2nd Alzheimer's vaccine by AFFiRiS

Apr 17 2008

The Viennese biotech company Affiris is today taking stock of the progress achieved to date in its clinical Alzheimer's vaccination programme. All the Alzheimer's patients treated so far as part of the toxicological trials have tolerated the treatment extremely well. As a result, Affiris is among the leading international centres in the race to develop the first causal immunotherapy for Alzheimer's disease.

Due to the dramatic increase in the number of Alzheimer's cases, new and more effective treatments are urgently needed. The medicines that are currently in use are of limited value as they can only alleviate the symptoms of the disease temporarily, for a period of around one to two years, and are ultimately unable to prevent the onset of dementia. However, the Viennese biotech company Affiris is pursuing a new approach, which is yielding extremely promising results. The company is using an innovative Alzheimer¹s vaccine not just to target the symptoms of the disease, but in the hope of directly modifying the disease process in the brain of Alzheimer's patients.

Safety is the number one priority in the current clinical trials that are being carried out on patients. "The current studies are focused on establishing the safety and tolerability of the new vaccines," emphasises Prof. Achim Schneeberger, Head of Clinical Department at Affiris. The new vaccines are currently being tested in two Alzheimer's trials.

The AFFiRiS 001 trial is being staged at the Vienna General Hospital (AKH) and is testing the vaccine AFFITOP AD01. The AFFiRiS 002 trial of the vaccine AD02 is being conducted at the Institute of Psychosomatic Medicine, Vienna. Although the two vaccines have different active ingredients ­ the antigenic peptide ­ both trials are virtually identical in terms of their design.

Interim toxicity findings from the AFFiRiS 001 trial, which began in September 2007 and involves to date 9 Alzheimer¹s patients with mild to moderate dementia, indicate that the innovative immunotherapy is safe. Prof. Schneeberger explains: "All the patients have thus far tolerated the vaccines extremely well, as expected." The AFFiRiS 002 sister trial also got off to a similarly promising start at the end of February 2008 - all of the Alzheimer¹s patients that have been involved in the trial have also received and tolerated their first vaccinations.

The Aß amyloid is the main component in the protein deposits (amyloid plaques) that are characteristic of Alzheimer's dementia. The accumulation of this amyloid in the form of neurotoxic aggregates destroys brain cells and causes the typical symptoms of Alzheimer's disease. During the 2001 trial of a previous Alzheimer's vaccine called AN1792, which was conducted by the U.S. and Irish pharmaceutical alliance ELAN-Wyeth, patients suffered severe inflammation of the brain and the trial was immediately halted.

Despite this, follow-up analyses showed that the vaccine had been effective in some of the patients. Around 20 percent of those who received the vaccine developed antibodies that protected against the Aß amyloid and disease progression was halted in a number of the patients.

"Our Vienna-based research group is in the process of modifying the immunogen for the vaccine," explains Prof. Schneeberger. Scientists at Affiris are also using an ingenious approach based on the principle of molecular mimicry to exclude potential unwanted side effects in advance.

This technology allows the intended immune reaction to be accurately directed against harmful protein deposits. A multifaceted approach to safety means that this "immunological camouflage" is supported by a combination of additional safety components developed by Affiris. These include the immunogenic peptide, a carrier protein and a proven and safe adjuvant (vaccine additive). The peptides in use are short mimotopes of the Aß amyloid that are between six and seven amino acids long. While this should permit the breakup of harmful proteins in the brain, it should also prevent any undesired immune reactions. An animal model used by Affiris for Alzheimer¹s dementia not only confirmed that the vaccine can reduce amyloid plaques by around 70 percent, but also showed that the animals performed significantly better in brain function tests after treatment. The first clinical trials on Alzheimer's patients have now also indicated that this concept works extremely well. As all the patients treated so far have tolerated the vaccine without any noteworthy complications, the way is now open for the next stage of testing. This milestone also means that the vaccine developed by Affiris is one of the best hopes in the fight against Alzheimer's disease.

Affiris is a young and innovative Vienna-based biotechnology company which has been operating from Campus Vienna Biocenter since 2003 and employs more than 30 highly skilled staff. The company has an international outlook and collaborates with partner centres in Germany, Spain, the U.K. and the U.S.

"Our research work focuses on the development of treatments for diseases that urgently require a medical solution. Alongside the Alzheimer's programme, we at Affiris are also working to develop and make available new medicines for the treatment of other major diseases such as atherosclerosis in the near future," explains scientist, founding member and CEO of Affiris GmbH, Dr. Walter Schmidt.