Efficacy and safety of telpegfilgrastim in the prophylaxis of chemotherapy-induced neutropenia in breast cancer patients: A retrospective study.

e12515 Background: Chemotherapy-induced neutropenia (CIN) is a common complication during cancer chemotherapy, leading to febrile neutropenia (FN), reducing chemotherapy efficacy and increasing infection risk. Telpegfilgrastim, a new type of polyethylene glycol (PEG)-modified human granulocyte stimulating factor (rhG-CSF) with a unique 40KD Y-shaped branched PEG structure. Due to its structural characteristics, the dosage of the drug can be reduced, and it may offer advantages in terms of efficacy and safety. This study aims to evaluate the efficacy and safety of Telpegfilgrastim in preventing CIN in breast cancer patients. Methods: This study retrospectively analyzed 59 breast cancer patients from 01.April.2024 to 01.August.2024 who used Telpegfilgrastim the day after chemotherapy, for the prevention of chemotherapy-induced neutropenia (average age 49 years, 98.31% female, 66.10% coexisting with other tumors). The primary efficacy indicator was the incidence of grade 3/4 neutropenia during the chemotherapy cycle, while secondary efficacy indicators included the rate of antibiotic usage and the incidence of infections. Subgroup analysis compared the differences in the incidence of grade 3/4 neutropenia among different chemotherapy regimens. Results: Among a total of 91 chemotherapy cycles, the incidence of grade 3/4 neutropenia was 12.09% (11/91), and grade 4 neutropenia was 1.10% (1/91). In the first cycle, the incidence of grade 3/4 and grade 4 neutropenia was 13.56% (8/59) and 1.69% (1/59), respectively. The incidence of infection was 3.39% (2/59), and was not caused by low ANC. And the antibiotics usage rate was 5.08% (3/59), with 2 cases used for infection treatment and 1 case used for infectious prophylaxis. Subgroup analysis: Anthracycline-containing regimens showed a higher incidence of grade 3/4 neutropenia across all cycle compared to non-anthracycline-containing regimens (23.53% vs. 5.26%, P = 0.017). Common adverse events included reduced platelet count (27.27%), reduced white blood cell count (18.18%), and anemia (9.09%), and bone pain (3.39%), etc.. Most adverse events were grade 1 (42.42%) or grade 2 (39.39%). The safety is good and no serious adverse events related to the investigational drug have occurred. Conclusions: Telpegfilgrastim effectively prevented the occurrence of grade 3/4 neutropenia in breast cancer patients undergoing chemotherapy, reduced the incidence of infections and the use of antibiotics, with good safety. These data support Telpegfilgrastim as a feasible option for CIN prevention in clinical practice.