Background/Purpose:

Adalimumab (ADA) is currently approved in the EU for the treatment of severe non-radiographic axial spondyloarthritis (nr-axSpA), in patients (pts) with an elevated CRP and/or positive MRI who have had an inadequate response to, or are intolerant to NSAIDs. Short-term and 1 year (yr) remission data have been previously reported for the ABILITY-1 trial. The objective of this analysis was to determine drug survival and durability of clinical remission at yr 2 among pts with nr-axSpA.

Methods:

ABILITY-1 is an ongoing phase 3, double blind (DB), randomized, controlled trial in pts with nr-axSpA who had an inadequate response, intolerance, or contraindication to NSAIDs. A 12-wk DB period of ADA 40 mg every other week (eow) or placebo (PBO) was followed by an open-label (OL) extension phase in which pts could receive OL ADA 40 mg eow for up to an additional 144 wks. This post hoc analysis evaluated the wk 104 efficacy and safety of ADA in the MRI+/CRP+ nr-axSpA subpopulation, defined as pts who had a positive baseline (BL) MRI (SPARCC score ≥2 for either the SI joints or spine) or an elevated CRP at BL. Clinical remission was defined by ASDAS inactive disease (ASDAS ID, ASDAS <1.3) or by ASAS partial remission (ASAS PR). Sustained remission was defined as achieving clinical remission at wks 52, 80, and 104. Clinical responses were summarized by observed case analysis. Safety was assessed in terms of adverse events (AE).  

Results:

142 (69 ADA, 73 PBO) of the total efficacy population (N=185) were in the MRI+/CRP+ subpopulation; 107 (75%) had data available for wk 104 analysis. The table lists clinical response and sustained remission rates for the MRI+/CRP+ subpopulation. Sustained remission rates were similar between pts with symptom duration <5 vs. ≥5 years (sustained ASDAS ID 38% vs. 31%; sustained ASAS PR 26% vs. 29%). Among pts exposed to ADA during the study (356.2 patient-yrs [PY] of exposure) there were 8 serious infections (2.2/100 PY, including 1 case of disseminated TB), 1 case of lupus-like syndrome, and 2 deaths (suicide and cardiopulmonary failure due to opiate toxicity). No malignancies or demyelinating diseases have been reported.

         

Table. Clinical Responses in MRI+/CRP+ Subpopulation (Completers Analysis)a
	Week 104 (N=107) (%)	Sustained Remission at Weeks 52, 80 and 104 (%)
ASAS20	82	—
ASAS40	66	—
BASDAI50	69	—
ASDAS inactive disease	49b	35d
ASAS partial remission	44c	28e
aData as observed. bN=105, cN=104; dN=101 and eN=102 pts with available data at wks 52, 80 and 104.

Conclusion:

Almost half of the pts who remained on long-term ADA therapy in ABILITY-1 were in remission at wk 104, the majority of whom were also in this state of remission at wks 52 and 80. Long-term safety data are comparable to the known AE rates with ADA in other rheumatology indications.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/sustained-clinical-remission-in-patients-with-non-radiographic-axial-spondyloarthritis-after-two-years-of-adalimumab-treatment/