Dr. Holly Fernandez Lynch

There are lots of other surrogates that have not been validated, but we think they're likely to predict benefit.

So for example, you might in the oncology space,

See progression free survival.

Right.

How long do you survive without your disease progressing?

Or you might see things like tumor shrinkage or in the Alzheimer's case, you might have seen in the news some discussion about plaques in the brain.

These are things that you would need to have a lab test or a scan to see whether they're being affected by the drug.

But we think that they're predictive.

We're just not 100% sure.

So FDA can grant approval of drugs based on those unvalidated surrogate measures.

I know that's a lot of jargon, but basically, FDA can grant approval based on the prediction of benefit.

And when it does that, it requires companies to continue studying the product after it's allowed on the market.

So that's one type of flexibility that FDA has where you can get a drug on the market where we're not even really sure that it works, but we hope it does.

It has a lot of discretion in what evidence it's willing to accept to meet that effectiveness standard.

Okay, so the Alzheimer's drug that you're referring to is a drug called Adjuhelm.

It's actually been voluntarily taken off the market by its manufacturer, Biogen.

But it was quite controversial.

It was approved in 2021.

using this accelerated approval pathway that I was just describing.

So it was approved not based on a demonstrated benefit in Alzheimer's disease outcomes, but rather based on the influence of the drug on these plaques in the brain.