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FAQ: Therapy
Answers on frequently asked questions about HAE therapy. Definitions can be looked up in the glossary.
Why can certain episodes of HAE be life-threatening?
If an episode of HAE involves swelling of the mucous membranes of the larynx or tongue, this can cause narrowing of the upper respiratory tract. It is potentially life-threatening and if appropriate treatment is not administered, it is estimated that a third of these patients die from suffociation. If the mucous membranes in the larynx starts to swell, immediate medical treatment is required. It may be necessary to perform an emergency incision in the windpipe (cricothyreotomy).What treatment forms for HAE are practiced?
There are three established forms of treatment for HAE: acute treatment, long-term prophylaxis and short-term prophylaxis.When is acute treatment of HAE necessary?
The aim of acute treatment is to prevent progression of the edema and bring the symptoms to an end. This applies particularly to episodes in the larynx, which can cause death if left untreated.What options are available for acute treatment?
In some European countries, only an infusion of fresh frozen plasma can be administered for acute treatment. The frozen blood plasma used for this contains the deficient C1-INH. However, there is a risk that administration of frozen plasma will exacerbate the symptoms of an episode, as it also contains factors that promote the development of HAE.A few countries (Germany, the Netherlands, Austria, Switzerland and Hungary) have approved C1-INH concentrate, which must be infused intravenously by a doctor or in hospital. In addition C1-INH concentrate is available through special patient programmes in some of the countries in which it has no marketing authorisation.
Alternatively, antifibrinolytic agents such as tranexamic acid are also used, although they are less effective and exhibit a clear side effect profile. Androgens are not suitable for acute treatment. Likewise, drugs that are used to treat allergic angioedema, such as antihistamines, glucocorticoids or adrenaline, are ineffective for HAE.
What is the aim of long-term prophylaxis?
Long-term prophylaxis is indicated in patients whose quality of life is clearly reduced by the disease. These are usually patients in whom episodes occur more than once a month or who are at high risk of developing laryngeal edema. The aim is to reduce the frequency or the severity of HAE attacks.What treatment options does long-term prophylaxis currently include?
Long-term prophylaxis consists mainly of attenuated androgens (like danazol, stanozolol and oxandrolone), synthetically produced derivatives of the male sex hormone testosterone. These substances increase production of C1-INH in the liver through an as yet unknown mechanism. The dose must be adjusted to suit the individual patient and should be as low as possible because of the frequent adverse effects (massive irreversible weight gain, muscle cramps, headache, depression, nausea, constipation, menstrual disorders, increased hair growth and virilisation in women and girls). As the risk of side effects increases with the duration of treatment, androgens often cannot be administered as long as necessary.The use of androgens in children is problematic. Androgens must not be used during pregnancy.
Tranexamic acid is another of product used for long-term prophylaxis. The group of substances that inhibit fibrinolysis is regarded as less effective than androgens but suitable for treatment of the early phase of an attack.
When is short-term prophylaxis necessary?
Short-term prophylaxis is usually used before surgical procedures or dental treatment.Where registered, C1-INH concentrate is used for this purpose and is administered 12-24 hours before the procedure. In other European countries, treatment with high-dose androgens for five to seven days is used beforehand.
What are the side effects of drug treatment for HAE?
Possible side effects of treatment for HAE depend on the drug and dose used.For example, side effects of the androgens, which are derived from the male sex hormones, include an increase in muscle mass (increased protein synthesis), elevated cholesterol levels and an increase in the number of red blood cells. The side effects of the androgens are even more pronounced in women, as they gradually develop male characteristics, a process called virilisation: a deeper, gruffer voice, more body hair, beard growth, a masculine appearance, menstrual irregularities culminating in failure to menstruate, weight gain and mood changes.
Tranexamic acid can cause allergic reactions and promote thrombosis, which increases the risk of embolism. This is associated with an increased risk of stroke. Visual disturbances have also been seen in patients using tranexamic acid.
Exacerbation of the swelling during infusion of fresh frozen plasma for treatment of an acute episode of HAE should not be ruled out, as plasma can contain factors that promote the development of HAE symptoms.
What treatments for HAE can be expected in the future?
Current treatment of hereditary angioedema is inadequate in many countries and therefore new treatment options are under clinical development: such as DX-88 a genetically engineered (recombinant) kallikrein inhibitor and Icatibant a bradykinin receptor angatonist for subcutaneous injection as well as recombinant (Rhucin®)and plasma derived C1-INH concentrate (Cynrize®), that have to be administered intravenously.| Frequently inquired |
Author: Jerini AG
Source: HAE-Network Status: 3/08 This FAQ is frequently updated. Please send us your comments or suggestions by e-mail. |
