Alzheimer’s drug denied accelerated approval by the FDA

Jan. 23, 2023

The U.S. Food and Drug Administration (FDA) has denied accelerated approval for the investigational anti-amyloid donanemab (Eli Lilly) for the treatment of early Alzheimer's disease (AD) because of insufficient data, the manufacturer has announced.

In a press release, the company reported the FDA issued a complete response letter requesting that Lilly provide data from at least 100 patients who received a minimum of 12 months of continued treatment of donanemab. 

The data are part of the Phase 3 TRAILBLAZER-ALZ 2 trial, and most of the results will be available by the second quarter of 2023, the company said. 

“While the trial included more than 100 patients treated with donanemab, due to the speed of plaque reduction, many patients were able to stop dosing as early as six months of treatment, resulting in fewer than 100 patients receiving 12 months of donanemab,” Lilly's press release noted. 

“The FDA indicated that the data to meet the exposure exception would likely need to include the unblinded controlled safety data from TRAILBLAZER ALZ 2 upon completion,” it added. 

The Alzheimer's Association noted in a statement that “the donanemab Phase 2 Alzheimer's trial showed significant slowing of decline on a measure of memory, thinking, and daily function” compared with placebo in patients with early AD. 

“On behalf of our constituents, we look forward to the Phase 3 trial top-line data readout expected later this year, and the outcome of ongoing discussions between the company and the FDA,” the organization said. 

The delay of donanemab's fast-tracked approval follows on the heels of the FDA's approval earlier this month of the anti-amyloid lecanemab (Leqembi, Eisai) for the treatment of early AD, as reported at the time by Medscape Medical News

The FDA approved lecanemab on January 6 based on results from the CLARITY AD trial, which showed that the drug reduced amyloid markers in early AD, and resulted in moderately less decline in cognition and function than placebo at 18 months. However, it was also associated with several adverse events. 

As for donanemab, Howard Fillit, MD, cofounder and chief science officer of the Alzheimer's Drug Discovery Foundation (ADDF), commented in a press release that the drug “did what it was intended to do” — remove amyloid plaques in the brain. 

“And because of the trial's innovative design, treatment was halted for patients once the biomarker PET scans confirmed the plaques were gone. In some cases, this occurred in less than 12 months, which is why fewer patients stayed on the drug for a full year,” he noted. 

Medscape Medical News release