The International Dermatology Outcome Measures (IDEOM) initiative is a nonprofit organization dedicated to enhancing clinical care and research in dermatology by developing evidence-based, patient-centered outcome measures. At the 2019 annual meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), the IDEOM psoriasis working group presented an overview of its selected deliverables and discussed its efforts to agree on meaningful, valid, and feasible outcome measures for quality measurement in psoriasis. The psoriatic arthritis (PsA) workgroup focused on the measurement of PsA symptoms in psoriasis clinical trials, and the measurement of nonspecific musculoskeletal symptoms among patients with psoriasis in psoriasis longitudinal clinical trials and cohort studies.

The 2019 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) was held in Paris, France, and was attended by rheumatologists, dermatologists, representatives of biopharmaceutical companies, and patients. As in previous years, GRAPPA members held a symposium for trainees to discuss their research in psoriatic disease with experts in the field. Other subjects featured during the annual meeting included a composites workshop to review continuous composite measures; the GRAPPA-Collaborative Research Network's third annual meeting; the need for a precision medicine approach to the treatment of psoriatic disease; updates from working groups in International Dermatology Outcome Measures and Outcome Measures in Rheumatology; a debate on the effectiveness of methotrexate in the treatment of psoriatic arthritis (PsA); updating recommendations for optimal treatment approaches for patients with PsA; an update on GRAPPA's research and educational projects; and the GRAPPA ultrasound (US) working group's goal to optimize the evaluation of enthesitis in patients with PsA using US through the development of a diagnostic US enthesitis tool. In this Prologue, we introduce the papers that summarize that meeting.

Improving the assessment of psoriatic arthritis (PsA) is a key purpose of the Group for Research and Assessment of Psoriasis and PsA (GRAPPA). Herein, we report the proceedings of the GRAPPA composites workshop at the 2019 GRAPPA annual meeting and the membership's recommended next steps. A review of continuous composite measures was conducted in an introductory workshop, followed by 10 breakout group sessions and a final plenary session for feedback and voting. Participants included 154 members: 87 rheumatologists, 18 dermatologists, 2 rheumatologist/dermatologists, 12 patient research partners, 14 academics, 1 methodologist, and 20 industry members. Of voting members, 88.8% agreed a need exists for a continuous composite measure for routine practice, but only 62% were currently using a composite measure. Of these, 27% were using the 28-joint count Disease Activity Score (DAS), which is not a PsA-specific measure; 20% were using a PsA-specific measure such as PsA DAS (PASDAS), Composite Psoriatic Disease Activity Index (CPDAI), or Disease Activity Index for PsA (DAPSA). Members agreed that the existing measures were not feasible in their current forms (CPDAI 83%, PASDAS 82%, and DAPSA 47%) and that modification should be tested. The majority (76%) agreed that disease effect should be measured separately from disease activity. The GRAPPA membership supports the need for a continuous composite measure of disease activity for use in routine clinical care, the separate measurement of disease effect and activity, and the testing of modifications to candidate instruments rather than the development of new measures.

The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA)-Outcome Measures in Rheumatology (OMERACT) Psoriatic Arthritis (PsA) working group provided updates at the 2019 GRAPPA annual meeting on its work toward developing a core outcome set for PsA. The working group prioritized 4 domains, including musculoskeletal disease activity (enthesitis and dactylitis), fatigue, physical function, and structural damage. In this report, the working group summarizes its progress in standardizing the core outcome set for these 4 domains.

The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) held a trainees symposium at its 2019 annual meeting in Paris, France. Rheumatology and dermatology trainees engaged in psoriasis or psoriatic arthritis research presented their work. This report briefly reviews 5 oral presentations and 19 posters presented at the meeting.

At the 2019 annual meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA), members received updates on several ongoing efforts. Among them were updates on research, including the trainee symposium, pilot research grants, and the Collaborative Research Network; GRAPPA's patient research partners; education, including the slide collection; treatment recommendations; and additional work related to advancing the understanding of disease aspects, including the Outcome Measures in Rheumatology (OMERACT)-GRAPPA outcome measure, axial involvement, and ultrasound enthesitis projects; as well as the early psoriatic disease systematic literature review and magnetic resonance imaging.

Current management approaches for the treatment of psoriasis and psoriatic arthritis (PsA) are imprecise and depend largely on clinical assessment. A more precise approach, which takes into account an individual patient's variations in genes, proteins, environment, and lifestyle, is beginning to receive attention with the most advanced progress seen in the treatment of cancer. Herein, the methodological approaches required for this precision medicine approach to be adopted in psoriatic disease, as well as their advantages, are reviewed. In addition, advances that are being made to address areas of unmet need in PsA, notably the use of proteomic approaches, are presented with suggestions that combine genetic and protein data (proteogenomics). Finally, progress that is being made in 2 large-scale, multipartner studies focused on the development of a precision medicine approach to the treatment of skin psoriasis is presented and discussed.

Enthesitis is a key feature in psoriatic arthritis (PsA) and may be the initial site of musculoskeletal inflammation in patients with PsA. Ultrasound (US) optimizes the detection of enthesitis, but the lack of a validated sonographic enthesitis scoring system for PsA limits the ability to conduct US-based studies of approaches to improve the early diagnosis of PsA. Creating a sonographic enthesitis scoring system that reliably identifies PsA at early stages is an important step in optimizing early diagnosis and encouraging timely interventions that will ultimately improve longterm outcomes for patients with PsA. The Group for Research and Assessment of Psoriasis and PsA (GRAPPA) US working group has set a goal of improving the evaluation of enthesitis in patients with PsA by using US through the development of a Diagnostic Ultrasound Enthesitis Tool (DUET). This article summarizes the proposed DUET study design and methodology as discussed during the 2019 GRAPPA annual meeting in Paris, France.

Methotrexate (MTX) is the most commonly prescribed first-line therapy in psoriatic arthritis (PsA) internationally and is also commonly used in the treatment of psoriasis. However, data supporting its use in PsA are limited and significant toxicities can occur. This article summarizes a debate at the 2019 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) annual meeting that focused on the use of MTX in psoriasis and PsA. Four clinicians and 1 patient research partner presented clinical study data and the patient experience summarizing the efficacy, tolerability, and toxicity of MTX for both skin and musculoskeletal manifestations. A survey of attending GRAPPA members collected data on current and planned future use of MTX across the world.

At the 2019 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis-Collaborative Research Network annual meeting, the group presented its progress in selecting a database platform; items to include in an electronic case report form (eCRF); and standardized operating procedures (SOP) for the collection, processing, storage, and transport of biomaterial. A pilot investigator-initiated study was also proposed that, in addition to addressing an area of unmet need, would allow for the testing of both the eCRF and SOP.