On June 7, the Food and Drug Administration (FDA) approved a new drug to treat Alzheimer’s disease. Aducanumab, developed by Biogen, is a monthly infusion treatment aimed at slowing the decline of memory and thinking skills in people in the early stages of Alzheimer’s disease with mild cognitive impairment or mild dementia.
“This is a landmark decision in several respects as aducanumab is the first novel therapy approved for Alzheimer’s in 18 years and the first drug attacking the underlying pathobiology,” said Pierre Tariot, MD, Director of the Banner Alzheimer’s Institute in Phoenix.
The drug, which will go by the name Aduhelm, has had its ups and downs during clinical trials and FDA review. The FDA approved the drug despite the fact that many researchers, including the FDA’s independent review committee, did not conclude the data supported its effectiveness.
Thus, the FDA approved the drug with the caveat that Biogen must perform another clinical trial while the drug is available to the public. If the results of the trial do not uphold the efficacy of the drug, the FDA could, but is not required to, remove their approval.
Aducanumab was studied in two identical trials. The studies had different findings, however, which led researchers and Alzheimer’s advocates to reach diverse opinions about its approval.
The trials were halted early after a planned review showed the drug was not meeting expectations. After additional evaluation of the study data, Biogen reported that one trial did show cognitive decline by 22 percent for participants who completed 78 weeks of treatment. The study also reported a drop in amyloid plaque buildup in the brain, thought to be the signature of Alzheimer’s disease. However, the second trial did not see these benefits.
In November of 2020, the FDA’s Advisory Committee voted against approving aducanumab, saying there was inconclusive data to show the drug slowed memory and thinking. In January 2021 Biogen submitted additional data and analyses to the FDA, who delayed their decision from March until June. Now eyes turn to the Centers for Medicare and Medicaid Services (CMS) to determine coverage for Aduhelm, which is estimated to cost $56,000 annually.
Some researchers spoke out against the drug, stating concerns about the data and safety risks. Alzheimer’s community advocates, on the other hand, encouraged the FDA to approve the drug since it is the first promising treatment for Alzheimer’s disease since 2003.
There are also questions about who the drug may actually benefit. The positive results were seen in only a small subset of trial participants. The trials also identified an increased risk of brain swelling and bleeding.
“This was an extremely difficult judgment to make. I take the FDA statement at face value,” said Dr. Tariot. “The evidence that aducanumab reduces brain amyloid is clear, but the filing data were ‘highly complex and left residual uncertainties regarding clinical benefit’ and the FDA ‘examined the clinical trial findings with a fine-tooth comb’.”
Even with the caveats mentioned, aducanumab is certainly the most promising drug to come along to treat Alzheimer’s in quite a while. Many scientists believe its discovery brings hope for more effective treatments in the future.