Hereditary Angioedema Treatments and Common Side Effects, Explained

Not long ago, being diagnosed with hereditary angioedema (HAE) meant going on the same one or two medications everyone else did. The side effects could be unpleasant, and their safety was ... well, a bit iffy.

Luckily, our understanding of this rare genetic disorder has grown by leaps and bounds.

“Treatment is about weighing pros and cons now because we’ve developed more drugs to manage the condition and HAE attacks,” says immunologist Jennifer Ohtola, MD, PhD.

Dr. Ohtola introduces us to some of the medication options and their most common side effects.

Possible side effects of HAE treatments

Most people with HAE are on two types of medications:

1. Prophylactic therapy: Taken regularly to prevent HAE attacks
2. On-demand treatment: Used during an HAE attack to stop swelling

There’s no one-size-fits-all medication for HAE. Your needs can also change, so what works for you now may not be the best choice next year.

But the research on HAE is moving quickly.

“We’re making a lot of advancements in this condition, and new medicines are coming out or actively being investigated,” Dr. Ohtola says. “That’s another reason it’s important to see your HAE specialist regularly.”

Here are some of the treatments that are currently available.

C1-inhibitors

Having HAE means that you either don’t make enough of a protein called a C1-inhibitor, or the C1-inhibitor you do make doesn’t work properly.

C1-inhibitor drugs replace that missing or faulty protein to help control swelling.

Some C1-inhibitors are used to prevent HAE attacks. Others are taken during an attack. In some cases, the same medication can be used for both.

For a long time, you had to inject C1-inhibitors directly into your vein (IV injection). Today, one of these drugs can be injected under the skin (subcutaneously) instead.

Here’s the basic breakdown:

• Berinert®: An on-demand IV injection
• Cinryze®: A prophylactic IV injection
• Haegarda®: A prophylactic, subcutaneous injection
• Ruconest®: An on-demand IV injection

Dr. Ohtola says that, in the short term, the most common side effects of C1-inhibitors are usually mild. Examples include:

• Redness at the injection site
• Headaches
• Gastrointestinal (GI) issues
• Infections

Most C1-inhibitors are created using human plasma, which raises the risk of infection. The only one that doesn’t use human blood products is Ruconest. But it isn’t as common or widely available.

Kallikrein inhibitors

Kallikrein is an enzyme that creates bradykinin, the peptide that causes swelling during an HAE attack. Kallikrein inhibitors block that enzyme to help prevent or stop attacks.

There are five kallikrein inhibitors currently available:

• Lanadelumab (Takhzyro®): A prophylactic, subcutaneous injection
• Ecallantide (Kalbitor®): An on-demand, subcutaneous injection
• Berotralstat (Orladeyo®): A prophylactic medicine you take by mouth
• Sebetralstat (Ekterly®): An on-demand medication you take by mouth
• Donidalorsen (Dawnzera®): A prophylactic, subcutaneous injection you give yourself once a month or every other month

“The side effects of kallikrein inhibitors that we know about right now are similar to C1-inhibitors — mostly headaches, injection site redness, GI upset, headaches and infections,” Dr. Ohtola notes.

Monoclonal antibodies

Garadacimab (Andembry®) is a new class of drug for treating HAE. It’s a monoclonal antibody that you inject subcutaneously once a month to prevent HAE attacks.

Monoclonal antibodies are lab-made proteins that mimic immune cells that can recognize and attack specific targets, like germs. Instead of attacking a germ, Garadacimab blocks a protein (factor XII) that triggers swelling during an HAE attack.

Common side effects are usually mild, like injection site reactions, headache, nausea and fatigue.

Attenuated androgens

Attenuated androgens were once common in HAE treatment — but now, they’re rarely used because of their side effects. Androgens are steroid hormones, like testosterone, that can help prevent HAE attacks by boosting the production of C1-inhibitors in your liver.

Attenuated androgen therapy has lots of unpleasant side effects, including:

• Acne
• Hair growth
• Weight gain
• High cholesterol
• High blood pressure
• Male characteristics in women

“It’s very uncommon for us to use these therapies anymore, and they’re not recommended for use in children and pregnant women,” Dr. Ohtola stresses.

How to manage side effects

Now that there are lots of different HAE treatment options — and still more in development — side effects aren’t something you have to just muddle through.

“If you’re having side effects or your medication isn’t working well, talk to your provider,” Dr. Ohtola urges. The more you tell your specialist about how you’re feeling and how you’re using the medicine, the better they’ll be able to adapt your treatment plan to fit your changing needs.

That may mean:

• Taking medicine to manage your side effects
• Changing the dosing, frequency or administration method of the meds you’re on now
• Switching to another medication

Having to switch or stop a drug can be discouraging. But it doesn’t mean you “failed” your treatment or that you can never try it again. It just means your needs have changed, and it may be time for a new approach.

Talk to your doctor

Side effects are just one piece of the treatment puzzle. When choosing the right HAE medication, you and your provider will also consider:

• How old you are
• How often you have attacks and your most common triggers
• Whether the medicine is available and covered by your health insurance
• How easy the drug is to self-administer
• Whether you’re interested in joining a clinical trial for a new treatment
• Other medications you take and chronic health issues you’re managing

These answers can and do change. And it’s common to use different medications in different chapters of your life. That’s why it’s important to work with an immunologist you trust.

If you’re experiencing side effects of HAE treatment, talk to your doctor. They can walk you through all the available options, and help you find the safest, easiest path forward.