AB0508 Fixed, low-dose hydroxichloroquine versus weight-adjusted dose in systemic lupus erythematosus patients with low activity

Background Optimal hydroxichloroquine (HCQ) dose to reduce ocular toxicity risk is 5 mg/kg or actual weight daily, according to new recommendations. In systemic lupus erythematosus patients (SLE) with low or no disease activity, fixed low-dose HCQ might be equally effective in relapse prevention weight-adjusted doses, thus resulting in lower cumulative dose. Objectives Our aim was to compare a fixed dose of HCQ 200 mg daily with a weight-adjusted dose (5 mg/kg of actual weight daily) in SLE patients with low activity. Methods SLE activity was assessed using the SLE Disease Activity Index (SLEDAI-2K), the Safety of Oestrogen in Lupus Erythematosus National Assessment (SELENA)-SLEDAI and the Physician Global Assessment (PGA, 0–3 scale) in each visit. Low-activity SLE (LLDAS) was defined according to Franklyn et al: 1) a SLEDAI-2K score ≤4, 2) no new SLE-related activity events compared with the previous visit, 3) a PGA score ≤1, 4) prednisone dose ≤7.5 mg daily and 5) stable doses of maintenance immunosuppressant therapy. LLDAS was evaluated at baseline and months 3 and 6. In order to adjust doses to weight, and given the impossibility of fractionating HCQ tablets, the adjusted dose was calculated for every week. For example, for 62 kg patient, the calculated dose would be 5 mgx52 kg=260 mg daily, which would mean 1820 mg weekly. Therefore, the patient would receive 400 mg daily for 2 days and 200 mg daily for 5 days every week. A relapse was defined as an increase of SLEDAI scores≥3, according to current recommendations Results A total of 50 LLDAS patients were compared, 25 with a fixed dose and 25 with a weight-adjusted dose. No significant differences regarding body weight between groups were observed: 52 kg (41–58.5 kg) vs. 51 kg (44–55 kg). Baseline activity scale scores were not significantly different. No patient relapsed on follow-up in either of both groups. Finally, the mean HCQ cumulative dose at 6 months was reduced by approximately 9.6 grams. Conclusions In LLADS patients, a fixed HCQ dose of 200 mg daily may be as effective as the weight-adjusted dose in preventing disease relapses, thus resulting in a decrease in the HCQ cumulative dose and, therefore, a reduction of the risk of ocular toxicity. Reference [1] Franklyn K, Lau CS, Navarra SV, et al. Definition and initial validation of a Lupus Low Disease Activity State (LLDAS). Ann Rheum Dis. 2016;75:1615–21. Disclosure of Interest None declared