Evaluation of a biosimilar granulocyte colony-stimulating factor for peripheral blood stem cell mobilization in Japanese healthy donors: a prospective study.

A "biosimilar" is a biotechnological product with a lower cost profile and equivalent efficacy and safety to the originator, but post-marketing clinical evaluation of biosimilar products has not been adequately conducted. We prospectively investigated the utility of biosimilar filgrastim in 13 peripheral blood stem cell (PBSC) donors from June 2014 to January 2017. In addition, we retrospectively compared these to another 13 PBSC donors mobilized with the originator filgrastim in the same period. Donor characteristics were equivalent between the groups. The median number of CD34+ cells per donor body weight (BW) and blood volume processed (BV) were 4.87 × 106/kg and 25.5 × 103/mL in the biosimilar group and 4.93 × 106/kg and 16.6 × 103/mL in the originator group, respectively. There were no significant differences between the groups in the number of CD34+ cells per donor BW or BV. All adverse events associated with G-CSF were permissive. The total G-CSF cost was significantly lower in the biosimilar group than in the originator group. These findings suggest that biosimilar filgrastim has the same efficacy and short-term safety as originator filgrastim for PBSC mobilization in healthy donors, with economic superiority. Longer follow-up studies are needed to evaluate the incidence of long-term adverse events.

Efficacy of three filgrastim-intended copies for hematopoietic stem cell mobilization in healthy adult and pediatric donors in Mexico.

INTRODUCTION: The use of filgrastim biosimilars for healthy adult and pediatric donor mobilization in hematopoietic stem cell transplantation has been met with increased safety and efficacy concerns in contrast to generic small molecule drugs. In Mexico, several filgrastim-intended copies (FIC) have been available and marketed since 2001, while no clinical comparability studies to evaluate their use in this setting have been published and thus are not considered to be true biosimilars. In this study, we report our experience using three different FIC products currently available (Filatil, Dextrifyl, and Biofilgran). METHODS: We retrospectively evaluated 118 related donors of all ages who received any brand 5 µg/kg subcutaneously twice daily for 4 days and were harvested in a single apheresis system on day 5. RESULTS: Donors had a median age of 38 years (range, 1-69). A successful harvest defined as ≥2 × 106 CD34+ cells/kg of recipient weight was achieved in 95.8% of cases, with a median CD34+ cell dose of 9.4 × 106 /kg (range 1-42.8). A single apheresis session was performed in 89.8% of cases. No significant difference in cell yield between each brand was observed. All pediatric donors had a successful harvest with similar results to adult donors. No immediate severe adverse effects were documented in any case. CONCLUSIONS: In conclusion, three FICs available in Mexico were efficacious and without immediate severe adverse effects, resulting in significant cost savings. Evaluation of immunogenicity and establishment of a pharmacovigilance program with the use of FICs is warranted.

Determination of Similarity Margin in Comparative Clinical Studies to Support the Development of Biosimilar Products of Neupogen® (Filgrastim, Granulocyte Colony-Stimulating Factor [G-CSF]).

To demonstrate a biological product is biosimilar to a reference product, the applicant needs to show that the product is highly similar and has no clinically meaningful differences. Comparative clinical studies are often conducted to support the conclusion of no clinically meaningful differences, as a part of totality of evidence. The FDA has published several guidance documents to facilitate the development of biosimilar products. While the guidance documents define the role and objective of comparative clinical studies, they do not provide details about the determination of the similarity margin. In this paper, we illustrate a similarity margin derivation for a surrogate endpoint in comparative clinical studies conducted to assess whether clinically meaningful differences exist between Neupogen® (Filgrastim, granulocyte colony-stimulating factor) and products proposed to be biosimilar to Neupogen®.

A multi-center pragmatic, randomized, feasibility trial comparing standard of care schedules of filgrastim administration for primary febrile neutropenia prophylaxis in early-stage breast cancer.

INTRODUCTION: The most effective duration of filgrastim as primary febrile neutropenia (FN) prophylaxis in early breast cancer (EBC) patients is unknown. Despite significant differences in cost and toxicity, no prospective trial has been performed to optimize practice. We assessed the feasibility of using a novel pragmatic trial model to compare the most commonly used schedules of filgrastim. METHODS: Early breast cancer patients receiving chemotherapy were randomized to 5, 7, or 10 days of filgrastim as primary FN prophylaxis. The trial methodology integrated broad eligibility criteria, simply defined endpoints, an integrated consent model incorporating oral consent, and web-based randomization in the clinic. Feasibility was reflected through a combination of primary endpoints including patient and physician engagement (if > 50% of appropriate patients approached agree to participate, and if > 50% of physicians approached patients for the study). Secondary endpoints included the first occurrence rates of FN, treatment-related hospital admission, or chemotherapy dose reductions/delays/discontinuation. RESULTS: From May 2015 to August 2016, 142/149 (95.3%) patients approached agreed to participate and were randomized. Seventeen of 24 (70.8%) medical oncologists approached and randomized patients. The 142 patients received a total of 495 cycles of chemotherapy. Aggregate incidences of a first event by patient were FN (8/142, 5.6%), treatment-related hospitalization (6/142, 4.2%), chemotherapy discontinuation (7/142, 4.9%), chemotherapy delays (5/142, 3.5%), and chemotherapy dose reduction (18/142, 12.7%). Overall, 31.7% (45/142) of patients and 9.0% (45/495) of chemotherapy cycles were associated with one of these first events. CONCLUSION: This study met its feasibility endpoints. This novel pragmatic trial approach offers a means of comparing standard of care treatments in a practical and cost-effective manner. The trial will now be expanded to compare rates of FN between the three filgrastim schedules. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02428114.

Comparison of biosimilar filgrastim, originator filgrastim, and lenograstim for autologous stem cell mobilization in patients with multiple myeloma.

BACKGROUND: Granulocyte-colony-stimulating factor (G-CSF) originators such as filgrastim (Neupogen) and lenograstim (Granocyte) are widely used for peripheral blood stem cell (PBSC) mobilization. In recent years, biosimilar agents have been approved for the same indications. The aim of this retrospective study was to compare the mobilization efficiency of the three G-CSF variants originator filgrastim, lenograstim, and the biosimilar Filgrastim Hexal in a homogeneous group of multiple myeloma (MM) patients in first-line therapy. STUDY DESIGN AND METHODS: Overall mobilization data of 250 patients with MM were included. Of these patients, 74 (30%), 131 (52%), and 45 (18%) were mobilized with originator filgrastim, biosimilar Filgrastim Hexal, or lenograstim, respectively, at a dose of 5 to 10 µg/kg body weight subcutaneously starting from Day 5 after chemomobilization with CAD (cyclophosphamide, doxorubicin, dexamethasone) until completion of PBSC collection. RESULTS: All but one patient reached the collection goal of a minimum of at least 2 × 106 CD34+ cells/kg body weight during a median of one (range, one to three) leukapheresis session. No significant differences in CD34+ mobilization and collection yields between the filgrastim-mobilized (median, 10.5; range, 2.7-40.4), Filgrastim Hexal-mobilized (median, 9.9; range, 0.2-26.0), and lenograstim-mobilized (median, 10.7; range, 3.1-27.9 CD34+ cells × 106 /kg body weight) patients were observed. CONCLUSION: Concerning the clinically relevant efficiencies of PBSC mobilization and in terms of reaching the individual collection target, this retrospective study did not detect any significant differences between the three G-CSF variants in the analyzed patient cohort.