Psoriasis drugs show promise

Targeted medications effective at clearing skin condition

Two experimental drugs given to patients with psoriasis can clear the skin condition’s characteristic thick, dry, red patches at unprecedented rates. The finding paves the way for the long-term clinical trials required for regulatory approval of the medications.

By toning down a key immune protein, the drugs wipe out many psoriasis plaques while showing few signs of side effects. Studies of the two drugs appear in the March 29 New England Journal of Medicine.

Provided major adverse effects don’t turn up in long-term tests, the two medications have a bright future, says Andrew Blauvelt, an immunologist and dermatologist at the Oregon Medical Research Center in Portland. “So far, these are looking like great drugs.”

Craig Leonardi, a dermatologist at the Saint Louis University School of Medicine, was part of both teams that tested the drugs, called ixekizumab and brodalumab. He and other researchers scored the severity of the patients’ psoriasis based on precise measurements of skin affected by the hallmark red plaques. A successful drug reduces a patient’s severity score by 75 percent.

All volunteers had had moderate to severe psoriasis affecting at least 10 percent of their bodies for six months. In one of the studies, Leonardi and his colleagues randomly assigned 142 patients to receive either ixekizumab or a placebo. In the other, 198 patients got brodalumab or placebo. In both studies, drugs and placebo were delivered as several injections spaced over 12 to 16 weeks, using various doses.

Both drugs reduced the psoriasis severity score by 75 percent in about four-fifths of patients getting a medium to high dose of either drug.

The drugs thwart the immune protein interleukin-17. In most people this protein plays a productive role, fending off bacterial and fungal infections, Blauvelt says. But people with psoriasis overproduce interleukin-17, which induces activation and growth of the outer-layer skin cells that make keratin. Only long-term testing, some of which is already under way, will establish that interleukin-17 activity can be suppressed by these new drugs indefinitely without risk of infection, Blauvelt says. 

Each study was funded by the drug’s manufacturer. Eli Lilly makes ixekizumab, and Amgen makes brodalumab.

Blauvelt says the new results compare favorably with previous early-stage studies of drugs that also target immune system proteins implicated in psoriasis. Some of these drugs have reached pharmacy shelves as etanercept (Enbrel), adalimumab (Humira) and ustekinumab (Stelara).

The last 10 years have seen “a very profound shift in the approach to treatment of psoriasis,” says dermatologist Kim Papp of Probity Medical Research, in Waterloo, Ontario, Canada, and coauthor of the brodalumab study.

And the targeted approach has vastly improved options for patients, Leonardi adds. “Fifteen to 20 years ago was still the therapeutic Stone Age [for psoriasis treatment] with the use of coal tar and ultraviolet light,” says Leonardi, who reports consulting for Amgen, Eli Lilly and other companies. He envisions that the two new drugs, if approved, will be lifelong injectable medications — just as insulin is for diabetes. “Chronic diseases require chronic therapies,” he says.

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