AstraZeneca (NASDAQ:AZN) and its partner Sanofi (NASDAQ:SNY) recently announced promising results from a late-stage study of nirsevimab in preventing respiratory syncytial virus (RSV) in infants. In this Motley Fool Live video recorded on April 28, 2021, Motley Fool contributors Keith Speights and Brian Orelli discuss whether or not the two companies can win big with this experimental RSV therapy.

Keith Speights: Let's stay on AstraZeneca. we've been talking about some bad news that the drugmaker has experienced. But AstraZeneca actually had some good news this week.

The company along with its partner, Sanofi, recently, just earlier this week, announced good news on another front. The companies reported positive results from a phase III study of Nirsevimab in protecting against respiratory syncytial virus RSV in infants. What do you make up these RSV results, Brian?

Brian Orelli: I mean, there's not much to make because as large drugmakers are apt to do, the companies held back the details for a medical meeting. For now, all we know is that the treatments reduce infections compared to placebo, but we don't know by how much. We know that it was presumably it was statistically significant, so it seem like it passed the clinical trial with those.

The companies are also testing the drug against Synagis, with data expected in the second half of 2021. Synagis is the current standard of care which is sold by Swedish Orphan Biovitrum.

Speights: You pronounced that better than I would have. [laughs]

Orelli: I think they go by Sobi.

Speights: Yeah, [laughs] there we go.

Orelli: I just want to go with Sobi. That's probably better.

Speights: Yeah. Brian, I think this -- you're right. They haven't really released much detail at all from these results. But assuming everything is positive is what they are alluding to so far, this could be a good step for AstraZeneca and Sanofi.

I was looking at some of the CDC statistics about RSV, and the CDC reports that there were 2.1 million outpatient visits among kids younger than five years old for RSV. I think this data is from maybe 2019, something like that.

I mean, we're talking about a lot of outpatient visits for kids with RSV, and 58,000 hospital visits or hospitalizations among children younger than age 5. So this is a big deal in the younger kids' arena.

It's also a big deal for senior adults. The CDC says that they were 177,000 hospitalizations among adults older than 65 years old with 14,000 deaths in the senior adult population from RSV.

There's opportunities, not just with the younger kids, but also with senior adult. So this could be a long-term potential growth story for AstraZeneca here.

Orelli: Yeah. I don't know how much of an opportunity. It's not a vaccine or it's a passive vaccine where you're putting in the antibody that binds to RSV, which means it's not going to last nearly as long as an actual vaccine would, which would protect you theoretically through your entire life, but certainly years and years.

I think that that's the downside of this, it's a passive vaccine, is that may only be given to prenatal infants or people who will be most susceptible to dying from RSV versus ones that are only have to go to the regular doctor. I don't necessarily see this as being a preventative, doctors giving this as a preventative for everybody just in case there's a small number of barely healthy children might get RSV and might have to go see the doctor.

I should point out, some of them are going to go in the hospital. I think the rate is low enough of death in generally healthy people, but I'm not sure that this will be given to generally healthy children and older adults.

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