Initial rates of common treatment-emergent adverse events from baricitinib 2 mg appear to remain stable or decrease with prolonged exposure.
A new study lends support to the established clinical safety profile of 2 mg baricitinib in adult patients with atopic dermatitis.
To date, 6 double-blind, randomized, placebo-controlled studies—as well as 2 long-term extension studies—have been conducted to evaluate the safety and efficacy of the selective Janise kinase (JAK) 1 and 2 inhibitor as either a monotherapy or combination therapy.
Led by Brett King, MD, PhD, Department of Dermatology, Yale School of Medicine, an investigative team performed an integrated analysis of all 8 studies to further evaluate the baricitinib’s safety through 2.4 years of follow-up.
Their analysis included 2 datasets—one that compared baricitinib with placebo during the 16-week period in the trials, and another that reported on estimated incident rates (IRs) of adverse events in all those who received baricitinib at any time.
As such, across all clinical trials, 1598 patients received once-daily baricitinib 2 mg for 1434.2 patient-years of exposure. Furthermore, 45.6% were treated for ≥1 year, and 2.1% were treated for ≥2 years.
Compared with placebo, a higher proportion of patients experienced ≥1 treatment-emergent adverse events (57.9% vs 51.6%).
In both treatment groups, most of the events were considered mild (baricitinib 2 mg, 32.8%; placebo, 29.9%) or moderate (baricitinib 2 mg, 22.2%; placebo, 18.3%) in severity.
Even more, the placebo group saw a higher frequency of serious adverse events (2.7%, IR = 9.2) compared with the baricitinib group (1.6%, IR = 5.2).
In the placebo-controlled dataset, the most frequently reported treatment-emergent adverse events were nasopharyngitis, headache, upper respiratory tract infection, nausea, diarrhea, and herpes simplex.
As for the baricitinib-only dataset, serious adverse events were those in the Medical Dictionary for Regulatory Activities (MedDRA) system organ classes Skin and subcutaneous tissue disorders and Infections and infestations.
The investigators also reported that a similar proportion of patients in both groups discontinued the study drug due to adverse events.
Among all patients who received baricitinib, “the most common MedDRA system organ class for permanent discontinuation was Skin and subcutaneous disorders (21.4%) with 50% of these events reported as worsening of dermatitis atopic.”
The most common MedDRA system organ class leading to temporary interruptions was Infectious and infestations (61%).
However, serious infections and opportunistic infections were found to be low in frequency and similar between treatment arms. Herpes simplex was notably higher for baricitinib 2 mg (3.8%) than for placebo (2.8%), but rates decreased with extended exposure to the JAK inhibitor.
There were no reported malignancies, gastrointestinal perforations, or major adverse cardiovascular events for baricitinib in the placebo-controlled period.
In the baricitinib-only dataset, 5 malignancies were reported, as well as 2 major adverse cardiovascular events, 1 peripheral venous thrombosis, and 1 arterial thrombosis. There were no pulmonary embolisms, deep vein thromboses, or deaths.
Therefore, the investigators concluded the safety analysis was notably consistent with the already established safety profile of bariticitinib 2 mg, a recommended started dose for those with moderate-to-severe atopic dermatitis.
“The observed patterns and rates of common treatment-emergent adverse events were similar or numerically lower with prolonged exposure to baricitinib 2 mg,” they added.
Although there were few cases of major adverse cardiovascular events and other malignancies linked with baracitinib, the investigators acknowledged their longer latency period.. Therefore, a longer treatment duration can help further elucidate the true risks for these adverse events.
“Atopic dermatitis is a chronic disease and additional long-term data will be essential to further understand other potential risks with extended baricitinib 2 mg exposure,” King and team concluded.
The study, “Extended Safety Analysis of Baricitinib 2 mg in Adult Patients with Atopic Dermatitis: An Integrated Analysis from Eight Randomized Clinical Trials,” was published online in American Journal of Clinical Dermatology.