A phase 1 pharmacokinetic study of oral NEPA, the fixed combination of netupitant and palonosetron, in Chinese healthy volunteers

Purpose Oral NEPA, the only fixed-combination antiemetic, is composed of the neurokinin-1 receptor antagonist netupitant (300 mg) and the 5-hydroxytryptamine-3 receptor antagonist palonosetron (0.50 mg). This study was conducted to evaluate the pharmacokinetic profile of netupitant and its main metabolites M1 and M3, and palonosetron in Chinese subjects. Oral NEPA tolerability and safety were also analyzed. Methods This was a single-center, single-dose phase 1 study in healthy, adult Chinese volunteers. Eligible subjects received oral NEPA, and blood samples were collected on day 1 predose and at various time points up until day 10 postdose. Pharmacokinetic parameters were analyzed using noncompartmental methods. For safety assessments, adverse events (AEs) were monitored during the study. Results In total 18 Chinese healthy volunteers received oral NEPA. Netupitant mean maximum plasma concentration (C-max) [+/- standard deviation] of 698 +/- 217 ng/mL was reached at 3-6 h, with a mean total exposure (AUC(0-inf)) of 22,000 +/- 4410 h center dot ng/mL. For palonosetron, a mean C-max of 1.8 +/- 0.252 ng/mL was reached at 2-6 h postadministration, with a mean AUC(0-inf) of 81.0 +/- 14.0 h center dot ng/mL. The most common treatment-related AEs in > 2 subjects were constipation (n = 9) and tiredness (n = 3). No severe AEs were observed, and no subject withdrew due to AEs. Conclusion Following single-dose administration of oral NEPA in Chinese subjects, the pharmacokinetic profiles of the NEPA components were mostly similar to those reported previously in Caucasians. NEPA was well tolerated with a safety profile in line with that observed in pivotal trials in Caucasians.