Biogen Idec Inc (NASDAQ:BIIB) drug that attacks plaque buildup in the human brain slowed cognitive decline in patients that were in early phase of Alzheimer disease. The results were revealed in a small, early-stage study carried out by the company that tracked patients over 54 weeks. The news took Biogen’s share price to all-time highs.

In December, Biogen stated that its drug named ‘aducanumab’ resulted in a statistically noteworthy effect on cognition and intends to commence a late-stage trial later this year that will include over 1,000 patients. It used two cognitive tests in early stage trial to evaluate aducanumab’s clinical effect on patients.

The drug also called as “BIIB037,” is developed to clear beta amyloid plaques in the brain, which many scientists believe play a crucial role in causing Alzheimer disease. The problem is associated with a progressive, memory-destroying state associated with older age.

The study is based on controversial “amyloid hypothesis.” In previous studies, the drugs targeted at plaques in brain have failed in late-stage trials.

The first stage trial was designed to assess aducanumab’s safety, which Biogen stated was acceptable. The patients treated with the drug showed fluid buildup around blood vessels and 22% of enrollments experienced headaches, against 5% of patients receiving placebos. The effects on cognitive ability were stated as “exploratory” study endpoints.

The drug still needs longer and larger drug studies, and as of now is not considered suitable for all patients. However, the trial results were encouraging for observers as the drug’s effects were consistent in first phase trials. The consistency improved with higher doses. Also, brain imaging scans showed significant plaque reduction that correlated with clinical improvements. Biogen, known for its multiple sclerosis therapies, reported sales of $9.7 billion last year.

While still very early, the first phase data are impressive, supporting the pre-data excitement. It could act as an innovative disease-modifying therapy for Alzheimer patients.