Psoriasis: Treating to Target, How Do You Get There?

LOS ANGELES, CA — Treat-to-target protocols for patients with moderate-to-severe psoriasis exist in the literature outside of the United States, but consensus efforts focused on treat-to-target in the United States are limited, according to Zelma Chiesa Fuxench, MD, MSCE.



Dr Zelma Chiesa Fuxench

“While they tell you what you should strive for, they don’t really tell you how to get there,” Fuxench, assistant professor of dermatology at the University of Pennsylvania, Philadelphia, said at the annual fall meeting of the Society of Dermatology Physician Assistants. “That’s partially done on purpose because experts who are studying this have come to the consensus that this is really a personal decision and discussion between each provider and their patient that needs to take into account each patient’s demographics, presence of comorbidities, prior treatment experience, and a thorough assessment of the risks and benefits of each treatment.”

Despite their limitations, treat-to-target goals are important, because they provide guidance on an end-goal for treatment and the opportunity to reevaluate the disease state and existing treatment regimen within a set time interval. “With currently available treatment options, achieving complete or almost complete skin clearance is a very realistic outcome for our patients with psoriasis, regardless of their baseline disease severity,” said Fuxench, who is a member of the American Academy of Dermatology’s Council on Science and Research. “We can get our patients to be clear.”

Common treat-to-target goals include a Psoriasis Area and Severity Index (PASI) score of less than 2, a Physician Global Assessment (PGA) of 0 to 1 (clear/almost clear), and body surface area (BSA) involvement of 1% or less. A consensus-building study involving psoriasis experts conducted by the National Psoriasis Foundation found that the most preferred instrument to define treatment targets was the BSA.

“Part of the reason for this is because if we’re being realistic, many of us will not be doing a PASI in the clinic; it just takes too much time,” Fuxench said. “But the BSA is something that we can assess rather quickly.” An acceptable response after initiating treatment is thought to be a BSA of less than 3% or at least a 75% improvement from baseline at 3 months after treatment initiation. The target response should be a BSA of less than 1% at 3 months after treatment initiation, while the target response during maintenance therapy should be a BSA of less than 1% at every 6-month assessment interval.

Clinicians can use the palm method, also known as the 1% hand test, to measure a patient’s BSA. The area from the distal wrist crease to the tips of the fingers (palm plus digits) equals about 1% of BSA, Fuxench said. If the number of plaques on the patient visually “fits” into the size of their palm, that translates to a BSA of about 1%. Having enough lesions adding up to three palms is considered mild psoriasis, while having enough lesions for three to 10 palms is considered severe disease.

Another measure of disease severity is the PGA. “This does not take into account the extent of the disease but only the quality of the lesions: how thick, red, and scaly they are, with higher numbers indicating more severe disease,” she said.

The PASI, a separate instrument, is a composite measure that considers both BSA and the lesion characteristics, with higher PASI scores indicating worse disease. “It’s important to become familiar with the PASI score even if you’re not going to be using it on a daily basis in clinic, because when you look at the data for clinical trials, they use PASI 75, PASI 90, or PASI 100 as their end measure,” Fuxench said.

Biologic Therapy

When it comes to choosing the correct biologic agent for patients, factors beyond efficacy and safety to consider include the presence or absence of certain comorbidities, as well as treatment preference such as timing of response and frequency of injections. Prior treatment experience is also important. “Has the patient been treated with biologics before?” she asked. “Insurance coverage is another factor. Whether you like it or not, this is our reality and often an important part of treatment decisions.”

Depression and Other Psychiatric Comorbidities

Fuxench noted that patients with psoriasis are at an increased risk for depression, anxiety, and suicidality. The data supporting this association include a large analysis of Danish administrative registries, which found that psoriasis was independently associated with the risk for depression. Between 1997 and 2016, 220,721 individuals with mild psoriasis were treated with topicals, 24,771 with moderate psoriasis were treated with systemic nonbiologic treatments, and 2,263 with severe psoriasis received biologic therapy. In adjusted models, the hazard ratios of depression were 1.19, 1.19, and 1.50 among those with mild, moderate, and severe psoriasis, respectively.

“I typically ask my patients ‘How are you feeling today?’ ” Fuxench said. ” ‘Do you have any depression?’ ‘Do you have any anxiety?’ ‘How is this related to your disease?’ ‘Is this impacting your quality of life?’ ” This opens up a conversation, she said, “because if I don’t ask those questions the patient often will not bring them forward and we don’t know if we need to be more aggressive with respect to treatment or refer to behavioral health.”

Society of Dermatology Physician Assistants (SDPA) 19th Annual Fall Dermatology Conference: Presented November 4, 2021.

Fuxench disclosed that she has served as a consultant for the Asthma and Allergy Foundation of America, the National Eczema Association, Pfizer, AbbVie, Incyte, and Beiersdorf. She has also received research grants from Regeneron, Sanofi, Tioga, Vanda, Menlo Therapeutics, Leo Pharma, and Eli Lilly.

Doug Brunk is a San Diego-based award-winning reporter for MDedge and Medscape, who began covering healthcare in 1991. He is the author of two books about the University of Kentucky Wildcats men’s basketball program.

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