The FDA has approved a new starting dosage regimen for the subcutaneous formulation of lecanemab (Leqembi Iqlik, Eisai Inc.), an amyloid-beta-directed antibody indicated for treating adult patients with Alzheimer’s disease (AD).

The drug was previously approved only as an intravenous (IV) starting dose, with an option to transition to IV or subcutaneous maintenance dosage after 18 months of treatment.

This new action marks the first time patients can start treatment with home administration by themselves or their caregiver, the FDA said in a statement.

"Subcutaneous approval is an important step toward the kind of scalable care model Alzheimer's will need as the field moves from single-drug treatment toward combination therapies,” Laura Nisenbaum, PhD, interim chief science officer of the Alzheimer’s Drug Discovery Foundation (ADDF), said in a statement to Medscape Medical News. 

Isobel Coleman, chief executive officer of the ADDF, said in a statement that the approval represents "an inflection point" for Alzheimer’s treatment.

“As therapies become easier to administer, they create an opportunity to fundamentally rethink how we approach this disease, moving toward more dynamic treatment strategies in which therapies can be introduced, adjusted, and combined over time based on how the disease progresses in each individual," Coleman said. The effectiveness of lecanemab in slowing cognitive decline was demonstrated in two large, randomized, placebo-controlled clinical trials in patients with confirmed amyloid pathology and mild cognitive impairment or mild dementia due to AD.

Both studies evaluated lecanemab 10 mg/kg given once every 2 weeks by IV infusion over an 18-month treatment period, with an option for patients to continue in a longer-term follow-up phase.

The starting dose of subcutaneously administered lecanemab is 500 mg (two 250 mg injections) once every week. The maintenance dose regimen is 360 mg once every week.

The subcutaneous formulation was not evaluated separately in large clinical outcome trials, but its effectiveness is supported by the proven effectiveness of the IV formulation in clinical trials, coupled with evidence that the subcutaneous formulation produced equivalent results in the body and similar reductions in amyloid plaques as the IV formulation, the FDA said.

The most common side effects of IV lecanemab are headache, infusion-related reactions, and amyloid-related imaging abnormalities, a side effect known to occur with the class of antibodies targeting amyloid.

Side effects with the subcutaneous formulation of the drug include injection-related reactions, most of which are localized at the site of the injection and can include redness, swelling, rash, pain, and/or bruising.

Subcutaneous lecanemab received priority review by the FDA.