The Pharmacodynamics, Pharmacokinetics, and Safety of Arhalofenate in Combination with Febuxostat When Treating Hyperuricemia Associated with Gout.

OBJECTIVE: Arhalofenate (ARH), in development for gout, has uricosuric and anti-flare activities. ARH plus febuxostat (FBX) were evaluated in subjects with gout for serum uric acid (SUA) lowering, drug interaction, and safety. METHODS: Open phase II trial in gout volunteers (NCT02252835). Cohort 1 received ARH 600 mg for 2 weeks, followed by sequential 1-week co-administration of FBX 80 mg followed by 40 mg. FBX 40 mg was continued alone for 2 weeks. Cohort 2 received ARH 800 mg for 2 weeks, followed by sequential 1-week co-administration of FBX 40 mg followed by 80 mg. FBX 80 mg was continued alone for 2 weeks. SUA, its fractional excretion (FEUA), and plasma oxypurines were assessed. Pharmacokinetics of FBX and ARH were determined alone and in combination for cohort 2. RESULTS: Baseline mean SUA was 9.4 mg/dl for cohort 1 (n = 16) and 9.2 mg/dl for cohort 2 (n = 16). The largest SUA decrease (63%) was observed with ARH 800 mg + FBX 80 mg, with all subjects reaching SUA < 6 mg/dl and 93% < 5 mg/dl. The area under the curve (AUC)(0-t) of ARH acid + FBX/ARH acid was 108%. The AUC(0-t) of FBX + ARH acid/FBX was 87%. As expected, FBX increased oxypurines and increases were unaffected by ARH co-administration. Baseline FEUA were low (3.5%-4.6%) and ARH increased them toward normal without overexcretion of UA. ARH was well tolerated and appeared safe. CONCLUSION: ARH and FBX lowered SUA by complementary mechanisms. The combination provided greater decreases than each drug alone. The combination was well tolerated and appeared safe. TRIAL REGISTRATION: NCT02252835.

A Randomized, Double-Blind, Active- and Placebo-Controlled Efficacy and Safety Study of Arhalofenate for Reducing Flare in Patients With Gout.

OBJECTIVE: Arhalofenate is a novel antiinflammatory uricosuric agent. The objective of this study was to evaluate its antiflare activity in patients with gout. METHODS: This was a 12-week, randomized, double-blind, controlled phase IIb study. Eligible patients had had ≥3 flares of gout during the previous year, had discontinued urate-lowering therapy and colchicine, and had a serum uric acid (UA) level of 7.5-12 mg/dl. Patients were randomly assigned at a 2:2:2:2:1 ratio to receive 600 mg arhalofenate, 800 mg arhalofenate, 300 mg allopurinol, 300 mg allopurinol plus 0.6 mg colchicine, or placebo once a day. The primary outcome measure was the flare incidence (number of flares divided by time of exposure). The serum UA level was a secondary outcome measure. RESULTS: A total of 239 gout patients were randomized and took at least 1 dose of study medication. The primary outcome measure comparing flare incidence between 800 mg arhalofenate and 300 mg allopurinol was achieved, with a 46% decrease in the 800 mg arhalofenate group (0.66 versus 1.24; P = 0.0056). Treatment with 800 mg arhalofenate was also significantly better than placebo (P = 0.049) and not significantly different from treatment with 300 mg allopurinol plus 0.6 mg colchicine (P = 0.091). Mean changes in serum UA level were -12.5% with 600 mg arhalofenate and -16.5% with 800 mg arhalofenate (P = 0.001 and P = 0.0001, respectively, versus -0.9% with placebo). There were no meaningful differences in adverse events (AEs) between groups, and there were no serious AEs related to arhalofenate. Urinary calculus occurred in 1 patient receiving 300 mg allopurinol. No abnormal serum creatinine values >1.5-fold the baseline value were observed in the arhalofenate-treated groups. CONCLUSION: Arhalofenate at a dosage of 800 mg decreased gout flares significantly compared to allopurinol at a dosage of 300 mg. Arhalofenate was well tolerated and appeared safe. Arhalofenate is the first urate-lowering antiflare therapy.