Tbo-Filgrastim Can Replace Filgrastim During ASCT in Myeloma and Lymphoma

A study presented at the annual meeting of the American Society of Hematology concluded that tbo-filgrastim is similar to filgrastim for ASCT mobilization in patients with MM or NHL.

Tbo-filgrastim has been approved in Europe for all indications of filgrastim, the parent drug, but not in the United States. While filgrastim has been approved for treating neutropenia following chemotherapy as well as for mobilization of hematopoietic progenitors for autologous stem cell transplantation (ASCT), tbo-filgrastim has only been approved for neutropenia.

To compare the efficacy of the 2 treatments, a randomized phase 2 study was conducted at the Washington University School of Medicine, to evaluate the effect of filgrastim and tbo-filgrastim on peripheral blood (PB) CD34+ counts, CD34+ apheresis yield, toxicity, and post-ASCT engraftment in patients with multiple myeloma (MM) or non-Hodgkin lymphoma (NHL).

According to the study presented at the annual meeting of the American Society of Hematology, participants were randomized to the tbo-filgrastim or filgrastim group, and were administered either drug (10 µg/kg) once daily for 5 days. On the evening of day 4, plerixafor (0.24 mg/kg) was administered; apheresis was performed on Day 5. If a participant failed to achieve the target collection goal (5.0x106 cells/kg) on day 5, he/she continued to receive daily tbo-filgrastim/filgrastim, plerixafor, and apheresis for a maximum of 3 additional days. Participants who subsequently underwent ASCT were followed for platelet and neutrophil engraftment.

The study found similar post-mobilization PB CD34+ counts in both study arms: 20/µL for tbo-filgrastim and 22/µL for filgrastim (P = .647) on day 4. Pre-apheresis was for 94/µL for tbo-filgrastim and 92/µL for filgrastim (P = .726) on day 5. CD34+ apheresis yield was also similar between the arms: the median day 5 CD34+/kg apheresis yield was 10.9x106 for tbo-filgrastim and 12.0x106 for filgrastim (P = .88). Toxicity was similar between the arms as well, the study reported.

Based on the results the authors concluded that tbo-filgrastim is similar to filgrastim for ASCT mobilization in patients with MM or NHL.