Phase 2 data showing a reduction in amyloid-beta plaques in early Alzheimer's patients is good enough for FDA to give it temporary approval under their Accelerated Approval pathway.

The positive results occurred in mild cognitive impairment or mild dementia patients. Lecanemab-irmb is a 100 mg/mL injection for intravenous use, a humanized immunoglobulin gamma 1 (IgG1) monoclonal antibody directed against aggregated soluble (“protofibril”) and insoluble forms of amyloid beta (Aβ) for the treatment of Alzheimer’s disease (AD). The approval is based on Phase 2 data that demonstrated that LEQEMBI reduced the accumulation of Aβ plaque in the brain, a defining feature of Alzheimer's Disease.

The safety of LEQEMBI has been evaluated in 763 patients who received at least one dose of LEQEMBI in Study 201. The most common adverse reactions reported in at least 5% of patients treated with LEQEMBI 10 mg/kg biweekly (N=161) and at least 2% higher incidence than patients on placebo (N=245) were infusion-related reactions (LEQEMBI 20%; placebo 3%), headache (LEQEMBI 14%; placebo 10%), ARIA-E (LEQEMBI 10%; placebo 1%), cough (LEQEMBI, 9%; placebo, 5%) and diarrhea (LEQEMBI, 8%; placebo, 5%). The most common adverse reaction leading to discontinuation of LEQEMBI was infusion-related reactions that led to discontinuation in 2% (4/161) of patients treated with LEQEMBI compared to 1% (2/245) of patients on placebo.

Using the recently published data from the large global confirmatory Phase 3 clinical trial, Clarity AD, Eisai will work quickly to file a Supplemental Biologics License Application (sBLA) to the FDA for approval under the traditional pathway.