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WHY HAE REQUIRES LIFELONG
MANAGEMENT

Image composed of HAE treatment items and text bubbles and sticky notes that say, "New year—time to renew authorizations," "Why is this so hard? Getting my meds shouldn't be a constant struggle," "I need a letter of medical necessity for travel," and "I’m in pain. I need help."

HAE Is a Genetic Condition

While there is no cure for HAE, treatments help manage the condition.

A diagram illustrating the kallikrein-kinin system, a pathway that regulates swelling. It shows how the KLKB1 gene produces plasma prekallikrein, which ultimately leads to bradykinin production. C1-INH controls the kallikrein-kinin system, and C1-INH dysregulation causes the overproduction of bradykinin, which leads to HAE attacks.

Overproduction of bradykinin leads to swelling attacks, which can occur via multiple pathways in patients with Type I and Type II hereditary angioedema (HAE). A key pathway is the kallikrein-kinin system.1-5

The Kallikrein-Kinin Pathway

The kallikrein-kinin system ultimately produces bradykinin. This process is initiated when Factor XII activates to Factor XIIa. This converts plasma prekallikrein, which is made according to instructions from the KLKB1 gene, to kallikrein. Kallikrein then cleaves high-molecular-weight kininogen (HMWK) to release bradykinin. Bradykinin increases vascular permeability, promotes vasodilation, and activates sensory nerves. In people without HAE, the pathway is tightly regulated by C1 esterase inhibitor (C1-INH).1-5

C1-INH Dysregulation and HAE

Type I and Type II HAE are caused by mutations in the SERPING1 gene, leading to dysfunctional or low levels of C1-INH. This results in uncontrolled feedback activation of Factor XIIa and kallikrein, and subsequently overproduction of bradykinin, causing blood vessels to leak into surrounding tissues in painful HAE swelling attacks.5-7

Approved treatments MAY require repeated lifelong dosing to manage attacks.5-7

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References:

  1. Bork K, Hardt J, Witzke G. Fatal laryngeal attacks and mortality in hereditary angioedema due to C1-INH deficiency. J Allergy Clin Immunol. 2012;130(3):692-697. doi:10.1016/j.jaci.2012.05.055
  2. Farkas H. Pediatric hereditary angioedema due to C1-inhibitor deficiency. All Asth Clin Immun. 2010;6(1):18. doi:10.1186/1710-1492-6-18
  3. Mendivil J, Murphy R, De La Cruz M, et al. Clinical characteristics and burden of illness in patients with hereditary angioedema: findings from a multinational patient survey. Orphanet J Rare Dis. 2021;16(1):94. doi:10.1186/s13023-021-01717-4
  4. Banerji A, Li Y, Busse P, et al. Hereditary angioedema from the patient’s perspective: A follow-up patient survey. Allergy Asthma Proc. 2018;39(3):212-223. doi:10.2500/aap.2018.39.4123
  5. De Maat S, Hofman ZLM, Maas C. Hereditary angioedema: the plasma contact system out of control. 
J Thromb Haemost. 2018;16(9):1674-1685. doi:10.1111/jth.14209
  6. Maurer M, Magerl M, Betschel S, et al. The international WAO/EAACI guideline for the management of hereditary angioedema-the 2021 revision and update. Allergy. 2022;77(7):1961-1990. doi:10.1111/all.15214
  7. Wedner HJ. Hereditary angioedema: Pathophysiology (HAE type I, HAE type II, and HAE nC1-INH). Allergy Asthma Proc. 2020;41(Suppl 1):S14-S17. doi:10.2500/aap.2020.41.200081