Background and objectives: Ropeginterferon alfa-2b is a novel monopegylated recombinant interferon alfa-2b for the treatment of patients with polycythemia vera. The objectives of this study were to evaluate the pharmacokinetics, pharmacodynamics, safety, and tolerability of ropeginterferon alfa-2b in healthy Japanese subjects compared with Caucasian subjects.
Methods: In this multicenter, parallel-group phase I study, a cohort consisting of six Japanese and six Caucasian subjects was designated to receive a single subcutaneous dose of ropeginterferon alfa-2b (100, 200, 300, and 450 µg). Pharmacokinetic and pharmacodynamic parameters, and immunogenicity were evaluated. Safety was assessed throughout the study.
Results: Cohort 4 (450-µg dose) was not initiated because the primary objective of this study was achieved based on the three completed cohorts. A total of 36 enrolled subjects (18 Japanese and 18 Caucasian) in three cohorts were included in the safety, pharmacokinetic, and pharmacodynamic analysis sets. Ropeginterferon alfa-2b exposure in terms of the area under the serum concentration-time curve (AUC) from time zero extrapolated to infinity and the AUC from time zero to the time of the last quantifiable concentration was approximately 1.7-fold and two-fold higher in Japanese subjects than in Caucasian subjects, respectively. Across the same dose range, the maximum serum concentration was approximately 1.25-fold higher in Japanese subjects than in Caucasian subjects. The time to reach the median maximum serum concentration was similar between ethnicities (approximately 96-111 h). The terminal half-life was 48-57 h in Japanese subjects and 31-75 h in Caucasian subjects. The slope of the relationship between dose and drug exposure was greater than 1 in both ethnicities. The dose-dependent induction of beta-2 microglobulin and neopterin expression was observed in both ethnicities, and the two groups showed similar pharmacodynamic parameters. At the end of the study, 22.2% of Japanese subjects and 11.1% of Caucasian subjects developed anti-ropeginterferon alfa-2b-binding antibodies. The neutralizing capacity of these antibodies was not tested. Ropeginterferon alfa-2b up to 300 µg was safe and well tolerated, with no unexpected safety findings based on previous experiences with ropeginterferon alfa-2b and other forms of interferon.
Conclusions: Ropeginterferon alfa-2b exposure was higher in Japanese subjects than in Caucasian subjects. The increase in ropeginterferon alfa-2b exposure was greater than the dose proportion in the dose range of 100-300 µg. Ropeginterferon alfa-2b was safe and well tolerated.
Clinical trial registration: ClinicalTrials.gov identifier NCT03546465, registered on 6 June, 2018.