Biogen Idec shares up on positive early-stage results for Alzheimer's candidate aducanumab

US biotech major Biogen Idec (Nasdaq: BIIB) has announced data from a pre-specified interim analysis of PRIME, the Phase Ib study of aducanumab (BIIB037), in which aducanumab demonstrated an acceptable safety profile and positive results on radiologic and clinical measurements in patients with prodromal or mild Alzheimer’s disease (AD).

News of the positive results sent Biogen Idec’s surging in premarket trading, with the stock up 6.4% at $461.37 shortly after trading opened. These data are being presented today at the 12th International Conference on Alzheimer's and Parkinson's Diseases and Related Neurological Disorders in Nice, France.

Treatment with aducanumab produced a dose- and time-dependent reduction of amyloid plaque in the brain. Amyloid plaque is believed to play a key role in the development of the symptoms of AD. In exploratory analyses, a dose-dependent, statistically significant effect of slowing clinical decline was observed on the Mini Mental State Examination (MMSE) and Clinical Dementia Rating (CDR) scales. On the CDR scale, a key measure of cognition, BIIB037 at the high dose demonstrated a 71% reduction in decline compared to a placebo after 54 weeks.