Abstract
Purpose :
GiACTA is the largest trial ever conducted in patients (pts) with giant cell arteritis (GCA), a serious, potentially blinding disease. It is also the first trial in any disease to use a variable-dose, masked corticosteroid (CS) taper, a treatment concept with relevance across the spectrum of immune-mediated ophthalmology indications. The trial hypothesis is that tocilizumab (TCZ) achieves sustained CS-free remission in GCA pts. We report baseline (BL) characteristics of pts with new-onset (new) vs relapsing GCA.
Methods :
The major inclusion criteria are age ≥50 y, historical ESR ≥50 mm/h (or CRP ≥2.45 mg/dL), unequivocal cranial GCA or polymyalgia rheumatica (PMR) symptoms, and positive temporal artery biopsy (TAB) or imaging study showing large-vessel vasculitis (LVV). There are 4 arms: TCZ 162 mg subcutaneous (SC) QW + 6-mo prednisone taper; TCZ 162 mg SC Q2W + 6-mo prednisone taper; 6-mo prednisone taper only; 12-mo taper only. Initial prednisone dose (20-60 mg/d) is at investigator discretion. The taper is masked at doses <20 mg/d.
Results :
Of 251 pts enrolled, 117 (47%) have new GCA and 128 (51%) have relapsing GCA; 77% of new and 80% of relapsing pts met the ACR 1990 criteria for GCA and the study inclusion criteria. At diagnosis, 22% of new and 20% of relapsing pts had PMR symptoms only, 35% and 41% had cranial symptoms only, 43% and 40% had both, and 7% and 13% had ischemia-related vision loss. At BL, 63% of new and 60% of relapsing pts had positive TAB; 50% and 45% had positive imaging. More than one-third had negative TAB/no TAB performed but positive imaging. Common BL comorbidities are in the Table. Mean [SD] BL prednisone dose was 40.5 mg/d [13.0] in new pts vs 29.7 mg/d [11.7] in relapsing pts; 18% of new and 5% of relapsing pts entered the study on 60 mg/d prednisone, and 7% of new and 40% of relapsing pts entered at 20 mg/d.
Conclusions :
Many pts were enrolled based on the large-vessel imaging criterion, reflecting the increasing role of imaging technologies in LVV diagnostics since development of the 1990 ACR criteria. The higher BL prednisone dose in new pts indicates the attempt to prevent acute severe irreversible vision loss, while the lower BL dose in relapsing pts may indicate early detection of relapse and the need to limit toxicity. Relapsing pts also demonstrate more comorbidities, likely due to prolonged CS therapy.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.