The Food and Drug Administration (FDA) has recently approved dupilumab (Dupixent) injection for a new indication: treatment of prurigo nodularis, a rare skin disease. Prurigo nodularis produces itchy nodules and affects approximately 87,000 adults a year. The itching can be severe enough to lead to bleeding from scratching. Previously, dupilumab was approved for the treatment of atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyposis, and eosinophilic esophagitis.

Dupilumab is a human monoclonal antibody that inhibits interleukin-4 and interleukin-13 by binding to the interleukin-4 receptor [alpha] subunit shared by interleukin-4 and interleukin-13 receptor complexes. Binding to this receptor site decreases inflammation, an important component in the pathogenesis of prurigo nodularis.

The drug's effectiveness for prurigo nodularis was determined in two 24-week randomized, double-blind, placebo-controlled, multicenter, parallel-group trials in a total of 311 adults. Subjects were asked to rate the intensity of the worst itching experienced over the past 24 hours on a 10-point scale (0 = no itching, 10 = worst itching imaginable) and the clinician evaluated the number of nodules produced (0 = clear, 4 = severe). Efficacy was assessed by the proportion of subjects who reported improvement in itching by four or more points and/or were found to have a smaller number of nodules. Both efficacy criteria were met in the first trial by 38.7% of those receiving dupilumab compared with 9.2% of those receiving placebo and in the second trial by 32.1% of those receiving dupilumab compared with 8.5% of those receiving placebo.

Warnings and precautions for dupilumab are similar to those listed previously on the dupilumab labeling for other indications (hypersensitivity, conjunctivitis and keratitis, eosinophilic conditions, and arthralgia). The most common adverse effects when dupilumab was used to treat prurigo nodularis were nasopharyngitis, conjunctivitis, herpes infection, dizziness, myalgia, and diarrhea. Allergic reactions are also possible and can be severe, including anaphylaxis; patients should know to contact their prescriber immediately if these occur and to contact emergency medical services if they experience difficulty breathing.

Dupilumab comes in prefilled syringes and is administered subcutaneously. Nurses should teach patients how to administer the drug and how to dispose of the used syringe. The syringe should not be disposed of in household trash. Either an FDA-cleared sharps disposal or a household container made of heavy-duty plastic, such as a laundry detergent bottle, can be used. The container must have a tight-fitting lid and be puncture and leak resistant. It should be labeled to warn of hazardous waste inside. The patient should follow local or state laws regarding disposing of needles and syringes. Information on medical sharps disposal for each state is available at https://safeneedledisposal.org.

For complete prescribing information for dupilumab, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2022/761055s044lbl.pdf.