Older patients with hereditary angioedema types 1 or 2 can as safely be treated for an acute attack with Firazyr (icatibant) as younger ones, a study found, even though people 65 or older tend to metabolize medicines differently and often are being treated for multiple disorders.
The study, “Elderly versus younger patients with hereditary angioedema type I/II: patient characteristics and safety analysis from the Icatibant Outcome Survey,” was published in the journal Clinical and Translational Allergy.
Hereditary angioedema is marked by severe and recurrent swelling, most commonly in the limbs, face, intestinal tract, and airways. The disease is mostly caused by a deficiency in the C1 inhibitor protein, either due to low protein levels (type 1) or because an abnormal protein is produced (type 2). Collectively, these patients have hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE).
While symptoms of C1-INH-HAE typically begin between in childhood (between ages 5 and 11) and worsen during puberty, C1-INH-HAE can start at any age and recur throughout life.
Firazyr, by Shire, is a subcutaneous (under the skin) injection medication shown to be both effective and safe in treating acute attacks in adults with C1-INH-HAE across several Phase 3 clinical trials. Its use was approved by the U.S. Food and Drug Administration for adults (ages 18 and older) in 2011, and by the European Medicines Agency for children through adults (older than age 2) in 2008.
However, the mean age of patients enrolled in these trials was under 65. And few studies since have evaluated its safety in older patients, although physicians are increasingly administering Firazyr to this population.
An international group of researchers set out to identify treatment-related adverse events in older people being treated with Firazyr.
The Icatibant Outcome Survey (IOS) is an ongoing international, observational registry study (NCT01034969) designed to monitor the long-term safety and effectiveness of Firazyr across sites in 13 countries.
Using the IOS database, researchers compared patient characteristics and safety findings in 100 people ages 65 and older to those of 772 younger patients.
Overall results showed that elderly patients had had their first symptoms later (age 17) than younger one (age 12), and had been diagnosed at a more advanced age — 41 years old vs. 19.4.
Delays in diagnosing older patients reached a median of 24 years, compared to five years for younger patients, but the difference was only significant for those with a family history of the condition — a 23.9-year delay vs. 3.5 years. In the absence of family history, delays were 10.2 years among elderly patients and 9.1 years for younger ones.
Older patients were also more likely to have other conditions (comorbidities) than younger ones, including high blood pressure, heart disease, stroke, bleeding disorders, gastrointestinal disorders, diabetes, and lung conditions. As a result, they also used more medications than did younger patients. This, plus age-related differences in metabolizing drugs, “underscores the importance of monitoring the safe use of medication in this population,” the researchers wrote.
Throughout the study, Firazyr was used to treat 6,798 attacks across 574 people. Ten percent of these attacks occurred in the older patient group, but the rate of attacks per patient and their severity was similar across both groups. Attack location was also similar.
Researchers did not observe any treatment-related and serious adverse events in the elderly group. Two younger patients reported three possibly Firazyr-related serious adverse events: gastritis (stomach inflammation) and acid reflux in the esophagus in one, and an angioedema (swelling) crisis in the other.
The percentage of patients with at least one possible mild or moderate treatment-related adverse event was similar in elderly (2%) and younger patients (2.7%). No deaths linked to Firazyr use were identified.
“Despite the fact that elderly patients had significantly more comorbidities and were receiving a greater number of concomitant medications, the occurrence of icatibant-related AEs [adverse events] was similar in the treated elderly versus younger population, with no significant differences noted between groups with regard to seriousness or severity of AEs,” the researchers wrote.
“Our analysis did not identify any new or unexpected safety concerns,” they concluded.