Psoriasis Remission, Cure Definitions Vary Widely Across Studies

Deepak Balak

While the systemic treatment of psoriasis has improved significantly over the last two decades, there remains no consensus on or validated criteria for defining remission and cure. Notably, some researchers have abandoned the PASI50 criterion for stricter and narrower treatment goals, such as, PASI90, PASI ≤ 2, and body surface area (BSA) ≤ 1%.

A new systematic literature review, led by Deepak Balak of LangeLand Hospital in the Netherlands, has further identified and assessed various definitions of remission and cure of psoriasis as a means to inform and aid the development of consensus-based definitions. The review authors note that this “concept of psoriasis remission and cure as endpoint in clinical trials is becoming more relevant,” and thus stress the importance of their study in addressing such knowledge gaps.

The Systematic Literature Review

At the outset of their review, Balak and team used Medline/PubMed (National Library of Medicine), EMBASE (Embase.com/Elsevier), and The Cochrane Central Register of Controlled Trials (cochranelibrary.com) to identify studies discussing remission or cure of psoriasis.

They included observational and interventional studies that used consensus-based and non-consensus-based definitions of remission and/or cure in adults >18 years with plaque psoriasis.

“Additionally, we explored studies reporting consensus-derived psoriasis treatment goals and studies evaluating cut-off values of treatment goals for psoriasis remission and cure definitions,” they wrote.

Following screening and the application of inclusion/exclusion criteria (absence of definition, language restrictions, etc.), Balak’s team proceeded to evaluate a total of 136 articles. Of this total, 78% included a definition for psoriasis remission, and 5% provided a cure definition. The remaining 17% utilized consensus-derived psoriasis treatment goals or cut-off values for treatment goals.

They found that, of the studies reporting a definition for psoriasis remission, PASI75 was the most commonly used criterion (n = 16), followed by PASI90 (n = 10), and PASI100 (n = 10). Endpoints based on absolute PASI values were much less common.

Some studies (n = 7) used descriptive remission definitions, including “clearance” or related terms such as “clear” or “clearing” (n = 17). Other descriptions included “free of disease” and “no active skin lesions.

Body surface area (BSA) was used in 6 definitions, with the most commonly reported endpoints being BSA improvement > 90% (n = 3) and BSA improvement > 75% (n = 3).A small consensus-initiative defined drug-free remission as BSA of 0 with no therapy for ≥12 months.

The investigators noted few studies and definitions that specified time-frame, on/off treatment or other psoriasis-related disease domains.

“Most studies (n = 14) defined relapse by a PASI-increase >50% of baseline PASI. Other frequently reported definitions were BSA-increase >50% of baseline BSA (n = 7), need for treatment (n = 6), new lesions or exacerbation of existing lesions (n = 3), and increase in BSA ≥10% (n = 3),” the investigators wrote.

Partial remission was found in 12 studies and based on PASI (i.e. PASI improvements between PASI50 and PASI75 [n = 4] and > PASI75 [n = 3]).

Only 7 studies had defined psoriasis cure using same or similar endpoints to those commonly used to define remission – i.e. PASI100 (n = 1), PASI of 0 (n = 1), or 100% improvement on a 4-point physician overall assessment scale (n = 1).

“Our results indicate that a wide range of instruments and thresholds were used to define a state of psoriasis remission,” the investigators wrote. They indicated that 41 unique definitions were found among all evaluated studies.

“Due to the broad search strategy, this [systematic literature review] will inform potential future applications of a remission definitions across the breadth of both clinical research, interventional trials and clinical practice,” they concluded. “The benefit of a potential harmonized definition for psoriasis remission across clinical trials and clinical practice is that it would allow for seamless comparison of trial results vs. real-world evidence sources of data.”

The study, “Definitions of Remission in Psoriasis: A Systematic Literature Review from the National Psoriasis Foundation,” was published online in The Journal of the European Academy of Dermatology and Venereology.