Innovaderm’s management of more than 160 studies has yielded valuable perspectives on the most frequently employed measures across diverse indications. Come join us as we disclose the top 3 clinical outcome assessments (COA) in psoriasis trials, providing insights into the most used instruments for evaluating treatment efficacy in psoriasis.
1. Body Surface Area (BSA)
The evaluation of the overall BSA affected by psoriasis is ranging from 0% to 100%. The palmar surface of one hand, including the fingers, represents 1% of the total BSA. The investigator then calculates the BSA involvement by counting the number of handprints with psoriatic lesions across the patient’s body.
2. Psoriasis Area Severity Index (PASI)
The PASI is a quantitative rating score for measuring the severity of psoriasis based on area coverage and plaque appearance. The calculation of the PASI score involves the assessment of 4 main body areas: head, trunk, upper extremities, and lower extremities, representing 10%, 30%, 20%, and 40% of the total body area, respectively. The numerical value assigned to the psoriatic involvement in these areas ranges from 0 (no involvement) to 6 (90%–100% involvement). To evaluate the severity of the psoriatic lesions, 3 target symptoms, namely erythema (E), induration/infiltration (I), and desquamation (D) are assessed using a scale from 0 to 4, where 0 means no symptoms and 4 represents very marked symptoms. The sum of the severity ratings for the 3 target symptoms in a given body region is multiplied by the numerical value corresponding to the degree of psoriatic involvement in that body region and the proportion of that body region to the whole body. The values obtained for each body region are then summed to obtain the PASI score.
3. Physician’s Global Assessment (PGA)
The PGA is a global assessment of the current state of psoriasis. It is a 5-point scale, with scores ranging from 0 (clear) to 4 (severe) that assesses the severity of psoriasis, excluding lesions on palms and soles. The scoring categories are as follows: 0 for clear, 1 for almost clear, 2 for mild, 3 for moderate and 4 for severe. Clear is defined as having no signs of psoriasis, with post-inflammatory hyperpigmentation possibly present, while severe indicates severe thickening with hard edges, bright to deep dark red coloration, and severe/coarse scaling covering almost all or all lesions.
Table 1. Key Psoriasis Top 3 COA Characteristics
| Instrument | Global Assessment | ClinRo | PRO | Validated in Adults | Validated in Children/
Adolescent |
License Requirement | Reference |
| BSA | ✔ | ✔ | ✔ | No | Ramsay 1991 | ||
| PASI | ✔ | ✔ | ✔ | No | Fredriksson 1978 | ||
| PGA | ✔ | ✔ | ✔ | No | Langley 2015 |
Conclusion
In sum, the article discusses three key COAs: the BSA, the PASI, and the PGA. These instruments provide a thorough and measurable method for evaluating the severity and reach of psoriasis, thus being integral to the success of clinical trials. The application of these standardized tools ensures uniform measurement and comparison across distinct studies, thereby boosting the credibility and accuracy of research outcomes. Consequently, these assessment tools are indispensable not only for the advancement of scientific knowledge but also for improving patient care and outcomes in psoriasis.
About the author
A seasoned scientist and medical writing expert, Teresa is dedicated to fostering scientific engagement and enhancing the strategic value of medical affairs and innovation in clinical trials. She seamlessly navigates her roles with a decade-long background in preclinical research across various therapeutic areas.
