AAD-NPF Guidelines and Treatment of Plaque Psoriasis
OCTOBER 02, 2019
Mark Lebwohl, MD: The American Academy of Dermatology [AAD] and the National Psoriasis Foundation [NPF] have issued guidelines on the treatment of psoriasis. The guidelines are actually fairly loose. They leave a lot up to the prescribing physician. But what they do say is that, certainly, if you have more than 10% of your body surface area affected, treatment with a systemic therapy is more than justified, either systemic therapy or phototherapy. If you have a percentage of body surface area that’s under 10%, you can try to get by with topical therapy. But again, even in those patients with more limited disease, if the disease affects the face, or there is severe involvement of the scalp, or the palms and soles that interferes with your daily activities and walking, it can still be severe. In those circumstances, treatment with a systemic therapy is often justified.
There isn’t a single standard of care first-line therapy in psoriasis. We have, fortunately, a lot of choices that are tapered to the particular patient’s needs and circumstances. If a patient has very limited disease on the elbows and knees, for example, we would normally first try topical therapy. If that didn’t work, we have many additional options. We can use combinations of different topicals. We can use something called the excimer laser, which is a localized form of phototherapy; or we can treat the patient with intralesional injections of steroids. All of those are acceptable early therapies for limited disease.
If a patient has more severe disease that is more extensive, involving more than 10% of body surface area, the use of topical therapy is impractical. For those patients, we then have the options of either phototherapy, pills, or injectable medications called biologics.
Phototherapy is quite a commitment. It involves going to light treatments usually 3 times a week. While home phototherapy is available, not everyone has the room for it, and some of the home units don’t work as well as the units that are offered in a phototherapy center. So patients often have to travel to a center 3 times a week for months. It’s a big time commitment, and most patients do not have the ability to take that time out of their life to go for treatment 3 times a week. But it is a viable option for some patients.
We have several pill therapies available for the treatment of psoriasis. One that is approved is cyclosporine. It is not good for long-term use, and the guidelines say it shouldn’t be used for more than a year total. After a year, and certainly after 2 years, 100% of patients have evidence of kidney damage from cyclosporine. It also has a whole host of other adverse effects. Methotrexate used to be the most common treatment used for psoriasis, before we had biologic therapies. It is associated with a number of adverse effects, primarily bone marrow toxicity and liver toxicity, which have limited its use.
Acitretin is an oral therapy that also has been available for decades. It is associated with severe birth defects, but the reason it’s probably not used more often is because it’s not that effective as monotherapy and it has a lot of mucocutaneous effects that are unacceptable to patients. They lose hair, their skin develops a sticky feeling. So it’s not used very widely. Although occasionally in combination with other therapies like phototherapy, it is very useful in low doses, which minimize the mucocutaneous adverse effects.
The fourth oral medication we have is called apremilast. Its main adverse effects are diarrhea and weight loss. Now, weight loss is often liked by our psoriasis patients since many are obese. It is modestly effective, but it is quite safe, and that’s where it gets a lot of use. Clinicians are not worried about prescribing it. Patients are not worried about taking it. The mechanism by which it acts is phosphodiesterase inhibition, and things like caffeine are phosphodiesterase inhibitors. So it’s not a dangerous treatment, and it is modestly effective.
There are some more effective medications on the horizon. They’re either called Janus kinase inhibitors, or there is one that looks like it’s closest to being approved for psoriasis, a TYK2 inhibitor, a tyrosine kinase 2 inhibitor, and hopefully we’ll have that available. It is more effective than apremilast. It probably is a little more immunosuppressive, but so far the phase 2 data from its studies appear to be quite benign. It does not seem to have any serious adverse effects, so far, in a limited number of patients.
Transcript edited for clarity.