TOFA-PREDICT study protocol: a stratification trial to determine key immunological factors predicting tofacitinib efficacy and drug-free remission in psoriatic arthritis (PsA)

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic, inflammatory, musculoskeletal disease that affects up to 30% of patients with psoriasis. Current challenges in clinical care and research include personalised treatment, understanding the divergence of therapy response and unravelling the multifactorial pathophysiology of this complex disease. Moreover, there is an urgent clinical need to predict, assess and understand the cellular and molecular pathways underlying the response to disease-modifying antirheumatic drugs (DMARDs). The TOFA-PREDICT clinical trial addresses this need. Our primary objective is to determine key immunological factors predicting tofacitinib efficacy and drug-free remission in PsA.

METHODS AND ANALYSIS

In this investigator-initiated, phase III, multicentre, open-label, four-arm randomised controlled trial, we plan to integrate clinical, molecular and imaging parameters of 160 patients with PsA. DMARD-naïve patients are randomised to methotrexate or tofacitinib. Additionally, patients who are non-responsive to conventional synthetic (cs)DMARDs continue their current csDMARD and are randomised to etanercept or tofacitinib. This results in four arms each with 40 patients. Patients are followed for 1 year. Treatment response is defined as minimal disease activity at week 16. Clinical data, biosamples and images are collected at baseline, 4 weeks and 16 weeks; at treatment failure (treatment switch) and 52 weeks. For the first 80 patients, we will use a systems medicine approach to assess multiomics biomarkers and develop a prediction model for treatment response. Subsequently, data from the second 80 patients will be used for validation.

ETHICS AND DISSEMINATION

The study was approved by the Medical Research Ethics Committee in Utrecht, Netherlands, is registered in the European Clinical Trials Database and is carried out in accordance with the Declaration of Helsinki. The study's progress is monitored by Julius Clinical, a science-driven contract research organisation.

TRIAL REGISTRATION NUMBER

EudraCT: 2017-003900-28.

Validation of the 1 μg short synacthen test: an assessment of morning cortisol cut-off values and other predictors

BACKGROUND

Clinical practice shows that many low-dose short synacthen tests (LD-SSTs) for diagnosing adrenal insufficiency in an outpatient setting have a normal outcome and could be considered superfluous. The objective of this study is to provide a guideline to safely reduce the number of unnecessarily performed LD-SSTs.

METHODS

Data of LD-SSTs performed in outpatients were collected. Optimal morning cortisol cut-off values were determined using ROC analysis. Subsequently the predictive value of several variables was tested using univariable and multivariable logistic regression analyses.

RESULTS

A morning cortisol lower cut-off value of 145 nmol/l (specificity 89.9%, positive predictive value 90.0%) and an upper cut-off value of 375 nmol/l (sensitivity 100.0%, negative predictive value 100.0%) were found. Chronic fatigue symptoms and symptoms of hypotension or orthostasis as the main reason for performing the test predict a normal outcome. The use of glucocorticosteroids predicts an abnormal outcome of the LD-SST. Oral, topical, nasal and inhaled glucocorticosteroids are each significant predictors when analysed specifically for predicting central adrenal insufficiency.

CONCLUSION

By using morning cortisol cut-off values of 145 nmol/l and 375 nmol/l instead of the conventional cut-off values, the number of LD-SSTs performed in an outpatient setting can be reduced by 12%, while maintaining high sensitivity and specificity. Furthermore, the outcome of the LD-SST can be predicted by additional variables such as the indication for performing the test and the use of glucocorticosteroids. Different routes of administration of glucocorticosteroids such as inhalation or topical use should be taken into account when central insufficiency is suspected.