By Ludwig Burger

FRANKFURT (Reuters) – An Alzheimer’s vaccine developed by a privately held Slovakian biotech firm showed early signs of efficacy in a mid-stage trial, a rare step forward in the fight against the brain-wasting disease, the company said on Monday.

Axon Neuroscience said its AADvac1 drug, which targets pathological changes in the brain to the so-called tau protein that is a hallmark of the disease, slowed deterioration in trial patients when compared with a reference group given a placebo.

The search for an effective drug against Alzheimer’s dementia, which affects about 5.8 million Americans, has so far resulted in a string of high-profile failures, many in the third and last phase, despite the involvement of several major pharmaceutical players.

The close-to-200 participants in the Axon trial, in eight European countries, were between 50 and 85 years of age and had shown early signs of the disease, which affects memory and language as it progresses.

Among younger participants in the trial, a number of assessments of cognitive abilities, including memory, orientation and performing everyday tasks, showed “positive signals” for those on AADvac1 versus those that were not, Axon said.

A blood test measuring neurodegeneration, known as Neurofilament Light Chain (NfL), indicated a “marked slowdown” of deterioration across the age range, it said, adding that the reading was statistically reliable.

The trial was in the second of three phases of testing typically required for regulatory approval.

Axon would now look to sign a collaboration agreement with a global drug company to fund larger trials in the third phase of testing, which is typically the most costly, it said.

AADvac1 was shown to be safe and well-tolerated in the 24-month trial, Axon added.

“These results, which strongly reveal a disease-modifying effect on the disease, underpin our confidence to take the next steps in bringing a life-changing treatment to patients as soon as possible,” Chief Executive Michal Fresser said in the statement.

Axon was established in 1999 with Slovakian neuroscientist Michal Novak, who had previously worked at the University of Cambridge, among other institutions, as a co-founder.

Backed by Slovakian businessman Mario Hoffmann, Axon has a staff of about 110, most of whom are based in Bratislava.

Finding an effective treatment for Alzheimer’s is a compelling target for drugmakers, as the numbers affected across the globe swell with an aging population.

Among the most recent setbacks in the search for a cure, Biogen and partner Eisai ended two late-stage trials in March, wiping billions off their market value. Similarly, Roche and partner AC Immune SA in January gave up on two trials they had held high hopes for.

The failures undermined the so-called amyloid beta treatment hypothesis, in which protein plaques in the brain are believed to play a pivotal role in the disease.

Attempts to target tau, another protein that is more closely linked with the onset of Alzheimer’s symptoms, have come to the fore but trials are at early stages.

Companies with tau drugs in development include Roche, AC Immune, Biogen and Eli Lilly.

Alzheimer’s treatments currently available can only ease the symptoms of the disease, without slowing progression.

AADvac1 is designed to prevent malformed tau proteins from spreading and sticking together in Alzheimer’s patients’ brains, keeping them from forming tangles that disrupt signaling between nerve cells.

(Reporting by Ludwig Burger; Editing by Alex Richardson)

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