A Phase II Study to Evaluate the Safety and Efficacy of Pegteograstim in Korean Breast Cancer Patients Receiving Dose-Dense Doxorubicin/Cyclophosphamide

Purpose Dose-dense chemotherapy (DD-CT) is a preferred (neo)adjuvant regimen in early breast cancer (BC). Although the results of reported randomized trials are conflicting, a recent metaanalysis showed improved overall and disease-free survival with DD-CT compared to conventional schedules. However, no DD-CT safety data for Korean BC patients are available. This phase II study was conducted to evaluate the safety and efficacy of pegteograstim in Korean BC patients receiving DD-CT. Materials and methods Patients with operable (stage I-III), histologically confirmed BC received four cycles of intravenous doxorubicin (60 mg/m2) and cyclophosphamide (600 mg/m2) on day 1 every 2 weeks as neoadjuvant or adjuvant therapy. Pegteograstim (6.0 mg) was administered subcutaneously on day 2 of each cycle. The primary endpoint was the incidence of febrile neutropenia (FN). The secondary endpoints were safety and tolerability. Results Of 63 patients, one (1.6%) developed FN during all cycles of DD-CT. Dose delay was observed in four patients (6.3%) and dose reduction in two (3.2%) during DD-CT. Frequent adverse events (AEs) were nausea, alopecia, generalized muscle weakness, myalgia, mucositis, anorexia, dyspepsia, and diarrhea; most AEs were related to chemotherapy. Grade 3-4 AEs were reported in five of 63 patients (7.9%), and all grade 3 and 4 AEs were related to chemotherapy. Adverse drug reactions possibly linked to pegteograstim were abdominal pain, bone pain, myalgia, generalized muscle weakness, and headache in five of 63 patients (7.9%). Conclusion Dose-dense AC (doxorubicin/cyclophosphamide) chemotherapywith pegteograstim support is a tolerable and safe regimen in Korean early BC patients.