One of the strange aspects of the Biogen (BIIB 0.78%) saga is that the Food and Drug Administration is requiring the company to run yet another study to see if the company's Alzheimer's drug, Aduhelm, actually helps patients. Requiring an additional study because you haven't proved efficacy seems like a tentative approval, like an FDA maybe or an FDA wishful thought.

It's kind of analogous to an Emergency Use Authorization (EUA), in that it implies that the FDA is not yet certain about this drug. Of course, Alzheimer's isn't an emergency, unlike the COVID-19 vaccines. And while the COVID vaccines might have been rushed to market, all those companies definitely had to prove safety and efficacy, and did so. With Aduhelm, the FDA is allowing a drug on the market, in a non-emergency situation, when it might not work at all. And Biogen's drug causes brain bleeds in some patients. So yes, this drug could very well be withdrawn from the market one day.

Motley Fool editor and analyst Olivia Zitkus and writer Taylor Carmichael had a virtual chat about this topic. This Fool Live segment was recorded on July 30.

Taylor Carmichael: What the FDA has said is: "You're going to have to do another study to prove efficacy. If this study fails to prove efficacy, we're going to pull the drug from the market." But they're giving them years to do the study. This is almost like a charitable contribution to Biogen. They spent billions trying to get this drug approved and got it approved, and now they are trying to make a lot of money off of it, almost like they're afraid it's going to be pulled from the market.

Olivia Zitkus: Right. Yeah. They have already made $2 million from Aduhelm, which was just approved on June 7, right? In the context of its current revenues -- which for the quarter, you've got Biogen's MS drug, Ocrevus, bringing in $1.78 billion and total revenue of $2.77 billion -- so right now, it's just a blip on the radar. But are they hoping to just sell until they can't anymore?

Taylor Carmichael: Typically, for a biotech company, drug approval is everything. Once it gets approved, you feel like the rest of it is a cakewalk because the real difficulty is getting your drug approved by the FDA. That's what kills so many biotech stocks. Normally, drug approval, everybody's cheering and happy and good, and this was weird because everybody is suspicious and angry and worked up. The stock, I think, doubled the day of the approval or close to it. It had a very significant gain. But potentially, it's a massive blockbuster drug. The downside: They might not get Medicare reimbursement, they might not get private health plans' reimbursement because so many doctors are opposed to this drug and think it doesn't work. At best, all it's going to do is slow the decline. All it's going to do is, your family member on Alzheimer's is going to continue to get worse, just not as quickly. It's not a cure. It doesn't make patients better. It just slows the decline, at best. They're not even sure if it does that. Right now, all they really know is that it reduces amyloid plaque.