SAN FRANCISCO — More than half of patients being treated with omalizumab (Xolair) for chronic idiopathic urticaria (CIU) relapsed after the biologic therapy was discontinued, according to the first large analysis of prescribing practices and patient outcomes in the real-world setting.
Researchers reported on the experience of a nationwide allergy network with roughly 170 practitioners following omalizumab’s approval by the FDA for the treatment of chronic hives early in 2014 in a late-breaking abstract session at the American Academy of Allergy, Asthma & Immunology (AAAAI) annual meeting.
The majority of patients with CIU treated with omalizumab after approval were initiated on a 300 mg dose and were treated continuously without titration up or down for more than a year, on average.
But close to 60% of patients decreased the frequency of omalizumab administration during continuous use, suggesting that weaning patients off the drug was a common strategy, Brian D. Stone, MD, of Allergy Partners of San Diego, told MedPage Today.
He added that among the 38% patients who stopped the therapy, 55% relapsed and were back on the treatment within 5 to 10 months.
“A question that remains unanswered in real-world practice is, ‘How long should patients be treated before they are taken off therapy?,'” Stone said, adding that the vast majority of omalizumab-treated CIU patients were on the biologic for 6 months and most were on it for at least a year.
“I think this highlights the need for research to help us identify patients who are likely to relapse when taken off therapy,” he added. “In terms of counseling patients and shared decision-making, I think it is important to tell patients who are doing well on the medication that they have about a 55% chance of relapsing if they choose to stop.”
Omalizumab is approved as a once-monthly injection for patients, ages ≥12 years, whose chronic hives are not controlled by H1 antihistamines.
In clinical trials, approximately two-thirds to three-fourths of treated patients improved within 12 weeks, and approximately one-third had complete resolution (no urticaria visible and no itching) at 12 weeks on 300 mg per month.
But the trial data did not address the long-term safety and potential benefits of long-term use, or the optimal duration of treatment. The phase IV XTEND-CIU trial was designed to address these questions, and found that patients continued to benefit from treatment throughout the 48-week trial.
The percentage of patients experiencing clinical worsening during the 12 weeks after withdrawing treatment was identical in patients treated for 24 weeks before withdrawal, and those treated for 48 weeks before withdrawal, “suggesting the need to treat beyond 48 weeks.”
The real-world analysis presented at AAAAI 2019 included 1,096 patients (mean age 44.1; 74.7% female) treated by practitioners in the network Allergy Partners following omalizumab’s approval for the CIU indication.
The mean number of omalizumab administrations was 15 (median 12) and the majority of patients (983 or 89.7%) initiated omalizumab on the 300-mg dose. Just 58 patients (5.3%) initiated on the smaller approved dose of 150 mg.
Frequency of administration and dose change were assessed in 1,072 patients with two or more omalizumab administrations.
The analysis of this group revealed that the mean continuous treatment duration was 14.2 months (median 11.7 months).
A total of 872 (79.6%), 695 (63.4%), and 538 (49.1%) patients received omalizumab continuously up to 6, 9, and 12 months, respectively. Among patients who discontinued omalizumab (38.5%), 55.5% re-started it after a mean of 157.4 days (median 91 days).
The research was funded by Novartis Pharmaceuticals. One co-author is a company employee.
Stone disclosed relevant relationships with Novartis, Genentech, Sanofi, AstraZeneca, and ALK.