Therapies that interfere with messengers used by DNA to create proteins (RNA) finally made the leap from clinical-stage hype to commercial-stage launch when the FDA approved Alnylam's (NASDAQ:ALNY) RNAi for hereditary transthyretin-mediated amyloidosis (hATTR) in August.

In this clip from The Motley Fool's Industry Focus: Healthcare, analyst Shannon Jones and Todd Campbell discuss the importance of this revolutionary new treatment approach and the commercial opportunity for Alnylam's Onpattro in 2019.

A full transcript follows the video.

This video was recorded on Dec. 12, 2018.

Shannon Jones: Our fifth top story is centered around a first here in biopharma land. 2018 was a first year for many different therapeutic assets and disease classes. One in particular is a technology called RNAi, RNA interference. It's basically a technique to silence troublesome genes. Todd, this is also a Nobel Prize-winning therapy. A lot of expectations on the floor for the company behind this drug.

Todd Campbell: Yeah. The whole concept of interfering with these messenger RNA that basically allows for a gene to produce a protein, that is not a new concept. It's been around a long time. One of our fellow Fools, Brian Orelli, had a great article way back in 2007 -- 11 years ago -- about the promise of RNAi. And in 2018, we finally got the first approval of a drug that works this way, and that was the FDA OK of Alnylam's Onpattro.

Jones: With Onpattro, it took Alnylam 16 years to actually successfully launch this drug. And it's got an eye-popping price tag, Todd. We're looking at $450,000 for a disease class that is not that huge. Globally, we're looking at maybe 50,000 patients. Here in the U.S., it's even smaller than that. What do you have to say about the runway for this particular drug here?

Campbell: It's great that we've been validated now on this approach, of this option that's available for these patients. The disease we're talking about, hereditary transthyretin and mediated amyloidosis -- ATTR is what we'll call it -- it's a debilitating and often fatal genetic disease. So, it's great that this has been approved. It's a relatively small addressable market, as you mentioned. Actually, the second RNAi was approved by the FDA in October when they approved Ionis and Akcea's Tegsedi. So, there's actually two similarly working RNAi drugs that are now on the market targeting this one approach. That, of course, means that they're going to have to divide the market opportunity between the two of them. It'll be very interesting to see whether or not one is a winner or one is a loser in 2019. Keep an eye on both of them.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.