Biogen’s New Alzheimer’s Drug Shows Promise

BiogenBiogen Idec, a pioneer in the biotech industry that develops treatments for neurodegenerative diseases and other medical conditions, made news last Friday when it announced the success of a new drug for Alzheimer’s disease. The PRIME study demonstrated positive results of aducanumab in patients with pre-onset symptoms and mild-Alzheimer’s disease, which represents an outstanding breakthrough in Alzheimer’s research.

The PRIME trial evaluated the effects of aducanumab in 166 people in a Phase 1b randomized, double-blind, placebo-controlled study. Scientists gathered data for multiple dosages of a placebo versus the aducanumab drug, ranging from 1 mg/kg to 10 mg/kg for 30 weeks or 54 weeks.

Researchers used a positron emission tomography (PET) scan with a radiotracer that binds to amyloid plaque on the patients and found that aducanumab had both a dose and time dependent effect in reducing the amount of amyloid plaque in the brain, meaning higher doses over a longer period of time showed stronger results. The placebo had virtually no effect, while the aducanumab treatment showed a significant reduction of amyloid plaque at 3 mg/kg, 6 mg/kg and 10 mg/kg after 26 weeks. At week 54, there were still plaque reductions at 3 mg/kg and 10 mg/kg; data for 6 mg/kg after 54 weeks is still ongoing.

To assess the drug’s effects on cognitive decline, the researchers used the mini-mental state examination (MMSE) to determine the patient’s cognitive status and the Clinical Dementia Rating sum of boxes (CDR-SB) to characterize the individual’s cognitive and functional performance. Patients who received the placebo worsened by an average of 3.14 on the MMSE after one year, while patients who received aducanumab worsened by 2.21 with 1 mg/kg dosage, 0.75 with the 3 mg/kg dose and 0.58 with the 10 mg/kg dose. This showed significant slowing of cognitive decline as compared with the placebo.

After one year, patients in the placebo group worsened by 2.04 on the CDR-SB. Those in the aducanumab group worsened by 1.70 for the 1 mg/kg dose, 1.33 for the 3 mg/kg dose and 0.59 for the 10 mg/kg dose. Once again, all dosages showed significant slowing of cognitive decline as compared to the placebo; these impressive findings exceeded the trials’ already high expectations.

The trial found that aducanumab has some side effects, but demonstrated acceptable safety for human usage. The main side effect observed in the trial was Amyloid-related imaging abnormalities, or ARIA. As amyloid plaques are removed from the brain, blood vessels can become leaky. However, this was generally seen early in treatment and with only mild symptoms. Another negative side effect was that 22% of those using the drug had frequent headaches, while only 5% receiving the placebo did.

Aducanumab is a human recombinant monoclonal antibody gathered from a population of healthy elderly donors who are cognitively stable. At this time, it is still an investigational treatment for Alzheimer’s disease. Scientists caution that it may be difficult to foretell the drug’s impact with data from a Phase 1 trial and small study group. They are looking forward to results from a late stage study that will start later this year.