Dive Insight:

Like many Alzheimer’s drugs in development, donanemab targets a protein called amyloid beta. Research indicates that, when misfolded, these amyloid proteins can clump together and form sticky plaques that lead to neurodegeneration.

Despite massive amounts of time and investment, amyloid-targeting drugs have almost universally failed. AstraZeneca, Johnson & Johnson, Merck & Co. and Roche are just some of the powerful pharmaceutical firms to hit major setbacks getting these medicines to market. Lilly, too, has notched several high-profile defeats of its own.

Yet, with donanemab, Lilly thinks it’s found something promising.

The company touts how donanemab, which actually goes after a modified form of amyloid beta known as N3pG, has been shown to quickly clear amyloid plaques. The way in which the drug works, combined with the positive results from this latest trial, “give us confidence in donanemab and support its rapid and deep plaque clearance for the potential treatment of Alzheimer’s disease,” Daniel Skovronsky, Lilly’s chief scientific officer, said in a Jan. 11 statement.

Skovronsky isn’t alone is his excitement. Al Sandrock, the head scientist at Biogen, said Monday during a presentation at the J.P. Morgan Healthcare Conference that Lilly’s results are good news for Alzheimer’s patients and research, and offer “additional reason to hope” for a disease-modifying therapy. Currently, there are no treatments approved by the Food and Drug Administration for the underlying causes of Alzheimer’s.

Sandrock’s words are perhaps to be expected, since Biogen is awaiting an FDA approval decision for its own amyloid-targeting drug, called aducanumab. He noted how there are many similarities between Biogen’s and Lilly’s drugs, and between the studies designed to prove those drugs’ merits.

Lilly’s trial could also be seen as a double-edged sword, however. Analysts at Cowen & Co. noted, for example, that it was a bit surprising to see Lilly’s drug miss on some of the secondary endpoints, given that trial had such a specific design.

“While it is great to have a successful trial in Alzheimer’s disease, results are mixed,” wrote Steve Scala of Cowen. “The effect size is small despite a tailor-made endpoint, and there were misses on some secondary endpoints, despite donanemab nearly completely wiping out plaques.”