A Study of Clinical and Immune Responses to Sequential Biologic Therapies in Psoriatic Arthritis (STRIDE-PsA)

May 12, 2026 updated by: Royal United Hospitals Bath NHS Foundation Trust

STRIDE-PsA: A Study of Treatment Response and Immunogenicity in Sequential Biologic and Targeted Synthetic Disease-Modifying Antirheumatic Drug (b/tsDMARD) Exposure in Psoriatic Arthritis

The goal of this observational study is to evaluate how well advanced therapies work in adults with psoriatic arthritis (PsA) who are starting a biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) as part of routine care.

The main questions are:

  • Do treatment responses differ according to the number of previous advanced therapies?
  • Can anti-drug antibodies (ADAs) or blood drug levels help predict treatment effectiveness?

Researchers will compare participants receiving earlier-line versus later-line advanced therapies to assess differences in treatment response and antibody development.

Participants will allow collection of routine clinical assessment data, complete questionnaires on symptoms and quality of life, and provide blood samples before treatment and at 12 weeks.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Study Design and Objectives

STRIDE-PsA is a prospective, multicentre observational cohort study conducted within routine NHS rheumatology care. Approximately ten NHS sites will recruit adults with psoriatic arthritis (PsA) initiating a new biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD). Participants will be followed for 52 weeks with assessments at baseline and weeks 4, 12, 24, and 52. As this is a non-interventional study, treatment decisions and clinical management will remain at the discretion of the treating clinician.

The study aims to evaluate treatment effectiveness across different lines of advanced therapy and to investigate whether anti-drug antibodies (ADAs) or circulating drug levels are associated with clinical response. The underlying hypothesis is that patients may achieve comparable clinical improvement despite multiple prior therapy switches.

Study Procedures and Data Collection

Participants will be followed for 52 weeks with assessments aligned to routine NHS rheumatology care. Data collection will include clinical examinations, patient-reported outcome measures (PROMs), and blood sampling for ADA and drug level analysis.

At baseline, informed consent will be obtained and demographic and clinical history recorded. Participants will undergo routine clinical assessment to derive disease activity measures (including cDAPSA, BSA, and minimal disease activity status), complete validated PROMs (PSAID-9, HAQ-DI, PGADA), and provide routine NHS blood tests. An additional small research blood sample will be collected, where feasible alongside routine bloods.

Follow-up assessments will occur at approximately Weeks 4, 12, 24, and 52. PROMs will be collected at each follow-up time point, with repeat clinical examination and a second research blood sample at Week 12 during routine care visits. Information on suspected treatment-related adverse events identified during routine clinical review will be recorded throughout follow-up.

All procedures are designed to align with standard NHS appointments to minimise additional participant burden, and visit windows are permitted to allow flexibility in scheduling.

Recruitment and Follow-up

Potential participants will be identified during routine rheumatology appointments by the direct care team and provided with study information. Written informed consent will be obtained by trained research staff prior to any study-specific procedures. Participants may provide consent on the day of approach or after further consideration, according to preference.

Sample Size Rationale

The primary analysis will compare mean change in cDAPSA from baseline to Week 12 between patients initiating 4th/5th-line versus 2nd/3rd-line b/tsDMARD. The non-inferiority margin is set at -5.7 cDAPSA points, based on published estimates of the minimally clinically important difference, and the investigators assume SD = 12.36 for the 12-week change from published data. With one-sided α = 0.05 and 80% power, the required sample size is ~58 per group. Allowing for 10% drop out, this gives 65 per group, for a total of 130 participants across the two primary groups (equal allocation). Patients initiating first-line therapy and those on 6th-line or beyond will also be recruited as descriptive comparative cohorts. To ensure adequate precision for secondary endpoints (including patient-reported outcomes and quality-of-life measures) and to support regression analyses of treatment sequencing, the investigators plan to over-recruit, aiming for approximately 100 patients in each of the four groups (1st line, 2nd/3rd, 4th/5th, and 6th+; ≈400 total). Based on pilot data from Bath, which indicates around 80 patients have been commenced on b/tsDMARD therapy over a year, the investigators anticipate that recruitment from ten sites with a 50% consent rate will allow us to meet our recruitment target over 18 months.

Bias, Confounding, and Data Quality

Given the observational design, several strategies will be implemented to minimise bias. Screening logs will be maintained to evaluate recruitment patterns and potential selection bias. Analyses will adjust for pre-specified confounders, including study site, age, sex, baseline disease activity, disease duration, and comorbidities. Standardised electronic case report forms, validated PROMs, and site training will be used to reduce information bias.

Standardised data collection forms, training of research staff, and use of validated patient-reported outcome measures will minimise variation in data collection across sites. Loss to follow-up will be monitored, and reasons recorded where available. Sensitivity analyses will explore the impact of missing data, including multiple imputation where appropriate.

Statistical Analysis

The primary endpoint is change in cDAPSA score from baseline to Week 12. A non-inferiority margin of -5.7 points has been pre-specified based on published minimally clinically important difference thresholds. Change in cDAPSA will be analysed using analysis of covariance (ANCOVA), adjusting for baseline cDAPSA, age, sex, disease duration, relevant comorbidities, and study centre. A one-sided α = 0.05 will be used. Analyses will be conducted in both intention-to-treat and per-protocol populations.

Secondary endpoints will be analysed using regression models with covariate adjustment consistent with the primary analysis.

Achievement of minimal disease activity (MDA) at Week 12 and composite clinical response (cDAPSA low disease activity plus BSA <1%) will be analysed using logistic regression. Continuous change in skin involvement (body surface area, BSA) will be analysed using analysis of covariance (ANCOVA), with logistic regression used for categorical skin response thresholds.

Patient-reported outcomes, including health-related quality of life (PsAID-9), physical function (HAQ-DI), and patient global assessment (PGADA), will be analysed using ANCOVA models adjusting for baseline values and predefined covariates.

Treatment persistence will be evaluated using Kaplan-Meier survival analysis and Cox proportional hazards regression. Flare outcomes, as measured by the PsA Flare questionnaire, will be analysed using logistic regression.

Anti-drug antibody (ADA) outcomes will be summarised descriptively, including prevalence, incidence, and titre distribution by therapy line. Exploratory analyses will assess associations between ADA status or titres, circulating drug levels, clinical response, treatment-related adverse events, and treatment persistence using appropriate multivariable models.

Missing data are anticipated due to incomplete follow-up. The primary analysis will assume data are missing at random and will use multiple imputation for continuous and binary Week-12 endpoints, incorporating baseline values and predefined covariates. Sensitivity analyses will include complete-case analyses and conservative assumptions for binary outcomes. For time-to-event endpoints, participants lost to follow-up will be right-censored at the last known treatment date, and event times will not be imputed.

Study Type

Observational

Enrollment (Estimated)

400

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: James Kimpton, BA (Hons) BM BCh (oxon) MRCP
  • Phone Number: +44 01225 824160
  • Email: james.kimpton@nhs.net

Study Locations

  • United Kingdom
      • Bath, United Kingdom
        • Royal United Hospitals Bath NHS Foundation Trust
        • Contact:
        • Principal Investigator:
          • James Kimpton, BA (Hons) BM BCh (oxon) MRCP

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adults with a confirmed diagnosis of PsA, meeting CASPAR classification criteria, who are initiating a new advanced therapy (b/tsDMARD) as part of routine NHS care.

Description

Inclusion Criteria:

  • Age ≥18 years
  • Clinical diagnosis of PsA meeting CASPAR criteria
  • Starting a new b/tsDMARD, irrespective of line of therapy

Exclusion Criteria:

  • Switching b/tsDMARD therapy for psoriasis or spondyloarthritis alone, without active psoriatic arthritis.
  • Previous treatment with the same b/tsDMARD being started at baseline.
  • Inability or unwillingness to provide informed consent.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
First-line Advanced Therapy
Participants with PsA initiating their first biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) as part of routine NHS clinical care. Treatment is prescribed by the treating clinician and not assigned by the study.
Drug: Biologic or targeted synthetic DMARD (b/tsDMARD)

This is a non-interventional observational study. Participants will receive biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) as part of routine NHS clinical care, and no treatment will be assigned by the study.

Participants will be categorised into cohorts according to the line of advanced therapy being initiated at study entry (first line, second/third line, fourth/fifth line, and sixth line or beyond). The study will evaluate treatment outcomes, circulating drug levels, and anti-drug antibody (ADA) status across these treatment-line groups. All treatment decisions remain at the discretion of the treating clinician.
Second/Third-line Advanced Therapy
Participants with PsA initiating a second or third b/tsDMARD following prior advanced therapy exposure. All treatments are part of routine clinical care.
Drug: Biologic or targeted synthetic DMARD (b/tsDMARD)

This is a non-interventional observational study. Participants will receive biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) as part of routine NHS clinical care, and no treatment will be assigned by the study.

Participants will be categorised into cohorts according to the line of advanced therapy being initiated at study entry (first line, second/third line, fourth/fifth line, and sixth line or beyond). The study will evaluate treatment outcomes, circulating drug levels, and anti-drug antibody (ADA) status across these treatment-line groups. All treatment decisions remain at the discretion of the treating clinician.
Fourth/Fifth-line Advanced Therapy
Participants with PsA initiating a fourth or fifth b/tsDMARD as part of routine care after multiple prior advanced therapy switches.
Drug: Biologic or targeted synthetic DMARD (b/tsDMARD)

This is a non-interventional observational study. Participants will receive biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) as part of routine NHS clinical care, and no treatment will be assigned by the study.

Participants will be categorised into cohorts according to the line of advanced therapy being initiated at study entry (first line, second/third line, fourth/fifth line, and sixth line or beyond). The study will evaluate treatment outcomes, circulating drug levels, and anti-drug antibody (ADA) status across these treatment-line groups. All treatment decisions remain at the discretion of the treating clinician.
Sixth-line or Later Advanced Therapy
Participants with PsA initiating a sixth or subsequent b/tsDMARD during routine clinical care.
Drug: Biologic or targeted synthetic DMARD (b/tsDMARD)

This is a non-interventional observational study. Participants will receive biologic or targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) as part of routine NHS clinical care, and no treatment will be assigned by the study.

Participants will be categorised into cohorts according to the line of advanced therapy being initiated at study entry (first line, second/third line, fourth/fifth line, and sixth line or beyond). The study will evaluate treatment outcomes, circulating drug levels, and anti-drug antibody (ADA) status across these treatment-line groups. All treatment decisions remain at the discretion of the treating clinician.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Clinical Disease Activity in Psoriatic Arthritis (cDAPSA)
Time Frame: Weeks 0/12

The cDAPSA is the primary outcome and is a validated composite measure of disease activity in PsA. It is calculated as the sum of the tender joint count (0-68 joints), swollen joint count (0-66 joints), patient global assessment of disease activity (0-10 cm visual analogue scale), and patient assessment of arthritis pain (0-10 cm VAS). Unlike the full DAPSA, cDAPSA does not include C-reactive protein.

Scores provide a continuous measure of disease activity, with established thresholds to categorise disease states: remission (≤4), low disease activity (>4-13), moderate disease activity (>13-27), and high disease activity (>27).
Weeks 0/12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Body Surface Area of Psoriasis (BSA)
Time Frame: Week 0/12

In the BSA assessment, the patient's hand (including the palm, fingers, and thumb) will be used as the reference point for measuring how much of their skin is affected by psoriasis, representing roughly 1% of the body's surface.

The BSA palm method will be used for the evaluation of BSA affected by psoriasis as follows:

  • Head and neck=10% (10 palms)
  • Upper extremities=20% (20 palms)
  • Trunk=30% (30 palms)
  • Lower extremities=40% (40 palms)
  • Total BSA=100%
Week 0/12
Minimal Disease Activity (MDA)
Time Frame: Weeks 0/12

Minimal Disease Activity (MDA) is a validated composite outcome used in psoriatic arthritis to define a state of low disease activity across the main clinical domains. A patient is considered to have achieved MDA if they meet at least 5 out of the following 7 criteria:

  1. Tender joint count ≤1
  2. Swollen joint count ≤1
  3. Psoriasis-affected body surface area (BSA) ≤3%
  4. Patient pain visual analogue scale (VAS) ≤15 mm
  5. Patient global assessment of disease activity VAS ≤20 mm
  6. Health Assessment Questionnaire-Disability Index (HAQ-DI) ≤0.5
  7. Tender entheseal points ≤1
Weeks 0/12
Psoriatic Arthritis Impact of Disease-9 (PsAID-9)
Time Frame: Weeks 0/4/12/24/52

The PsAID-9 is a short, validated tool designed to capture the impact of psoriatic arthritis from the patient's perspective [14]. It consists of nine domains that patients rate on a 0-10 numerical rating scale, where higher scores indicate worse status. The domains are: pain, fatigue, skin problems, work/leisure activities, functional capacity, discomfort, sleep disturbance, coping, and anxiety/fear.

Each domain is weighted according to its relative importance, and an overall weighted mean score (0-10) is calculated. A score below 4 is generally considered to represent a patient-acceptable symptom state.
Weeks 0/4/12/24/52
Health Assessment Questionnaire-Disability Index (HAQ-DI)
Time Frame: Weeks 0/4/12/24/52
The HAQ-DI contains 20 items divided into 8 domains that measure: dressing and grooming, arising, eating, walking, hygiene, reach, grip, and common daily activities. Study participants will be required to indicate the degree of difficulty they experience in each domain in the past week on a 4-point scale that ranges from 0 (without difficulty) to 3 (unable to do). The HAQ-DI score ranges from 0 to 3. A lower HAQ-DI score indicates an improvement in function.
Weeks 0/4/12/24/52
Patients' Global Assessment of Disease Activity (PGADA VAS)
Time Frame: Weeks 0/4/12/24/52
The study participant's global assessment of disease activity (PGADA) will be performed using a 100mm visual analog scale (VAS) scale where 0 is "very good, no symptoms" and 100 is "very poor, severe symptoms". The study participant will be asked the following question: "In all the ways in which your psoriasis and arthritis, as a while, affects you, how would you rate the way you felt over the past week?". The study participant will be asked to consider his/her arthritis symptoms and functional capacity in their response to this question.
Weeks 0/4/12/24/52
Duration of time on b/tsDMARD
Time Frame: Weeks 0/4/12/24/52
Duration on b/tsDMARD therapy will be defined as the time in weeks from the date of first dose to the date of permanent discontinuation for any reason (including inefficacy, adverse events or patient choice). Patients who remain on therapy at last follow-up will be censored at that date. If there has been any period of time off treatment deemed by the treating physician to be clinically impactful, the patient will be excluded from the study.
Weeks 0/4/12/24/52
Patient completed disease flare questionnaire (FLARE)
Time Frame: Weeks 0/4/12/24/52
The PsA Flare Questionnaire is a validated, patient-completed tool designed to capture episodes of disease flare from the patient's perspective. It consists of ten yes/no items covering key disease domains, including: joint pain and swelling, skin psoriasis, impact of activities of daily living, mobility, frustration, depression, tiredness and a change in number or combination of symptoms from PsA. Each "yes" response scores one point, giving a total score from 0 to 10. A threshold of ≥4 has been shown to represent a clinically meaningful flare.
Weeks 0/4/12/24/52
Anti-drug antibody (ADA) and non-trough drug levels
Time Frame: Weeks 0/12
ADAs will be measured using standardised, in-house sandwich enzyme-linked immunosorbent assays (ELISA) developed at the University of Bath. These assays are designed to be fully drug-tolerant, allowing detection of ADAs despite the presence of circulating drug, and include assessment of neutralising ADAs, addressing key limitations of many previous immunogenicity studies in PsA. Unlike most previous studies, which have primarily measured total ADAs alone, the investigators will also be able to characterise immunoglobulin isotypes, including IgM, IgE, IgA and IgG subclasses (IgG1-4), providing potential relevance to ADA effector mechanisms.
Weeks 0/12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Royal United Hospitals Bath NHS Foundation Trust

Collaborators

University of Bath

Investigators

  • Principal Investigator: James Kimpton, BA (Hons) BM BCh (oxon) MRCP, Royal United Hospitals Bath NHS Foundation Trust

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 1, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

February 11, 2026

First Submitted That Met QC Criteria

February 11, 2026

First Posted (Actual)

February 18, 2026

Study Record Updates

Last Update Posted (Actual)

May 13, 2026

Last Update Submitted That Met QC Criteria

May 12, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 362489

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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