Pfizer's solo Xeljanz can't match AbbVie's Humira in big RA head-to-head miss

Pfizer struggled early on to get RA pill Xeljanz to bring in the kind of sales it wanted—and a new head-to-head study against AbbVie behemoth Humira isn't going to help keep the momentum going as much as the New York drugmaker had hoped.

On Thursday, the company announced that Xeljanz, one in a new class of JAK inhibitors, had matched Humira when both drugs were paired with methotrexate. On its own, though, Xeljanz didn't measure up to the world’s best seller, missing the study’s primary endpoint of non-inferiority.

Pfizer, of course, had been hoping to show that Xeljanz could hang with the anti-TNF big guns—including Humira—as a monotherapy. The trial was the first to pit the JAK class against Humira.

Despite the result, Pfizer says it doesn’t regret trying. The phase 3b/4 study “is representative of the type of innovative and clinically meaningful trials that Pfizer Inflammation & Immunology believes are important to help advance patient care and the science of JAK inhibition,” said Michael Corbo, Pfizer’s chief development officer for the unit, said in a statement.

The results will make things more difficult for the pharma giant as it works to snap up share, though, especially with lower-cost biosimilars of Humira on their way.

After its 2012 launch, Xeljanz's ramp-up was slower than expected. One reason? Pfizer has had a tough time adding new indications. In October of 2015, the FDA shot Xeljanz down as a psoriasis treatment, and Pfizer has since said it would “reconsider” its investment in winning a nod in that crowded field. The company also nixed a couple of other Xeljanz development projects, in Crohn's disease and ankylosing spondylitis.

That’s not to say it’s been all bad news for the arthritis pill. Last summer, Pfizer announced that Xeljanz had beaten out placebo in a phase 3 ulcerative colitis maintenance study, posting a significantly higher proportion of patients in remission at week 52.

And despite the new-indication frustration, the company has managed to swell Xeljanz sales considerably over last couple years. From $113 million in 2013, its first full year on the market, the drug grew to $927 million worldwide in 2016. For the fourth quarter alone, Xeljanz kicked in $278 million to Pfizer’s top line, an increase of 62% over the year-ago quarter. If that pace continues in 2017, it would break the blockbuster barrier this year.

The question is whether Xeljanz can keep that up after Humira's biosims hit the market. AbbVie itself has been scrambling to get ready for that lower-cost competition, of course, but analysts expect the new rivals to take a toll on other brands in the field as well.