INTRODUCTION
Febrile neutropenia, breast cancer, reductions of cancer, cancer, toxicities, carcinoma
FEBRILE NEUTROPENIA, BREAST CANCER, CANCER, CARCINOMA, COMPLICATION, ONCOLOGY
Febrile neutropenia (FN) is the most common life‐threatening complication of myelosuppressive cancer chemotherapy. It is a major cause of morbidity, health care resource use and compromised treatment efficacy resulting from delays and dose reductions of cancer chemotherapy.Pegfilgrastim is a PEGylated form of filgrastim and is indicated to decrease the incidence of chemotherapy‐induced FN. While filgrastim is administered daily, pegfilgrastim prevents chemotherapy‐induced FN by once‐per‐chemotherapy‐cycle dosing. It is the first granulocyte colony‐stimulating factor (G‐CSF) approved for prophylactic use regardless of carcinoma type. The Japan Society of Clinical Oncology strongly recommends its use over daily filgrastim injection.Biological medicines are more expensive than small‐molecule medicines. Since the use of this therapy imposes a heavy financial burden on patients, less expensive biosimilars (BSs) have attracted attention as alternatives. Currently, there is no pegfilgrastim BS approved in Japan. MD‐110 was developed as the first BS to the originator, pegfilgrastim. Its active ingredient has an amino acid sequence bound to a methoxy polyethylene glycol (molecular weight: ca. 20,000) at N‐terminal methionine via linker, which is identical to that of the originator. Also, it has a high level of similarity to the originator in quality characteristics, pharmacological effects, and toxicities. Pharmacokinetic and pharmacodynamic bioequivalence between MD‐110 and the originator has been confirmed in healthy volunteers.This phase III, multicenter, open‐label, single‐arm study investigated the efficacy and safety of MD‐110 in patients with breast cancer receiving cancer chemotherapy.