Tofacitinib in early active axial spondyloarthritis: protocol of a randomized double-blind, placebo-controlled, multicenter phase IV study, FASTLANE.

BACKGROUND

Early treatment initiation is one of the strongest predictors of good treatment response in axial spondyloarthritis (axSpA). Recently, the Assessment in SpondyloArthritis International Society (ASAS) defined early axSpA as a diagnosis of axSpA with a duration of axial symptoms equal to or less than 2 years. Tofacitinib is a Janus kinase (JAK) inhibitor for the treatment of ankylosing spondylitis.

OBJECTIVES

Compare the efficacy and safety of tofacitinib versus placebo (both on non-steroidal anti-inflammatory drug (NSAID) background) in patients with active early axSpA and inadequate response to at least one NSAID.

DESIGN

This is a phase IV, randomized, double-blind, placebo-controlled, multicenter clinical trial.

METHODS AND ANALYSIS: The study will recruit 104 patients aged ⩾18 and ⩽45 years with active early axSpA (chronic back pain ⩽2 years), inadequate response to at least one NSAID, and objective signs of active inflammation (on magnetic resonance imaging (MRI) of sacroiliac joints (SIJs) or elevated C-reactive protein). Patients will be randomized 1:1 to receive tofacitinib 5 mg twice daily or placebo, with background naproxen 500 mg twice daily for 16 weeks. Patients not meeting early treatment response criteria at week 4 will receive open-label tofacitinib until week 16. Primary and key secondary endpoints at week 16 will be the proportion of patients achieving disease remission (Axial Spondyloarthritis Disease Activity Score <1.3) and change from baseline in MRI SIJ Spondyloarthritis Research Consortium of Canada osteitis score, respectively. Safety will be monitored up to 4 weeks after the last study drug dose.

ETHICS: The study will be performed according to the ethical principles of the Declaration of Helsinki and will be approved by independent ethics committees of each center.

DISCUSSION: This is one of the first randomized clinical trials designed to evaluate the efficacy and safety of a JAK inhibitor in the recently ASAS-defined "early" axSpA population. Trial registration: ClinicalTrials.gov: NCT06112665; CTIS: 2023-505050-18-00.