Affiris AD02 Alzheimers Vaccine Has Positive Phase I Results
After initially meeting the primary endpoints of Phase I clinical testing by demonstrating safety and tolerability, the AD02 Alzheimer’s vaccine candidate by AFFiRiS AG has surprised researchers with further unexpected findings. The drug has had positive effects on the cognitive performance of patients enrolled in the trial, their body weight and immune reaction.
The vaccines are based on peptides which imitate the beta amyloid protein found at high levels in the brains of Alzheimer’s patients and are intended to trigger an immune reaction.
For the Phase I trial, 24 patients received the vaccine during the 18-month test period. Twelve were given an enhanced vaccine while the remaining 12 received only the ordinary vaccine. Cognitive skills were recorded on a scale from 0 to 30 using the Mini-Mental State Examination (MMSE) Test. The lower the number, the more the disease had progressed.
Nine of the 12 patients receiving the adjuvanted AD02 showed more stable cognitive skills. The skills were surprisingly constant and long term; however, the vaccine only proved effective for those who began the study at an MMSE score of 20 or above.
Typically, Alzheimer patients lose weight during the course of the disease, due to factors such as an altered sense of taste and simply forgetting to eat. Patients treated with adjuvanted AD02 experienced a stabilization of body weight as well.
Per Dr. Walter Schmidt, CEP and co-founder of AFFiRiS, adverse events were mild to moderate in nature, such as pain at the injection site and itching.
“We have to be extremely careful when looking at these results and even more cautious in presenting them,” said Dr. Schmidt. “It is important to keep in mind that the promising Phase I data with AD02 have been observed in a relatively small cohort of 24 subjects only.”
Dr. Schmidt says that active Phase II studies which began last year are designed to further investigate and reproduce the positive outcome. Clinical tests will be conducted on about 420 patients in Austria and five other countries and could yield more evidence on potential effectiveness by the end of 2012.
GlaxoKlineSmith Biologicals (GKS) is a licensing partner for the potential vaccine.
Pfizer and Johnson & Johnson are co-developers of another experimental Alzheimer’s vaccine called bapineuzumab. This drug appears to bind to soluble amyloid and neutralize its toxic effects, preventing it from binding to neurons.
In animal studies, the results of which were presented at an Alzheimer’s and Parkinson’s disease conference in Barcelona, mice that are prone to forming amyloid plaques and have trouble learning fear (a proxy for cognitive function) were injected with bapineuzumab prior to plaque formation. Those injected were found to have the cognitive deficit reversed to a level that was comparable to healthy mice, says Gene Kinney, head of research at J&J’s Janssen Alzheimer Immunotherapy R&D group.
Bapineuzumab, which is in late-stage human testing, has shown limited efficacy in earlier stage trials and encountered a safety setback in 2009.