The U.S. Food and Drug Administration approved the drug guselkumab (tremfya) to treat moderate-to-severe plaque psoriasis, announced Janssen Biotech, part of Johnson & Johnson, in a release. The drug is “the first and only approved biologic therapy that selectively blocks only IL (interleukin)-23, a cytokine that plays a key role in plaque psoriasis,” the company says.

Plaque psoriasis — the most common of five kinds of the disease — causes buildups of silvery-white dead skin cells (called plaques) upon red, patches. “The plaques might be itchy or painful, and there may be few or many,” according to the Mayo Clinic. “They can occur anywhere on your body, including your genitals and the soft tissue inside your mouth.”

About 2 to 3 percent of the population has psoriasis, according to National Psoriasis Foundation. Children with one parent who has psoriasis have a 10 percent chance of contracting the disease, and that number increases to 50 percent if both parents have psoriasis, according to the foundation.

In tests, seven out of 10 patients who took the newly-approved drug experienced improvements in their skin of at least 90 percent, and 80 percent saw cleared or almost cleared skin, Janssen reported. And by week 48, that percentage went from 70 to 75, whose skin cleared up by at least 90 percent.

The drug “is administered as a 100 mg subcutaneous injection every eight weeks, following two starter doses at weeks 0 and 4,” the release states. It adds that patients receiving the drug in clinical studies “experienced significant improvement in skin clearance and greater improvement in symptoms of plaque psoriasis including itch, pain, stinging, burning and skin tightness when compared with placebo at week 16.”

The approved drug represents a “significant milestone in the treatment of moderate to severe plaque psoriasis,” noted dermatologist Andrew Blauvelt, president of Oregon Medical Research Center and a study investigator, in the release. “We continue to make progress in understanding the science of psoriasis and the important role IL-23 plays in the pathogenesis of this disease.”

[Learn more about psoriasis treatment.]

The release also quotes a patient, Patti Janick, who participated in the clinical trial. “Living with plaque psoriasis is challenging, especially the constant pain, itching and burning,” Janick said. “I am encouraged by the results I’ve experienced with [the drug] and the possibility it offers others living with plaque psoriasis to find similar relief and clearer skin.”

The newly-approved drug outperforms Humira in several key areas, according to the Janssen release, and the company says it will work closely with providers, payers, and pharmacy benefit managers to ensure the drug is accessible and affordable and “that the cost for payers is competitive with currently available biologic therapies for psoriasis.” There are also applications under review in the European Union, Japan, and other countries.

Side effects may be serious, including infections, the release states, and the drug can lower the immune system’s ability to fight infections. The most common side effects include “upper respiratory infections, headache, injection site reactions, joint pain (arthralgia), diarrhea, stomach flu (gastroenteritis), fungal skin infections, and herpes simplex infections.”

Remember to discuss any questions or concerns with your doctor.