Objective: Bilastine is a novel second-generation antihistamine. This open-label, single-arm, phase III study evaluated the safety and efficacy of long-term treatment with bilastine in Japanese patients with seasonal (SAR) or perennial allergic rhinitis (PAR). Methods: Patients with SAR or PAR who met the registration criteria and did not violate the exclusion criteria received bilastine (20 mg, once daily) for 12 weeks (treatment period). Patients with PAR who met the transition criteria could elect to continue the bilastine treatment for an additional 40 weeks (continuous treatment period: a total of 52 weeks). Safety and tolerability were the primary outcomes, and the main secondary endpoint was to evaluate changes in efficacy variables from baseline measurements. Results: Fifty-eight patients with SAR and 64 patients with PAR received bilastine (20 mg/day) for 12 weeks. Fifty-five patients with PAR transitioned to the continuous treatment period. Adverse events (AEs) were reported by 17.2% of patients with SAR and by 31.3% of patients with PAR, and adverse drug reactions (ADRs) were reported by 6.3% of patients with PAR but by no patients with SAR during the 12 -week treatment period. All of the ADRs were mild in severity. During the 52 -week treatment period, AEs and ADRs were reported by 73.4% and 6.3% of patients with PAR, respectively. All of the ADRs occurred during the 12 -week treatment period, and none during the continuous treatment period. The AEs were categorized using the System Organ Class of nervous system disorders; 4.7% of patients reported headache, but none reported somnolence. One serious AE was reported, but it was considered to be unrelated to the bilastine treatment. There were no deaths, and no patients withdrew from the study because of AEs. In patients with SAR, bilastine significantly decreased the total nasal symptom score (TNSS), total ocular symptom score (TOSS), and total symptom score (TSS) relative to baseline. Prolonged treatment with bilastine resulted in the maintenance of a significant reduction in TNSS, TOSS, and TSS from the baseline in patients with PAR. Improvement of quality of life was also observed in patients with SAR and PAR. Conclusion: Bilastine was safe, well tolerated, and effective for patients with SAR and PAR. The observed improvement was maintained for the duration of the study, with no loss of drug efficacy. (C) 2016 Elsevier Ireland Ltd. All rights reserved.