Biogen, Eli Lilly present new clinical data in race to field Alzheimer’s treatments

The drugmakers are vying for leadership in multibillion-dollar market

Cambridge drug maker Biogen, which won US approval in July for the first Alzheimer’s therapy shown to modestly slow cognitive decline, is advancing a new line of attack on the memory-robbing disease.

Even as it ramps up sales of its approved drug, Leqembi, which clears the buildup of a toxic protein in the brain, Biogen released early clinical data Wednesday for a different drug, called BIIB080, which targets another type of protein, called tau, that is also suspected of contributing to Alzheimer’s disease.

The data, presented at a scientific meeting in Boston, come as Biogen vies with pharmaceutical giant Eli Lilly for leadership in the emerging multibillion-dollar market for Alzheimer’s therapies. The progressive degenerative disease afflicts more than 6.7 million Americans.

In its early-stage study, Biogen’s experimental drug was injected into the spinal canals of 46 patients in Canada, the United Kingdom, Finland, Germany, the Netherlands, and Sweden. The trial was meant to test for safety, but also showed encouraging clinical outcomes, such as reduced tau in the cerebral spinal fluid of 22 patients who completed a long-term study extension at the highest doses, the company said.

“It was slowing cognitive decline and improving clinical outcomes,” Priya Singhal, head of development at Biogen, said in an interview. Most patients who completed the study reported moderate side effects, however, such as headaches and pain, she said.

Biogen chief executive Chris Viehbacher said the early findings were promising enough for the company to continue investing in a larger, mid-stage study involving 700 patients at 140 sites globally. That study will test two different dosing regimens for the experimental drug.

The company acquired the drug candidate from Ionis Pharmaceuticals in 2019. Unlike Leqembi, which uses a bioengineered antibody that works outside the cell to attack the buildup of proteins called beta-amyloid plaques, BIIB080 works inside cells, targeting tau with short, single strands of synthetic RNA known as antisense oligonucleotides.

A similar approach is already used in dozens of approved treatments for cancers, viruses, and rare genetic conditions — including in Spinraza, a Biogen drug that treats spinal muscular atrophy — but has never been successfully tested in Alzheimer’s.

If its tau-targeting treatment eventually wins Food and Drug Administration approval, Viehbacher said Biogen would consider packaging it with Leqembi as a combination therapy to attack both types of proteins tied to Alzheimer’s.

Biogen is marketing Leqembi with its Japanese business partner, Eisai. But the Cambridge company is developing its anti-tau drug on its own.

“If we’re successful, this will be a whole new frontier in the treatment of Alzheimer’s,” Viehbacher said. “We want to be one of the leaders in this space for a long time to come.”

Biogen wasn’t the only drug maker to tout what it called encouraging findings on Wednesday at the 16th annual Clinical Trials on Alzheimer’s Disease conference at the Boston Park Plaza Hotel.

Lilly, based in Indianapolis, is seeking FDA approval of its Alzheimer’s drug candidate donanemab, a once-a-month treatment administered intravenously to patients with early-stage symptoms.

That medicine targets the same protein buildup in the brain as Leqembi but has generated even more impressive results, slowing cognitive and functional decline by about 35 percent over 18 months, compared with a placebo, according to data published in July in the Journal of the American Medical Association. Based on that data, donanemab is widely expected to be approved by the end of the year for people with mild impairment.

Dr. Brandy Matthews, Lilly’s vice president of global and US medical affairs for Alzheimer’s disease, said a follow-up analysis showed that donanemab would likely prolong the ability of patients to retain memories, solve problems, take care of personal needs, continue to engage in hobbies, and even be left alone.

The analysis “showed the impact on specific daily activities that have a relationship to independence, and we know that’s important to patients and their loved ones alike,” Matthews said.

As with Leqembi, patients appeared to get the most benefits from donanemab if they started taking the medicine soon after symptoms appeared and an Alzheimer’s diagnosis was confirmed, Matthews said.