Eli Lilly’s Taltz is already up against Novartis’ immunology blockbuster Cosentyx in psoriasis and psoriatic arthritis. Now, Lilly looks poised to challenge the Swiss drugmaker in a third indication, too.

Thursday, Lilly said Taltz had significantly improved the signs and symptoms of ankylosing spondylitis (AS) in a phase 3 study, nailing the trial’s primary goal and its major secondary endpoints, too. And as the drugmaker was quick to point out, it defined success by the proportion of patients who reached a score of 40 on the Assessment of Spondyloarthritis International Society scale by the 16-week mark; the "traditionally used endpoint" is ASAS20, a lower bar.

It’s not the first positive AS data Lilly has touted for Taltz; back in February, the company trumpeted a win in a separate phase 3 trial. This time, though, the data focused on tough-to-treat patients who either hadn’t responded well to one or two anti-TNF drugs or couldn't tolerate them.

"These positive results, in combination with previous results from the phase 3 COAST-V study, provide further support for Taltz as a potential treatment option for patients with AS," Dr. Lotus Mallbris, VP of immunology development for Lilly, said in a statement.

The pharma giant plans to submit the data to U.S. regulators later this year. Details of the study win will roll out at a medical meeting later this year.

If Taltz can pick up an AS nod, it’ll open up a third arena for the Taltz-Cosentyx battle. The Lilly drug won its psoriasis go-ahead back in March 2016, just over a year after Cosentyx did. And Lilly’s psoriatic arthritis (PsA) approval, granted this past December, came nearly two years after Cosentyx picked up simultaneous nods in PsA and AS.

Still, despite Cosentyx’s big head starts, Taltz is in a good position, Lilly’s execs say, pointing to sizable market opportunities. The PsA market, "we think, will be very large and we think we’re competitive," Christi Shaw, president of Lilly Bio-Medicines, said on the company’s fourth-quarter earnings call in January.

And while other like therapies—in-class IL-17 rival Siliq from Valeant and a pair of IL-23 drugs, Johnson & Johnson’s Tremfya and Sun Pharma’s Ilumya—are snapping up psoriasis share, they haven’t yet made it into the PsA or AS fields.