Mighty Biogen (BIIB 1.10%) is a massive biotech, weighing in at $50 billion (market cap). Tiny Cassava Sciences (SAVA 3.38%) is less than one-tenth the size, with a valuation of $4 billion. Both companies are pursuing Alzheimer's drugs.

Alzheimer's is a massive market opportunity -- over $100 billion by some estimates. Biogen recently got its Alzheimer's drug aducanumab approved, even though it failed to beat a placebo and might cause brain bleeds. Cassava's drug, simufilam, is about to enter phase 3 trials later this year.

Which company will ultimately win? Motley Fool editor and analyst Olivia Zitkus and Fool.com writer Taylor Carmichael try to pick the stronger investment for Fools. (But first they have to figure out how to pronounce those drug names.) This Motley Fool Live segment was recorded on July 30.

Taylor Carmichael: One big difference in what Cassava is trying to do is they're not focused on the plaques, the amyloid plaques. This is gene company, they're trying to fix a gene that's broken that you also see in Alzheimer's patients. How do you pronounce it?

Olivia Zitkus: Simufilam.

Taylor Carmichael: That's the drug, but the actual gene is Filamin A?

Olivia Zitkus: Filamin A, yeah.

Taylor Carmichael: I might be mispronouncing it. I don't know how to pronounce it.

Olivia Zitkus: That's OK. That's the risk we run with these biotech and healthcare chats. I looked at a drug name and I'm like, I never said this out loud before. [laughs]

Taylor Carmichael: It's funny because the CEO gave an interview and the interviewer asked him, "Why did you pick such a weird name," and he said, "We didn't pick it, we didn't pick it."

Olivia Zitkus: [laughs]

Taylor Carmichael: They don't actually pick the scientific name for their drug, it's picked for them. Biogen's drug that they put on the market, it's a weird name and I'm like, that's the name you pick? I can't even say it.

Olivia Zitkus: I know. That's the difference between Cassava's drug and Biogen's drug, right? Cassava's drug is a gene therapy and Aduhelm is targeting the amyloid plaque. The other big thing here is that Aduhelm is administered by IV intravenously and simufilam is orally administered in a pill form.

Next video: Here's What Investors Should Know About Cassava's Alzheimer's Drug Candidate