Three-year data from a study of early Alzheimer’s disease (AD) patients on Eisai and Biogen’s Leqembi showed that longer-term use provides continued benefits without additional safety concerns.
The new results are from an extension of an 18-month study, which set up Leqembi for FDA approval last year and showed it reduced cognitive decline by 27% compared to placebo. Among the patients who remained in the trial for an additional 18 months, Leqembi strengthened its showing by cutting average cognitive declines by 31% over 36 months.
While the added benefit is slight, it could help boost continued use of the anti-amyloid beta protofibril antibody and convince physicians to prescribe Leqembi over Eli Lilly’s rival AD treatment Kisunla, which was approved by the FDA four weeks ago. Lilly touts the ability for patients to stop treatment with Kisunla after amyloid plaques are removed from their brains, enabling a reduction in the number of infusions and cost savings.
The Leqembi results were presented Tuesday at the Alzheimer’s Association International Conference (AAIC) in Philadelphia.
They come five days after the European Medicines Agency (EMA) recommended against marketing authorization for Leqembi, triggering a 10% slide in Eisai’s share price. On Wednesday morning, there was no significant change in the company’s share price.
While the EMA rejected Leqembi because it determined that the benefits of the treatment did not outweigh the risk of brain bleeding, the extension study provided evidence that continued use does not increase that risk as most amyloid-related imaging abnormalities (ARIA) occur in the first six months of treatment.
Of those in the extension study, there was a 10% dropout rate due to side effects. It was previously reported that three patients in the extension study died from brain swelling.
The companies also revealed that data from a separate mid-stage study of patients who stopped treatment after 18 months showed that their disease worsened even after the clearance of amyloid plaque. Their rate of cognitive decline matched that of the patients on placebo.
Uptake of Leqembi—which received an accelerated nod from the FDA in January of last year followed by a full approval six months later—has been slow. The companies, which reported Leqembi sales of $19 million in the first three months of this year, each will present their second-quarter figures tomorrow.
While both Leqembi and Kisunla are focused on reducing amyloid plaque in the brain, they go at it in different ways. Leqembi is a dual-action treatment that removes protofibrils, which aggregate in the brain and become amyloid plaque. Meanwhile, treatment with Kisunla, which targets just the plaque, can be discontinued after the plaque is cleared.