Haegarda Safe, Effective in Older HAE Patients, Trial Analysis Shows 

Steve Bryson, PhD avatar

by Steve Bryson, PhD |

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Regular Haegarda treatment in older people with hereditary angioedema (HAE) — those ages 65 and older — was well-tolerated and effective in stopping HAE-related attacks, a post-hoc analysis of the COMPACT Phase 3 clinical trial revealed.

The therapy was found to be well-tolerated even in patients with multiple coexisting medical conditions who were taking various additional medications.

The results of the analysis were published in the journal Annals of Allergy, Asthma & Immunology, in a study titled “Long-term Safety and Efficacy of Subcutaneous C1-Inhibitor in Older Patients With Hereditary Angioedema.”

HAE can be caused by mutations in the SERPING1 gene, which can lead to a deficiency in a protein called C1-inhibitor (C1-INH). People with this condition experience sudden and recurring episodes of swelling under the skin, in the gastrointestinal tract, and in the upper airways. 

Haegarda is a C1-INH replacement medication by CSL Behring approved for the long-term preventive (prophylactic) treatment of HAE in adolescents and adults.

Its approval was based on the positive results of the COMPACT Phase 3 trial (NCT01912456), which demonstrated that Haegarda lowered the number of HAE attacks by a median of 95% at a dose of 60 IU/kg administered by under-the-skin (subcutaneous) injection twice weekly. 

An open-label extension (OLE) part of the COMPACT trial included patients who completed the placebo portion of the COMPACT trial as well as participants who had not been treated with Haegarda (treatment-naive). All were randomly assigned to receive Haegarda at either 40 IU/kg or 60 IU/kg twice weekly for 52 weeks. Those in the U.S. had the option to continue treatment for up to 140 weeks.

The median annual attack rate for those receiving 40 IU/kg was 1.3, and the need for rescue medicine was a median of 0.2 per year, the results showed. For those taking 60 IU/kg, the median attack rate was 1.0 per year; none of these patients required rescue medicine.

Despite this success, treating HAE in people older than 65 presents several challenges. These include age-related physiological changes that may affect Haegarda’s safety profile, and coexisting medical conditions (comorbidities) likely treated with additional medications (polypharmacy). 

Thus, scientists at CSL Behring, in collaboration with researchers at various sites across the U.S., Canada, and Europe, evaluated the safety and efficacy of Haegarda in a subgroup of patients, ages 65 and older, who were part of the OLE study of the COMPACT trial. 

Of the 126 participants enrolled in the OLE study, 10 patients between the ages of 65 and 72 were analyzed.

All 10 patients had one or more coexisting medical conditions, and eight had multiple medical conditions, including hypertension, diabetes, high levels of fat in the blood, and anxiety or depression. 

As a result of multiple co-conditions, these older patients were prescribed multiple non-HAE-related medications. Among the participants, six were taking more than five medicines during the study period.

All of the patients were overweight (body mass index, BMI, of 25 kg/m2 or higher), and seven were obese (BMI of 30 kg/m2 or higher).

Efficacy data regarding therapeutic responses for Haegarda were available for nine of the patients, and of these, six responded to the therapy. Compared to before the study, HAE attacks in these responders were reduced by 50% or more. Three of these patients were attack-free.

“The three attack-free patients were taking the higher 60 IU/kg dose of Haegarda and had preventative levels of the medicine in their blood,” the researchers wrote.

Among the three non-responders, two did not have a decrease in attacks and one experienced a 42% reduction. These three patients had multiple co-conditions and were taking several medications.

Haegarda was found to be well-tolerated by the participants, with local injection-site reactions being the most common adverse effect reported. Serious adverse effects were reported in two patients, with one experiencing low potassium levels (hypokalemia) and dehydration, and the other having pneumonia and an HAE attack that led to hospitalization. Both events resolved and did not lead to treatment discontinuation.

“In conclusion, the results of this post-hoc analysis of the OLE of the COMPACT trial demonstrated that [Haegarda] provides effective, safe, and well-tolerated long-term prophylaxis of angioedema attacks in patients ≥65 years old with [hereditary HAE] in spite of multiple comorbidities and polypharmacy,” the researchers wrote. 

According to the team, additional analyses using a broader definition of older adults — namely, those over 60 or those 55 and older — are planned.