The United States food and Drug Administration has approved the first new treatment for Alzheimer's disease, Aducanumab, which targets the underlying cause of Alzheimer's, the most common form of dementia, rather than its symptoms.

The treatment is the first to get approved after nearly two decades of failed efforts. The approval from FDA paves the way for its approval around the world.

Despite this is a bright light and is welcomed by charities and patient groups across the world, there has been underlying controversy relating to the treatment.

Some Experts and even FDA independent advisor committee have advised against the approval of the vaccine.

Aducanumab, however, is suitable for only those patients with mild Alzheimer's when the brain function is still limited. 

Dr. G. Caleb Alexander of James Hopkins Bloomberg School of Public Health said to BBC he was shocked that the treatment was approved by the FDA.

"I think the jury is still out regarding this product and there's a remarkable amount of uncertainty regarding the totality of the evidence as to whether it's truly effective or not," he said.

"I was part of a scientific advisory committee, late last year, and there was virtual consensus among the committee that there was not persuasive evidence which is a regulatory threshold," Alexander said.