Autoimmune diseases, such as rheumatoid arthritis, atopic dermatitis, and psoriatic arthritis, offer a multibillion-dollar opportunity for JAK inhibitors. In this video from Motley Fool Live, recorded on March 22, Fool.com contributors Brian Orelli and Keith Speights discuss the JAK inhibitors under development and which ones might be the safest bet given the Food and Drug Administration's crackdown on the drug class.

Brian Orelli: Then there are quite a few other companies that are developing JAK inhibitors that are either approved or going late-stage -- going through the first indication or they are approved and going for additional indications. Any thoughts on other companies developing JAK inhibitors, and timing and prospects?

Keith Speights: There are actually quite a few. We already mentioned Gilead Sciences (GILD +2.90%) and Galapagos (GLPG +4.89%). While they received the FDA rejection for filgotinib in the U.S., they did win European approval for the drug and treating rheumatoid arthritis last year. They're hoping to win another European approval for treating ulcerative colitis in the second half of 2021. Europe seems, I guess, the best way to put us a little more lax toward some of these safety issues than the FDA is, so we will see. Maybe Gilead and Galapagos will win another indication there for filgotinib.

Then Pfizer (PFE +3.63%), we already talked about Xeljanz. Well, Pfizer's hoping to pick up yet another FDA approval for Xeljanz and another indication, ankylosing spondylitis. They hope to win that approval in the second quarter of this year. Pfizer has a new drug on another JAK inhibitor called abrocitinib. They're hoping to pick up an approval from the FDA by late April. I think April 27 is the PDUFA date there in treating atopic dermatitis. And then they also hope to win European approval in the second half of this year. So Pfizer has the second JAK inhibitor waiting in the wings.

We mentioned Lilly's (LLY +4.46%) Olumiant, the FDA has also scheduled, making a decision on it in treating atopic dermatitis in the second quarter of this year.

Last but not least, Incyte (INCY +4.05%) also has a JAK inhibitor that's been on the market for quite a while now, Jakafi, and the FDA is scheduled to make a decision on a topical application of Jakafi in June. Lots of activity among these JAK inhibitors.

Orelli: I really think that Incyte one is probably the safest bet because it's a topical application. I think the FDA is going to be a lot less worried -- so the problem here, the way JAK inhibitors work is they're basically be dampening the immune system. That's why it works for autoimmune diseases, like the ones we've been talking about. But by using it as a topical, it's less likely to get into blood and have systematic problems compared to taking it orally.