Thoughts on the FDA approval of aducanumab to treat Alzheimer’s disease

Alzheimer’s was in the spotlight this week due to the FDA’s controversial decision to approve the drug aducanumab for treatment of the disease. I’ve closely followed the debate and can understand why some hope this is the breakthrough drug we’ve all been waiting for while also agreeing with critics who question the FDA approval process for this drug due to the limited evidence of its effectiveness in trials. There’s also the hefty price tag to consider.

Choosing whether to take a medication or undergo a treatment is a personal decision that should be made with the consult of family and trusted physicians familiar with the individual’s case. Below I’ll go over some general takeaways to consider. If you know of someone who was in the trial I’d love to hear about their experience.

Target treatment group: Aducanumab has so far only been studied in people living with early Alzheimer’s disease and mild cognitive impairment (MCI) due to Alzheimer’s. The FDA approval will allow it to be prescribed to those at any stage of the disease.

How it works: Aducanumab targets the amyloid beta plaque in the brain with the goal of reducing the plaque buildup and slow the rate of cognitive and functional decline.

How effective is it? This is where the main controversy arises. Biogen, the maker of aducanumab, was only able to provide very modest evidence that the drug offers a tangible benefit. “The average degree of improvement on a 0-18 point cognitive scale was just 0.39 points relative to placebo, far smaller than the 1 or 2 point threshold typically used to define a clinically important difference,” according to the two physicians who wrote this Washington Post opinion piece. Trials of the drug were halted in 2019 because an analysis concluded the trials were unlikely to be successful in hitting their goals at completion. But months later, after analyzing a wider set of data and discovering the nominal improvement, Biogen announced it was seeking FDA approval of aducanumab, CNN reported. After an FDA panel voted overwhelmingly to not recommended that drug approval move forward, the FDA eventually greenlighted aducanumab.

The drug was granted Fast Track designation and approved using the accelerated approval pathway, which only requires a “reasonably likely to predict a clinical benefit to patients” and also requires a post-approval trial to verify that the “drug provides the expected clinical benefit.”

What are the side effects? The most common side effects of aducanumab  were “headache, fall, diarrhea, and confusion/delirium/altered mental status/disorientation,” according to the FDA. Brain swelling was also reported by some trial participants.

How expensive is it? Very expensive. The drug is expected to cost $56,000 per year. Part of the expense is in how the drug must be delivered, via infusion every four weeks. There may also be expensive imaging tests required to begin treatment. While insurance companies are expected to pay for some of the cost, it is unclear how much Medicare will reimburse, CNN reported.

What are the general expectations? Those who take aducanumab may see modest improvements in cognitive functioning or see a reduction in the speed of decline in cognitive functioning. It’s important to note that while the drug may remove amyloid plaque from the brain, that doesn’t guarantee an improvement in cognitive functioning. Advocates see it as a treatment with potential, but not a cure. Aducanumab is the first drug to treat Alzheimer’s disease that the FDA has approved since 2003. It has been a long wait, and that is why the drug’s approval has been met with a mixture of hope and skepticism.