Most Canadian Physicians Follow Guidelines, Use New HAE Therapies, Survey Shows

Most physicians in Canada say they follow the guidelines for diagnosing and treating hereditary angioedema (HAE), and to have adopted treatments with the C1 esterase inhibitors Berinert, Cinryze, and Haegarda, as well as Firazyr (icatibant injection), according to a survey.

However, more guidelines are needed to help physicians manage HAE in pregnant women and children, the clinicians say.

The study, “Canadian Physician Survey on the Medical Management of Hereditary Angioedema,” was published in the journal Annals of Allergy, Asthma & Immunology.

Hereditary angioedema is a rare disorder caused by a deficiency in the C1 esterase inhibitor (C1-INH) protein. It is marked by recurrent and acute attacks of swelling (edema) in the deeper layers of the skin, often affecting the face, airways, and gastrointestinal system.

It is potentially life-threatening, particularly if it leads to airway swelling, which could prevent breathing.

In recent years, the U.S. Food and Drug Administration and Health Canada have approved new therapies for preventing flares or treating acute attacks.

The new drugs include Berinert and Firazyr for acute episodes, and Cinryze and Haegarda to prevent flares.

Meanwhile, several international and national guidelines were launched for the management of patients with HAE. But little is known about how physicians are managing these patients in clinical practice.

To see if Canadian doctors are following guideline recommendations and have adopted new therapies, researchers surveyed physicians who are currently taking care of HAE patients in Canada.

Researchers reached physicians with the help of the Canadian Hereditary Angioedema Network (CHAEN), the Canadian Society of Allergy and Clinical Immunology (CSACI), and the Canadian Hematology Society (CHS).

The survey answers from 34 physicians were analyzed, covering demographics, clinical practice, prevention and treatment, knowledge and confidence, and awareness and use of guidelines.

For diagnosis, nearly all physicians (91.2%) said they use levels of complement C4 to diagnose HAE.

Additionally, 88.2% use C1-INH levels, 85.3% use C1-INH function, and 64.7% use family history.

For long-term prevention, most physicians (93.5%) prescribed Cinryze or Haegarda, while Cyclomen (danazol, sold in the U.S. as Danocrine) and tranexamic acid were used less frequently.

The main reasons why physicians choose either Cinryze, Haegarda, or Cyclomen were side effects (85.3%), followed by mode of administration, gender, access to intravenous administration, and cost.

For short-term prevention, the preferred therapy was still Cinryze or Haegarda (76.5%), followed by Cyclomen and tranexamic acid.

To treat acute attacks, physicians most commonly prescribed Berinert (88.2%) and Firazyr (79.4%). Intravenous hydration and analgesics were also used in about one-third of the cases.

Overall, physicians felt confident when deciding which diagnostic tests to use or in choosing a treatment, particularly when deciding between the newer therapies Berinert, Cinryze, Haegarda, or Firazyr.

All physicians said they were aware of the guidelines for the management of HAE and nearly all said they used them in their clinical practice.

However, many revealed the need to have more guidance regarding specific HAE patient subgroups, including pregnant women and children, as well as preventative treatment.

“We learned that most physicians were using guidelines to guide their practices. The uptake of newer therapies to treat HAE is also high,” researchers wrote.

This is the first characterization of HAE medical management by Canadian physicians, which “can be used as a basis for comparison with future studies, particularly as new therapies are introduced to the Canadian market,” researchers suggest.