On the 7th June, the US FDA held a special meeting and approved an experimental drug called aducanumab for the treatment of Alzheimer’s. This decision represents a major milestone for neurodegenerative research, as it is the first disease-modifying treatment for dementia. But the decision has not been an easy one.

In March 2019, the biotech company Biogen announced that they were stopping two phase 3 investigational studies of aducanumab, which the company had been developing to treat Alzheimer’s. The initial data from both studies indicated that the drug was not having any effect in slowing the progression of the condition. The news was a crushing blow for the company and the Alzheimer’s community who had high hopes for the trials.

However, when further data was collected as the two studies were winding down, analysis of the aggregated results suggested that the therapy was actually having a positive impact in one of the studies. Participants who received the highest dose of aducanumab in one of the studies demonstrated statistically significant improvement in a clinical measurement of their dementia. But this data conflicted with the results of the second ‘identical design’ study in which the drug did not show any clinical efficacy.

The positive findings of the first study excited the Alzheimer’s community, and Biogen approached the US Food and Drug Administration (FDA) to ask for approval for clinical use based on the new data. A review process has been underway since, and on the 7th June the FDA approved aducanumab. This outcome has major implications for the field of neurodegenerative research.

The FDA’s decision to approve aducanumab was a difficult one because, back in November 2020, an independent scientific panel voted overwhelmingly against approving it. They argued that the existing clinical trial data were not enough to prove efficacy against Alzheimer’s. In addition, there was the issue of the conflicting data between the two phase 3 studies, which may indicate that the drug only works in a yet to be identified sub-population of sufferers.

This scientific debate has been conducted in parallel with strong, impassioned calls for approval from the Alzheimer’s community who are desperate for any potential disease-modifying treatment. Now that the FDA has approved aducanumab, there are concerns and questions regarding the roll-out of the drug. Will doctors prescribe the drug based on the current data? Will health insurance companies in the U.S pay for the treatment, which may carry a significant cost?

It remains to be seen how the treatment plan is implemented. The case of aducanumab represents an important learning experience regarding the obstacles and hurdles that need to be addressed and cleared in order to get novel treatments into clinical use; and this is specifically the case at Cure Parkinson’s where the research team is keen to understand the implications for Parkinson’s.