Maintenance of biologic-free remission with naproxen or no treatment in patients with early, active axial spondyloarthritis: results from a 6-month, randomised, open-label follow-up study, INFAST Part 2

Abstract

Objective: To investigate whether biologic-free remission can be achieved in patients with early, active axial spondyloarthritis (SpA) who were in partial remission after 28 weeks of infliximab (IFX)+naproxen (NPX) or placebo (PBO)+NPX treatment and whether treatment with NPX was superior to no treatment to maintain disease control.

Method: Infliximab as First-Line Therapy in Patients with Early Active Axial Spondyloarthritis Trial (INFAST) Part 1 was a double-blind, randomised, controlled trial in biologic-naïve patients with early, active, moderate-to-severe axial SpA treated with either IFX 5 mg/kg+NPX 1000 mg/d or PBO+NPX 1000 mg/d for 28 weeks. Patients achieving Assessment of SpondyloArthritis international Society (ASAS) partial remission at week 28 continued to Part 2 and were randomised (1:1) to NPX or no treatment until week 52. Treatment group differences in ASAS partial remission and other efficacy variables were assessed through week 52 with Fisher exact tests.

Results: At week 52, similar percentages of patients in the NPX group (47.5%, 19/40) and the no-treatment group (40.0%, 16/40) maintained partial remission, p=0.65. Median duration of partial remission was 23 weeks in the NPX group and 12.6 weeks in the no-treatment group (p=0.38). Mean Bath Ankylosing Spondylitis Disease Activity Index scores were low at week 28, the start of follow-up treatment (NPX, 0.7; no treatment, 0.6), and remained low at week 52 (NPX, 1.2; no treatment, 1.7).

Conclusions: In axial SpA patients who reached partial remission after treatment with either IFX+NPX or NPX alone, disease activity remained low, and about half of patients remained in remission during 6 months in which NPX was continued or all treatments were stopped.

Keywords: NSAIDs; Spondyloarthritis; TNF-alpha.

Figure 1

Patient disposition for INFAST Part 2. ASAS, Assessment of SpondyloArthritis international Society; INFAST, Infliximab as First-Line Therapy in Patients with Early Active Axial Spondyloarthritis Trial; ITT, intent-to-treat; NPX, naproxen.

Figure 2

Percentage of patients in INFAST Part 2 who had ASAS partial remission (A) and low disease activity (BASDAI<3 in patients with nonmissing data) (B) at each visit. ASAS, Assessment of SpondyloArthritis international Society; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; ET, early termination; INFAST, Infliximab as First-Line Therapy in Patients with Early Active Axial Spondyloarthritis Trial; NPX, naproxen; Wk, week.

Figure 3

Mean BASDAI (A), ASDAS-C (B), CRP (C) and BASFI (D) from baseline to week 52 for patients who participated in INFAST Part 2. ^aDuring the follow-up period, patients with ASAS partial remission were assigned to either NPX or no treatment, with assignments stratified by initial treatment group. ASAS, Assessment of SpondyloArthritis international Society; ASDAS-C, Ankylosing Spondylitis Disease Activity Score based on CRP; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; CRP, C-reactive protein; IFX, infliximab; NPX, naproxen; PBO, placebo; VAS, visual analogue scale; Wk, week.

Figure 4

BASDAI (A) and ASDAS-C (B) by treatment sequence and visit for patients who participated in Part 2. ^aDuring the follow-up period, patients with ASAS partial remission were assigned to either NPX or no treatment, with assignments stratified by initial treatment group. ASAS, Assessment of SpondyloArthritis international Society; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; IFX, infliximab; NPX, naproxen; PBO, placebo; Wk, week.