HealthDay News — The most common adverse event in participants with early Alzheimer disease receiving high-dose aducanumab in the two phase 3 randomized clinical trials was amyloid-related imaging abnormalities-edema (ARIA-E), which occurred in 35.2 percent of participants, according to research published online Nov. 22 in JAMA Neurology.
Stephen Salloway, M.D., from Brown University in Providence, Rhode Island, and colleagues describe the radiographic and clinical characteristics of ARIA that occurred in two phase 3 randomized clinical trials (EMERGE and ENGAGE) evaluating aducanumab. The combined studies included 3,285 participants with early Alzheimer disease who received one or more doses of placebo (1,087 participants) or aducanumab (2,198 participants) during the placebo-controlled period.
The researchers found that 41.3 percent of patients experienced ARIA during the placebo-controlled period; serious cases occurred in 1.4 percent. The most common adverse event was ARIA-E (35.2 percent); 26.0 percent of patients with an event exhibited symptoms, and 72.7 percent of the initial events occurred within the first eight aducanumab doses. Among patients with symptomatic ARIA-E or ARIA-hemosiderin, common associated symptoms were headache, confusion, dizziness, and nausea (46.6, 14.6, 10.7, and 7.8 percent, respectively). Aducanumab-treated participants who were apolipoprotein E ε4 allele carriers had the highest incidence of ARIA-E. Among those with ARIA-E, most events (98.2 percent) resolved radiographically, and 88.2 percent resolved within 16 weeks. Overall, 19.1 and 14.7 percent of participants had ARIA-microhemorrhage and ARIA-superficial siderosis, respectively.
“In patients with identified ARIA, prescribers should carefully assess the radiographic and clinical findings when deciding whether to continue dosing,” the authors write.
The EMERGE and ENGAGE trials were funded by Biogen; several authors disclosed financial ties to pharmaceutical companies, including Biogen, which manufactures aducanumab.