AC Immune’s Stock Climbs Following Mixed Phase 2 Trial Results for Alzheimer’s Disease Drug

Alzheimer’s disease (AD) treatments have received a lot of attention this year after the historic and controversial approval of Aduhelm by the FDA. The therapy was approved based on two Phase 3 clinical trials, the results of which are hotly disputed in the community. However, only in one of the trials, Aduhelm reduced cognitive decline. The treatment successfully reduced the levels of amyloid-beta, a protein that accumulates in the brains of AD patients.

The approval was met with controversy because of a lack of clear benefits for the patients and the high cost of the drug. Currently priced at $56,000 a year, the cost has led insurers to announce they would not cover the drug. Medicare has now begun a national review to determine conditions for nationwide coverage. If met with an unfavorable decision, patients might not be reimbursed for the treatment. 

New therapies for AD are necessary since there is a large unmet need. Additionally, the number of people aged 65 and older with AD is expected to grow past 10 million over the next decades. For this reason, the AD community is eager for new therapeutic options, and companies are racing to develop them.

Although a lot of attention is given to amyloid-beta, another top suspect in AD disease is the Tau protein, which accumulates in the brain and forms tangles damaging the neurons. AC Immune, a Switzerland-based company, has developed a monoclonal antibody, semorinemab, to bind to tau and slow its spread between neurons.

On August 31st, AC Immune announced that semorinemab met one of its primary endpoints of a Phase 2 trial, reducing cognitive decline by 43.6% compared to placebo as measured by a cognitive test.  The news sent its stock more than 70% higher at the opening bell. At the end of the session, the stock was still 18.7% higher than the previous session.

Promising Results From Phase 2 Lauriet Trial

AC Immune specializes in developing precision medicines for neurodegenerative diseases. Their pipeline includes several diagnostic compounds and therapeutics in clinical trials. Two of their most advanced products include a monoclonal antibody-based therapy and a vaccine, both against amyloid-beta. Both candidates are now in Phase 2 trials.

Another therapeutic target being investigated by AC Immune, in collaboration with Genentech, is semorinemab, their anti-tau antibody. In the Phase 2 Lauriet trial, semorinemab successfully reduced cognitive decline at week 49 as measured by the Alzheimer’s Disease Assessment Scale, Cognitive Subscale, 11-item Version (ADAS-Cog11) in patients with mild-to-moderate AD.

The therapy did not meet its second co-primary endpoint of reducing cognitive decline as measured by a different test, and it did not meet its secondary endpoints. Additionally, the antibody was well tolerated. The open-label portion of the study will continue as planned.

Prof. Andrea Pfeifer, CEO of AC Immune, expressed guarded excitement over the results.

“The top-line results of the Lauriet Phase 2 clinical trial of semorinemab are remarkable in that it is the first time we have seen a therapeutic effect by a monoclonal anti-Tau antibody therapy. We also are excited by the fact that this is the first time a monoclonal antibody has had a therapeutic impact on cognition in the mild-to-moderate AD patient population,” he said.

“Nevertheless, despite these interesting results, we are still cautious about what this may mean for patients as there was not an impact on the rate of functional decline or other efficacy endpoints…” he added.

Author

Daniel Ojeda