Clinical safety and efficacy of "filgrastim biosimilar 2" in Japanese patients in a post-marketing surveillance study.

We conducted a post-marketing surveillance to evaluate the safety and efficacy of TKN732, approved as "filgrastim biosimilar 2", in Japanese patients who developed neutropenia in the course of cancer chemotherapy or hematopoietic stem cell transplantation. A total of 653 patients were registered during the 2-year enrollment period starting from May 2013, and 627 and 614 patients were eligible for safety and efficacy analyses of the G-CSF biosimilar, respectively. Forty-three adverse drug reactions were reported in 33 patients (5.26%). Back pain was most frequently observed and reported in 20 patients (3.19%), followed by pyrexia (1.28%) and bone pain (0.96%). Risk factors for adverse reactions identified by logistic regression analyses were younger age, presence of past medical history, and lower total dose at the onset of adverse reactions. Among the 576 cancer patients who developed Grade 2-4 neutropenia after chemotherapy, recovery to Grade 1/0 was reported in 553 patients (96%) following filgrastim biosimilar 2 treatment. The median duration of neutrophil counts below 1500/μL was 5 days. In addition, all 11 patients who underwent hematopoietic stem cell transplantation had good responses to filgrastim biosimilar 2. In conclusion, this study showed that filgrastim biosimilar 2 has a similar safety profile and comparable effects to the original G-CSF product in the real world clinical setting.