AstraZeneca (LON:AZN) has won FDA approval for Saphnelo (anifrolumab-fnia) to treat moderate to severe systemic lupus erythematosus (SLE) in adults.

The drug is the first treatment for SLE to win FDA approval in more than one decade.

Saphnelo targets the type I interferon (IFN) pathway, which plays a role in the pathophysiology of lupus. Researchers have linked elevated levels of type I IFN signaling with increased disease activity and severity.

“We have known since the 1970s that interferons were involved with lupus,” said Dr. George Tsokos, a member of the Lupus Foundation of America Medical-Scientific Advisory Council, in a statement. “With the approval of Saphnelo, we now have one more drug that allows us to translate valuable research knowledge into clinical practice with multiple benefits for our patients with lupus.”

In approving the drug, FDA considered data from two TULIP Phase 3 trials and the MUSE Phase 2 trial.

Across those studies, a higher number of patients taking SAPHNELO saw improvements in overall disease severity and were more likely to taper oral corticosteroid use than placebo recipients.

AstraZeneca focused on reducing steroid use when possible in the clinical trial, said Dr. Joan Merrill, an independent researcher involved in the TULIP Phase 3 trials. “Tapering steroids enabled the efficacy signal to shine through for [anifrolumab] and for some drugs developed around the same time,” Merrill told Drug Discovery & Development in June.

Merrill is the director of clinical projects, arthritis and clinical immunology program at the Oklahoma Medical Research Foundation.

[Related: How lupus clinical trials are evolving]

The FDA notes that it does not recommend the drug for severe active lupus nephritis or severe active central nervous system lupus. There is currently no clinical trial evidence for that patient subset.

SLE is the most common form of lupus.

Regulatory authorities in the EU and Japan are reviewing the drug.

AstraZeneca is planning on running subsequent clinical trials involving the drug in patients with lupus nephritis, cutaneous lupus erythematosus and myositis.