Both Pfizer (NYSE:PFE) and Merck (NYSE:MRK) have recently announced they're advancing oral antiviral candidates targeting COVID-19 into late-stage testing. In this Motley Fool Live video recorded on Sept. 8, 2021, Motley Fool contributors Keith Speights and Brian Orelli discuss if the two drugmakers could be big winners with their COVID-19 pills.

Keith Speights: So, let's switch to a different story. This is different from COVID-19 vaccines. But Pfizer, ticker is PFE, and Merck, ticker there is MRK. Both of these companies, big drugmakers, they're both moving forward with late-stage clinical studies of oral antiviral candidates that target COVID-19.

Brian, do you think both of these companies could potentially be big winners with their COVID-19 pills?

Brian Orelli: Yeah, I think they could be huge winners even this late in the game. The reason is that we're always going to have a few people who don't get vaccinated, or get vaccinated but get a breakthrough case that's somewhat serious. Then, as you were mentioning earlier, the pandemic may end, but we may be endemic at some point and we'll just have the coronavirus around all the time, just like we have flu around all the time.

I think if Pfizer and Merck are successful, I think they could probably charge a lot for these treatments considering the potential life-threatening nature of COVID-19. Even if there's only a small number of people, I think there's probably a potential for them to have a billion dollars in sales. At least theoretically -- we'll have to see how the data plays out and how the pandemic or endemic plays out.

Now, that said, they've got to obviously help patients, and inhibiting viruses is hard, if you just look at how long it took us to figure out -- us being the researchers -- to figure out how to inhibit hepatitis C. We were working on hepatitis C viral inhibitors for decades before Gilead and AbbVie came out with really strong inhibitors.

My understanding is that Pfizer's inhibitor was specifically designed for COVID-19 and Merck's wasn't; it was just a more general viral inhibitor. So, if I had to handicap it, I'd maybe give the slight advantage to Pfizer, but we'll have to wait and see the late-stage data before we'll know which one of these might be better than the other one, or maybe they're comparable.

Speights: Yeah. Brian, I agree with you. I think there could be a pretty sizable market here, especially because these are oral medications. It's different; we do have some antibody therapies that have been authorized by the FDA, or at least one -- Regeneron's, I guess. It's been authorized for post-exposure prophylaxis, but you have to go in and either get an infusion or subcutaneous injection, and from what I understand, those are pretty painful injections -- a couple in your stomach and one in each arm. But this is a pill.

In theory, if all goes well with these late-stage studies -- in theory, if they were authorized or approved by the FDA -- if you were exposed to COVID, then your doctor could write you a prescription and you just take a pill. That's a big advantage over having to go in and get an injection or an infusion.

Orelli: Yeah. Especially, if you're going to get an injection or infused, then you have to interact with the healthcare worker, and obviously, you can just go pick up your, you can get your pills mailed to you, so you aren't going to have to interact with anybody. There's that not potentially exposing healthcare workers to somebody who may be infected or is infected if we're talking about an actual treatment.

Speights: Right. Particularly, as we were discussing, if COVID-19 does become endemic, which seems like that's going to be the case, then it's going to be around for a long, long time. I think having oral pills to be able to take that -- if they're effective, that's the big if -- this could be a really big market for Pfizer and/or Merck here over the next however many years.

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