Rapid diffuse alveolar hemorrhage associated with all-trans-retinoic acid and filgrastim

What is the role of biosimilar G-CSF agents in hematopoietic stem cell mobilization at present?

Mobilization of hematopoietic stem cells, which has largely replaced bone marrow harvesting as a source of hematopoietic stem cells, using recombinant agents such as filgrastim or lenograstim has become a standard procedure in both patients and healthy donors prior to peripheral blood stem cell collection for autologous and allogeneic stem cell transplantation. Published literature data suggest that mobilization with recombinant granulocyte-colony stimulating factor (G-CSF) is safe and mobilization outcomes are satisfactory. In recent years, besides G-CSF originators, biosimilar G-CSF agents have been approved by the regulatory agencies for the same indications. Current data showed that by using the biosimilar G-CSF, similar results regarding safety and efficacy of hematopoietic stem cell mobilization may be achieved compared to the originator G-CSF. Although the issues such as the similarity to a licenced biological medicine, differences in manufacturing processes, the potential to cause immunogenicity, extrapolation and interchangeability of these biosimilar products are still being discussed by the scientific area, however, more experience with these agents now exists in approved endications and there seems to be no reason to expect significant differences between biosimilar G-CSF and originator G-CSF regarding their efficacy and safety in both patients and healthy donors. Also, the significant cost savings of biosimilars in real life setting may enhance the use of these agents in the future. Nonetheless, the collection of long-term follow-up data is mandatory for both patients and healthy donors, and multicentre randomized clinical trials that directly compare biosimilar G-CSF with the originator G-CSF are needed in order to allow the transplant community to make informed decisions regarding the choice of G-CSF.

Biosimilar granulocyte-colony-stimulating factor for healthy donor stem cell mobilization: need we be afraid?

Biosimilars are approved biologics with comparable quality, safety, and efficacy to a reference product. Unlike generics, which are chemically manufactured copies of small-molecule drugs with relatively simple chemical structures, the biosimilar designation is applied to drugs that are produced by living organisms, implying much more difficult to control manufacturing and purification procedures. To account for these complexities, the European Medicines Agency (EMA), the US Food and Drug Administration, the Australian Therapeutic Goods Administration, and other regulatory authorities have devised and implemented specific, markedly more demanding pathways for the evaluation and approval of biosimilars. To date, several biosimilars have been approved, including versions of somatropin, erythropoietin, and granulocyte-colony-stimulating factor (G-CSF), and several biosimilar monoclonal antibodies are currently in development. The reference G-CSF product (Neupogen, Amgen) has been used for many years for prevention and treatment of neutropenia and also for mobilization of peripheral blood stem cells (PBSCs). However, concerns have been raised about the safety and efficacy of biosimilar G-CSF during PBSC mobilization procedures, especially in healthy donors. This article reviews the available evidence on the use of biosimilar G-CSF in this setting. Aggregate clinical evidence supports the assessment by the EMA of biosimilar and originator G-CSF as highly biologically similar, with respect to desired and undesired effects.