Approved HAE Treatments
Five products are currently approved and registered by the FDA (the United States Food and Drug Administration), the EMA (the European Medicines Agency) and a number of other countries to treat HAE:
As might be expected from its different pathogenesis, angioedema seen in HAE does not respond to the drugs employed in treating other forms of urticaria/angioedema such as antihistamines, epinephrine, and corticosteroids. While epinephrine, in particular, may have a transient effect on swelling, it does not alter the course of an attack.
Maintaining airway patency is the primary concern for patients with laryngeal edema. If the airway is threatened, the patient should be intubated by an experienced physician. In addition, the capability for emergency tracheostomy should be readily available. Because gastrointestinal edema usually involves excruciating pain, frequent vomiting, and the potential for hypotension, therapy should include aggressive fluid replacement and pain management.
In the past, some physicians have used fresh frozen plasma in the acute attack setting, but this therapy is considered controversial because in addition to C1-inhibitor, fresh frozen plasma contains substrates of the complement and kinin systems that could produce a vasoactive peptide and cause an attack exacerbation.
Treating Children with HAE
Fortunately, most prepubescent children with HAE do not suffer from frequent attacks and infrequent flares affecting the abdomen can be managed by using pain relievers and anti nausea agents. The small number of severely affected children who experience frequent and severe attacks must be managed on a case by case basis. Every physician will need to discern for him or herself how the approved medications may prove most useful for treating their young patients.
New Treatments on the Horizon
New HAE medicines are still being developed:
- A bradykinin antagonist receptor (Firazyr) is being evaluated for the treatment of acute attacks in children with HAE.
- A new phase III registration trial is open to patients with frequent attacks of HAE. The aim of this study is to assess the efficacy of C1-esterase inhibitor in preventing HAE attacks when it is administered under the skin (subcutaneously) of patients with HAE. The study will measure the number of HAE attacks that patients experience while receiving C1-INH versus placebo subcutaneously. All patients will be able to take on-demand medication for acute attacks at any time during the study. The study is sponsored by CSL Behring. Further information about the trial can be found here: http://clinicaltrials.gov/show/NCT01912456
- An oral kallikrein inhibitor is being evaluated as a prophylactic treatment in adults with HAE. The purpose of the study is to assess whether treatment with the study drug reduces the frequency of attacks compared to placebo. Each patient will participate in a 12-week dosing period and will be asked to come to the research clinic 6 times over a 4- 6 month period. Patients will record their HAE attacks and study drug dosing in an electronic diary daily. Patients should have access to and take their on-demand treatment for acute attacks at any time as needed during the study. Additional information about the study can be found at http://clinicaltrials.gov/ct2/show/NCT02303626?term=bcx4161&rank=3
- Dyax Corp. has reported positive safety, pharmacokinetic, biomarker, and efficacy results from the Phase 1b clinical study of their investigational product, DX-2930. Discovered by Dyax, DX-2930 is a fully human monoclonal antibody inhibitor of plasma kallikrein being developed for the prevention of HAE attacks.