AC Immune has reported that an experimental drug, semorinemab, met one of the co-primary goals, ADAS-Cog11, of the Phase II Lauriet clinical trial in mild-to-moderate Alzheimer’s disease (AD) patients.

An anti-tau monoclonal antibody, semorinemab is currently being developed by Genentech and was discovered in partnership with AC Immune.

It acts on the N-terminal portion of the tau protein and can potentially attach to the protein to reduce its spread between neurons.

The double-blind, placebo-controlled, randomised Phase II trial analysed the safety and efficacy of semorinemab against placebo in 272 adults with mild-to-moderate AD enrolled at 43 sites across the world.

The change from baseline at week 49 in cognition as assessed by the Alzheimer’s Disease Assessment Scale, Cognitive Subscale, 11-Item Version (ADAS-Cog11) was one of the co-primary goals.

The other co-primary endpoint was the change from baseline in daily activities as evaluated by the Alzheimer’s Disease Cooperative Study-Activities of Daily Living (ADCS-ADL) scale.

The trial analysed cognitive and functional measures as secondary goals.

Findings showed that semorinemab offered a statistically significant 43.6% decrease in cognitive decline from baseline versus placebo.

The co-primary endpoint of ADCS-ADL was not met in the trial.

As per the top-line data from the trial, the drug was demonstrated to be well-tolerated with a satisfactory safety profile without any unexpected safety signals.

Furthermore, these safety results were in line with already reported data.

AC Immune CEO professor Andrea Pfeifer said: “The top-line results of the Lauriet Phase II 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.

“We look forward to additional data from our other clinical-stage Tau programmes: Tau vaccine ACI-35, partnered with Janssen; and the small molecule Morphomer Tau aggregation inhibitor, partnered with Eli Lilly.”

The open-label portion of the Lauriet trial will progress as planned, Genentech noted.

Additional assessments are underway with top-line results anticipated in November this year.

Apart from the Lauriet trial, semorinemab was evaluated in the Phase II Tauriel study involving early (prodromal-to-mild) AD patients.

The Tauriel study failed to meet the primary efficacy goal, AC Immune and Genentech reported in September 2020.