Topical steroids and moisturizer are the mainstay treatments for eczema. However, steroids have a lot of unwanted side effects and moisturizers alone can’t treat most eczema patients. The topical options to treat eczema are limited. Outside of steroids, eczema patients can also use the topical calcineurin inhibitors such as tacrolimus and pimecrolimus. The FDA is recently approved crisaborole as a treatment for mild to moderate eczema. This is the latest topical medication for eczema approved in the past 15 years.
Crisaborole for Eczema
Most people who suffer from eczema have mild to moderate disease.
However, even mild disease can result in significant itching and decreased quality of life. Crisaborole is intended to treat mild to moderate eczema.
Crisaborole Over Topical Steroids
Topical steroids can decrease inflammation, but they have many unintended consequences. Some of the side effects of topical steroids are skin atrophy, striae, and systemic effects when they get into the bloodstream.Crisaborole does not have these unwanted side effects.
How does crisaborole work?
Crisaborole is a phosphodiesterase-4 inhibitor (PDE4). (1) This means that crisaborole is able to block the action of PDE4.
PDE-4 is a molecule of inflammation in the body. It directs other parts of your immune system to make even more inflammatory molecules. Patients with eczema have increased levels of PDE4 in their skin.The cool thing about is crisaborole is that it is a very small molecule. It obeys the 500-dalton rule of skin penetration. Like I’ve written about elsewhere, 500 daltons is the upper limit size for a molecule to be able to penetrate the skin and have an effect. Crisaborole weighs 251 daltons.
Research and Evidence Behind Crisaborole
Two clinical trials comparing crisaborole ointment to placebo have been published.
A total of 1,522 patients were enrolled in these studies. Of the total enrolled, 1,016 received crisaborole and 506 received placebo ointment.
They included patients greater than 2 years of age with mild to moderate eczema. The patients enrolled could not use biologic therapies or systemic steroids for a month before starting the study. The studies lasted for 28 days.
The main outcome of the study was the number of patients with clear or almost clear skin at the end of the 28 days. The investigators also measured itching severity.
Results of Clinical Trials
The studies found that for the patients treated with crisaborole, 51% and 48% of patients in each study had clear or almost clear skin. For the placebo group, only 40% and 29% of patients achieved clear or almost clear skin.
Although these numbers don’t seem to show an obvious improvement with crisaborole, the use of a placebo ointment alone has been shown to improve eczema in many studies. This is because eczema is treated with moisturizers and emollients. Any use of a topical ointment will improve eczema. These studies were able to show that by adding crisaborole to the ointment, the eczema was treated better and faster.
Common Side Effects with Crisaborole
The most common adverse effect with crisaborole use was pain at the application site (like burning and stinging) seen in 4.4% of patients. The studies found very low rates of side effects and no serious adverse events occurred.
Crisaborole is absorbed by the skin and can thus have systemic effects. The most common side effects of oral PDE4 inhibitors are gastrointestinal complaints. However, the body breaks down crisaborole rapidly. The inactive breakdown products have no biological activity.
This study found that 2.7% of patients treated with crisaborole and 2.4% of placebo patients had gastrointestinal side effects. These rates are very similar and were likely not due to the drug.
Crisaborole is a new drug, therefore, long-term safety data isn’t available yet. Based on studies done on rodents, crisaborole does not cause cancer.
When will crisaborole be available to the general public?
The FDA completed their review of the data from the clinical trials on crisaborole and approved the drug in December of 2016. Crisabarole is now available to be prescribed by doctors.
What are your thoughts on crisaborole for eczema?
- Paller AS, Tom WL, Lebwohl MG, et al. Efficacy and safety of crisaborole ointment, a novel, nonsteroidal phosphodiesterase 4 (PDE4) inhibitor for the topical treatment of atopic dermatitis (AD) in children and adults. J Am Acad Dermatol. 2016;75(3):494-503.e4.
- Drugs.com. Anacor Pharmaceuticals Announces FDA Acceptance of NDA for Crisaborole Topical Ointment, 2% for the Treatment of Mild-to-Moderate