Rinvoq has long been touted as one of Abbvie’s get-out-of-jail-free cards once biosimilar competition to the group's bestseller, Humira, hits in 2023. However, Rinvoq’s saviour status depends on the Jak inhibitor’s ability to extend its approved indications beyond rheumatoid arthritis. So news that the US FDA is extending Rinvoq’s review in psoriatic arthritis by three months, and also has questions about another label extension into atopic dermatitis, did not play well; Abbvie shares slumped 6% in morning trading. The FDA has specifically asked for an update on Rinvoq's benefit-risk profile, which Leerink analysts suggested could be related to the 30mg dose used in psoriatic arthritis and atopic dermatitis; in rheumatoid arthritis a 15mg dose is approved. Abbvie had been hoping to challenge the market leader, Dupixent, in atopic dermatitis, and the signs had looked good, with Rinvoq comprehensively beating Dupixent head to head late last year. But success was tempered by toxicity issues and one reported death. While there are arguments that Rinvoq is one of the safest Jak inhibitors on the market, the class as whole has been dogged by safety concerns, and a recent scare from Xeljanz could have prompted more caution from the regulator.