FDA-approved arthritis drug may work in new ways to fight itch.
The roots of chronic itching have long remained a mystery. Meanwhile, those with the condition suffer from an unrelenting and sometimes debilitating urge to scratch. Now, new research at Washington University School of Medicine in St. Louis has identified immune signaling molecules that are essential for activating neurons in the skin to cause chronic itching.
In a small study, the researchers also discovered that people with a type of itch from an unknown cause, a condition called chronic idiopathic pruritus, improve when given tofacitinib (Xeljanz), a drug approved for rheumatoid arthritis. Earlier attempts to treat their itching with other anti-inflammatory drugs had not been successful, but within one month of taking tofacitinib, all five patients in the study experienced marked relief from severe itching.
The findings are published Sept. 8 in the journal Cell.
“These patients often itch day and night, and for some of them, the urge to scratch never goes away,” said senior investigator Brian S. Kim, MD, an assistant professor of medicine and co-director of Washington University’s Center for the Study of Itch. “Although this was a small study, the patients taking tofacitinib experienced dramatic improvements in terms of their itch, allowing them to sleep, stop scratching and return to living more productive lives. Obviously, we’ll need to do a larger study, but the early results are very encouraging.”
The findings also explain why an earlier study found that itching dissipates dramatically in eczema patients treated with the new drug dupilumab (Dupixent). Eczema patients have itchy, scaly rashes. The Washington University researchers found that drugs such as tofacitinib and dupilumab work so well, where many other drugs have failed, because they act directly on the nerves rather than only on the immune system.