Patients satisfied with preventive treatment: Australian study
Danazol preferred for milder HAE cases, Takhzyro for higher disease burden
Hereditary angioedema (HAE) patients in South Australia are generally satisfied with their prophylactic (preventive) treatment regimens, a study found.
Danazol appeared to be a popular choice for patients with milder disease, while newer therapies like C1 esterase inhibitor (C1-INH) products and Takhzyro (lanadelumab) were preferred for patients with a more significant disease burden.
The prevalence of HAE in the studied region was found to be of one case in every 52,400 people, consistent with other international reports.
“Our population survey indicates that current long-term prophylaxis therapies … applied to appropriate patients taking into account disease activity and drug risks and tolerance, are effective for HAE attack prevention and produce high levels of satisfaction,” the researchers wrote.
The study, “Hereditary angioedema prevalence and satisfaction with prophylaxis in South Australia,” was published in the World Allergy Organization Journal.
Evaluating prevalence, disease burden, preventive treatment
HAE types 1 and 2 are caused by mutations in the SERPING1 gene, leading to the lack or malfunction of the C1-INH protein, which is normally needed to regulate the signaling pathways that lead to the production of bradykinin. The swelling attacks that characterize HAE are caused by the overproduction of bradykinin.
HAE is a rare disease, estimated to affect between one in 30,000 to one in 92,000 people, depending on the region and study methodology used. In Australia, there have not been any studies to systematically evaluate HAE prevalence and patients’ disease burden. The researchers set out to do that, and asked adult patients complete a survey about their symptoms, life quality, and therapeutic experiences.
To ascertain the number of HAE cases, the scientists recorded known HAE patients being treated at their clinic and others in the region, in addition to screening medical and pharmacy records for codes related to HAE from January 2021 to July 2022.
Across a population of about 1.8 million in South Australia, 35 confirmed HAE cases were identified, representing a prevalence of one case in 52,400 people. The study identified eight families and seven people with no family history of the disease.
Four people identified as aboriginal or Torrens Strait Islander, reflecting a prevalence of HAE of one in 14,200 in that minority ethnic group.
Most patients — 31 people — had HAE type 1, 18 were male, and the average overall age was 37.
“Whilst there may be other cases missed, our figure represents a minimum and probably close to accurate prevalence figure, and is in line with international reports,” the researchers wrote.
Seventeen of the 31 adult patients agreed to complete questionnaires designed to assess their HAE symptoms, life quality, and perspectives on treatment.
All but one patient reported experiencing some type of diagnostic delay, with a median delay of 11.5 years after symptoms were first evident.
Eleven people were initially diagnosed with the wrong condition and were treated with a range of inappropriate medications. Three people had unnecessary appendectomies as a result of incorrect diagnoses.
Abdominal attacks were the most common symptoms reported, and airway or throat attacks were the least common. For people with a family history of disease, eight reported a family member had died from a fatal attack.
Of those surveyed, more than half (53%) were currently being treated with oral danazol, and those patients generally reported good overall life quality and low HAE disease activity.
Danazol was mostly used by men and post-menopausal women, as danazol is similar to the male sex hormone testosterone and can have side effects in younger women. Continued use of danazol was also favored by patients with milder disease who only required a low dose.
Patients with a higher disease burden and premenopausal women favored newer therapeutic options. Twelve percent of survey respondents were using C1-INH products, and 35% were using Takhzyro.
Individuals on these medications generally reported good disease control and life quality, although one patient on a C1-INH product and two on Takhzyro reported poor disease control, all of whom had relatively recently switched from other treatments.
“Overall, we conclude that disease activity in our HAE cohort is low, on par with international interventional studies, and minimally impacts productivity,” the researchers wrote.
Patients reported using a mean of 1.3 prior therapies, although seven people had only been treated with danazol. In general, treatment satisfaction improved after patients were started on most therapies. Four patients who had previously used C1-INH products reported an improvement in treatment satisfaction after switching to Takhzyro.
“Future therapies should prioritize continued reduction in the burden of treatment and further normalise quality of life in this population,” the researchers wrote.
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