landmark decision marks a significant advancement in HAE management, offering patients a new option for long-term disease control with a convenient administration schedule.

Breakthrough in HAE Prevention

Andembry, a monoclonal antibody discovered and developed entirely by CSL, works by targeting and blocking activated Factor XII. This novel mechanism of action inhibits the initiation of the HAE cascade, providing sustained protection against attacks. The drug is administered via subcutaneous injection on a monthly basis, potentially improving patient compliance and quality of life.

Bill Mezzanotte, head of R&D at CSL, emphasized the drug's importance, stating, "Andembry offers people with this life-threatening condition long-term control over their disease along with a convenient administration method."

Compelling Clinical Data

The FDA's approval was supported by robust data from the pivotal Phase III VANGUARD study. Key findings include:

• 61.5% of patients remained free from HAE attacks after receiving Andembry
• An average 86.5% reduction in HAE attack rate compared to placebo

Additionally, interim results from an open-label extension study published in the journal Allergy in October 2024 demonstrated Andembry's long-term efficacy and safety:

• 93% of treated patients rated their response as "good" or "excellent" over nearly 14 months of treatment
• Treatment-related toxicities were observed in 13% of patients, with most being injection-site reactions

Market Availability and Competition

CSL has announced that Andembry will be launched immediately, with availability to patients expected "before the end of June." This swift market entry positions CSL at the forefront of HAE prevention, potentially capturing a significant share of the market.

The approval comes amid a competitive landscape in HAE treatment. KalVista Pharmaceuticals recently faced a setback when the FDA delayed its decision on sebetralstat, an oral HAE candidate, by approximately four weeks due to resource constraints. Meanwhile, Intellia Therapeutics is advancing its gene editing approach, lonvoguran ziclumeran, which has shown promising results in an ongoing Phase I/II study, demonstrating a 98% mean decrease in monthly HAE attacks.