Comparative study of the number of report and time‐to‐onset of the reported adverse event between the biosimilars and the originator of filgrastim

Purpose The objective of this study is to specify the most reported adverse events as preferred terms (PTs) and to compare the reported adverse events about some properties including the number of report and time-to-onset (TTO) distribution of the originator of filgrastim Neupogen® and its biosimilars in Europe, using VigiBase®. Methods We identified the biosimilar which was reported as the suspected drug in more than 100 individual case safety reports in Europe. Then, we specified the top ranking 10 PTs in the cases reported with Neupogen® or each biosimilar as the suspected drug. We also compared the TTO of the most reported PTs using the data about the onset date of the PT and the start date of filgrastim. We used Kolmogorov–Smirnov method to detect significant difference. Results The total ICSR numbers with Neupogen® and 3 biosimilars, Zarzio®, Nivestim®, and Tevagrastim® were 1,301, 295, 156, and 127, respectively, in Europe. The most reported PTs with Neupogen® were bone pain, pyrexia, and dyspnoea. The TTO of bone pain and pyrexia with Zarzio® (N: 22 and 16, median: 1 and 0.5 days) were significantly shorter than those with Neupogen® (P < 0.01, N: 72 and 33, median: 3.5 and 3 days), respectively. The most reported PTs with biosimilars were drug ineffective and neutropenia. Conclusion The difference in the TTO was identified between originator filgrastim Neupogen and its biosimilar regarding some PTs, which may suggest the difference in their safety profile. Copyright © 2017 John Wiley & Sons, Ltd.