Background Glucocorticoids (GC)-related adverse events greatly contribute to the outcome in giant cell arteritis (GCA). There is limited evidence of the efficacy of some DMARDs as steroid-sparing agents in GCA. CYC may be of value in the treatment of systemic vasculitis, including large vessel arteritis.

Objectives Oral cyclophosphamide (CYC) was investigated as a steroid-sparing agent in GCA.

Methods Nineteen patients treated with CYC were retrospectively analyzed. The patients were 16 females and 3 males, with a mean age at disease onset of 70.11±7.94 years. All patients presented with headache at onset; polymyalgia rheumatica (PMR) was associated to GCA in 13/19 patients; 1/19 presented with upper limb claudication and absent radial pulse.

Patients fulfilled at least one of the following 3 characteristics: (a) resistance to GC, i.e., persistence of both symptoms and elevated C reactive protein and/or ESR after induction with 1 mg/kg/day of prednisone given for at least 1 month; (b) disease relapse during high to medium dose of GC therapy (0.3-1 mg kg/day of prednisone); (c) unacceptable risk of GC toxicity, i.e., diabetes mellitus, severe osteoporosis, uncontrolled arterial hypertension, ischemic cardiopathy, cerebrovascular events.

Follow-up ranged from 1 month to nearly 9 years after the end of CYC treatment.

Results Patients starting CYC ab initio for unacceptable risk of GC toxicity were 4/19 (group c). Among the remaining 15 patients, 5 patients were refractory to GC (group a), while 10 patients relapsed during steroid tapering (group b).

The median dose of CYC was 100 mg/day (range 75-150).

Overall, clinical and laboratory efficacy of CYC was observed in 15/19 (78.9%) patients.

CYC was administered for more than three months in 10/19 (52,6%) patients, with response in 9/10.

CYC was administered for 3 months in 5/19 (26,3%) patients, with response in 4/5, and suspension for inefficacy and side effects in the remaining patient.

CYC was administered for less than 3 months in 4/19 (21%) patients with efficacy in 2/4. Treatment suspension occurred for inefficacy in 1/4 and for side effects in 3/4 of these cases.

The follow-up after the completion of CYC treatment varied from 1 month to 100 months. A follow-up ≥6 months after CYC was available in 13/15 patients, and a follow-up ≥12 months after CYC in 11/15 patients. Remission ≥6 months was registered in 12/13 responders, and remission ≥12 months in 10/11 responders.

GC were suspended in 6/15, and they were continued at a dose ≤5 mg/day of prednisone in all the remaining responders. Relapse occurred in 4/15 patients, usually more than 12 months after CYC suspension. Suspension of GC daily dose or reduction ≤5 mg/day of prednisone occurred within the first 6 months of follow-up after the beginning of CYC in 10/15 patients.

Ten adverse events were registered in 9 patients, with recovery usually soon after the suspension of CYC or dose reduction. However, one death occurred due to acute hepatitis.

Conclusions CYC may represent an useful option for patients requiring a prolonged medium to high dose GC therapy and at high risk of GC-related side effects.

Disclosure of Interest None Declared